Magnetic field sensor system with magnetic eddy current for B-field redirection of out-of-plane magnetic field

Abstract

The invention relates to a magnetic field sensor system with magnetic eddy current for B-field redirection of an out-of-plane magnetic field. A magnetic sensor system includes: a magnetoresistive sensor including a magnetically free layer having a sensing plane and a magnetically free magnetization disposed within the sensing plane, where the magnetically free magnetization is variable in the presence of an in-plane magnetic field aligned with the sensing plane; and a ferromagnetic disk having a magnetic eddy current in a ground state, where the magnetic eddy current is configured to react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk. The stray field has an in-plane magnetic field component proportional to the out-of-plane magnetic field. The magnetically free layer is configured to receive an in-plane magnetic field component of the stray field. The magnetic free magnetization is configured to vary based on an in-plane magnetic field component of the stray field.

Description

Background Art

[0001] Magnetic field sensors based on the magnetoresistance effect are called magnetoresistive sensors and are commonly used in magnetic field sensing applications such as current sensing, position sensing, and angle sensing. Magnetoresistance is a property of a material where the value of the material's resistance changes when an external magnetic field is applied to the material. Due to the high signal level and high accuracy of magnetoresistive sensors, as well as the possibility of integrating magnetoresistive sensors into complementary metal oxide semiconductor (CMOS) and bipolar CMOS (BiCMOS) technologies, magnetoresistive sensors can be a preferred choice over Hall-based sensors. Some types of magnetoresistive sensors include anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, and tunnel magnetoresistive (TMR) sensors, each of which utilizes a corresponding magnetoresistive effect.

[0002] There are many applications that require measuring current. As an example, it may be desirable to measure one or more currents of a battery system of an electric vehicle. In another example, it may be desirable to measure one or more currents provided to a load such as a motor. In yet another example, it may be desirable to measure one or more currents of a power distribution system or one or more currents in a circuit.

[0003] Because the current flowing through the current-carrying conductor generates a magnetic field with a magnetic field flux density proportional to the amplitude of the current, a magnetic field sensor can be used as a current sensor. By placing the magnetic field sensor near the current-carrying conductor, the magnetic field sensor can generate a measurable quantity, such as a voltage, that is proportional to the magnetic field sensed by the magnetic field sensor. However, the magnetic field flux density in the space around the current-carrying conductor decreases as the distance from the current-carrying conductor increases. Therefore, the sensor element of the magnetic field sensor can be placed in close proximity to the current-carrying conductor.

[0004] In addition, the magnetic field sensor can be used to sense the position of an object. As an example, a magnet can be coupled to an object of interest (e.g., a target object). As a result, if the magnetic field sensor is placed in a fixed position, the magnetic field generated by the magnet and sensed at the magnetic field sensor changes as the position of the object changes. For example, the magnetic field flux density of the magnetic field incident on the magnetic field sensor can increase as the object moves closer to the magnetic field sensor together with the magnet, and can decrease as the object moves away from the magnetic field sensor together with the magnet. Therefore, by placing the magnetic field sensor near the track of the magnet, the magnetic field sensor can generate a measurable quantity (such as a voltage) that is proportional to the position of the object in the magnetic field generated by the magnet. Summary of the invention

[0005] In some embodiments, a magnetic sensor system includes: a magnetoresistive sensor including a magnetic free layer, the magnetic free layer having a sensing plane and a magnetic free magnetization arranged in the sensing plane, wherein the magnetic free magnetization is variable in the presence of an in-plane magnetic field aligned with the sensing plane; and a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to: react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has an in-plane magnetic field component proportional to the out-of-plane magnetic field, wherein the magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and wherein the magnetic free magnetization is configured to: change based on the in-plane magnetic field component of the stray field.

[0006] In some embodiments, a magnetic sensor system includes: a first magnetoresistive sensor having a first sensitive axis and a first magnetic free layer, the first magnetic free layer having a first magnetic free magnetization, the first magnetic free magnetization being variable in the presence of an in-plane magnetic field aligned with the first sensitive axis; a second magnetoresistive sensor having a second sensitive axis and a second magnetic free layer, the second magnetic free layer having a second magnetic free magnetization, the second magnetic free magnetization being variable in the presence of an in-plane magnetic field aligned with the second sensitive axis; and a ferromagnetic disk having a magnetic eddy current in a ground state, wherein the magnetic eddy current is configured to: react to an out-of-plane magnetic field, and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field decays as the distance from the ferromagnetic disk increases, wherein the first magnetoresistive sensor is arranged within the stray field, and the second magnetoresistive sensor is arranged outside the stray field, wherein the stray field has an in-plane magnetic field component proportional to the out-of-plane magnetic field, wherein the first magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and wherein the first magnetic free magnetization is configured to: change based on the in-plane magnetic field component of the stray field.

[0007] In some embodiments, a magnetic sensor system includes: a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to: react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has a first in-plane magnetic field component and a second in-plane magnetic field component proportional to the out-of-plane magnetic field, and wherein the first in-plane magnetic field component has a first vector in a first direction and the second in-plane magnetic field component has a second vector in a second direction, the second direction being antiparallel to the first direction; a first magnetoresistive sensor including a first sensitive axis and a first magnetically free layer, the first magnetically free layer having a first magnetic free magnetization, the first magnetic free magnetization being variable in the presence of an external in-plane magnetic field aligned with the first sensitive axis; and a second magnetoresistive sensor having a second sensitive axis and a second magnetic free layer, the second magnetic free layer having a second magnetic free magnetization, the second magnetic free magnetization being variable in the presence of an external in-plane magnetic field aligned with the second sensitive axis, wherein the first sensitive axis is parallel to the second sensitive axis, wherein the first magnetoresistive sensor is arranged within the first in-plane magnetic field component of the stray field to detect the first vector, and wherein the second magnetoresistive sensor is arranged within the second in-plane magnetic field component of the stray field to detect the second vector. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Embodiments are described herein with reference to the accompanying drawings.

[0009] Figure 1 is a diagram of an example magnetic field sensor according to one or more implementations.

[0010] Figure 2 An example of a layer stack of a magnetoresistive sensing element according to one or more embodiments is shown.

[0011] Figure 3 An example of a magnetic sensor system according to one or more implementations is shown.

[0012] Figure 4A An example of a graph showing the magnetization of a ferromagnetic disk according to one or more embodiments.

[0013] Figure 4B An example of a graph showing the decay response of an in-plane magnetic field component of a stray field in accordance with one or more embodiments is shown.

[0014] Figure 5 An example of a magnetic sensor system according to one or more implementations is shown.

[0015] Figure 6 An example of a magnetic sensor system according to one or more implementations is shown. DETAILED DESCRIPTION

[0016] In the following, details are set forth to provide a more thorough explanation of example embodiments. However, it will be apparent to those skilled in the art that these embodiments may be practiced without these specific details. In other cases, well-known structures and devices are shown in block diagram form or in schematic form rather than in detail to avoid obscuring the embodiments. In addition, unless otherwise specifically stated, the features of the different embodiments described below may be combined with each other.

[0017] In addition, in the following description, identical or similar reference numerals are used to represent identical or similar elements or elements having identical or similar functions. Since identical or functionally equivalent elements are assigned the same reference numerals in the drawings, repeated descriptions of elements provided with the same reference numerals may be omitted. Therefore, descriptions provided for elements having the same or similar reference numerals are interchangeable.

[0018] Each of the illustrated x-axis, y-axis, and z-axis is substantially perpendicular to the other two axes. In other words, the x-axis is substantially perpendicular to the y-axis and the z-axis, the y-axis is substantially perpendicular to the x-axis and the z-axis, and the z-axis is substantially perpendicular to the x-axis and the y-axis. In some cases, a single reference numeral is shown to refer to a surface, or less than all instances of a component may be labeled with all surfaces of the component. Although not every surface is labeled, all instances of a component may include an associated surface of the component.

[0019] The orientation of various elements in the accompanying drawings is shown as an example, and the examples shown can be rotated relative to the orientation depicted. The description provided herein and the subsequent claims relate to any structure having the described relationship between various features, whether the structure is in the specific orientation of the figure, or rotated relative to this orientation. Similarly, for ease of description, spatially related terms (such as "top", "bottom", "below", "below", "lower", "above", "upper", "middle", "left" and "right") are used herein to describe the relationship between an element and one or more other elements as illustrated in the accompanying drawings. In addition to the orientation depicted in the accompanying drawings, spatially related terms are intended to cover different orientations of elements, structures and / or components in use or operation. Structures and / or components can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used in this article can be interpreted accordingly. In addition, in order to simplify the accompanying drawings, unless otherwise indicated, the cross-sectional views in the accompanying drawings only show the features in the plane of the cross section, and the material behind the plane of the cross section is not shown.

[0020] It should be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.).

[0021] In the embodiments described herein or shown in the accompanying drawings, any direct electrical connection or coupling (e.g., any connection or coupling without additional intermediate elements) may also be achieved through an indirect connection or coupling (e.g., a connection or coupling with one or more additional intermediate elements, or vice versa), as long as the general purpose of the connection or coupling is basically maintained (e.g., transmitting a certain type of signal or transmitting a certain type of information). Features from different embodiments may be combined to form further embodiments. For example, unless otherwise indicated, changes or modifications described with respect to one embodiment in the embodiments may also apply to other embodiments.

[0022] As used herein, the terms "substantially" and "approximately" mean "within reasonable tolerances of manufacturing and measurement." For example, the terms "substantially" and "approximately" may be used herein to illustrate small manufacturing tolerances or other factors that are considered acceptable in the industry (e.g., within 5%) without departing from aspects of the embodiments described herein. For example, a resistor having an approximate resistance value may actually have a resistance within 5% of the approximate resistance value. As another example, a signal having an approximate signal value may actually have a signal value within 5% of the approximate signal value.

[0023] In the present disclosure, expressions including ordinal numbers (such as "first", "second", etc.) can modify various elements. However, such elements are not limited by such expressions. For example, such expressions do not limit the order and / or importance of elements. On the contrary, such expressions are used only for the purpose of distinguishing one element from other elements. For example, a first box and a second box indicate different boxes, although both are boxes. For another example, a first element may be referred to as a second element, and similarly, a second element may also be referred to as a first element, without departing from the scope of the present disclosure.

[0024] A "sensor" may refer to a component that converts a property to be measured into an electrical signal (e.g., a current signal or a voltage signal). The property to be measured may include, for example, a magnetic field, an electric field, an electromagnetic wave (e.g., a radio wave), a pressure, a force, a current, or a voltage, but is not limited thereto. For example, there are various sensor technologies for measuring a current flowing through a conductor or the position of an object relative to a magnetic field. For example, a system may include a current-carrying conductor that carries a current to be measured. A magnetic field sensor may detect the magnetic field generated by the current and generate a sensor signal that is proportional to the magnetic field. Thus, the sensor signal may be a measure of the current.

[0025] As another example, the system may include a magnet coupled to a movable target object. When the movable target object moves along a predetermined path, the magnet may move relative to the magnetic field sensor. When the magnet moves closer to the magnetic field sensor, the magnetic field generated by the magnet may become more dense (e.g., more concentrated or stronger) in the area of ​​the magnetic field sensor. On the contrary, when the magnet moves away from the magnetic field sensor, the magnetic field may become less dense (e.g., less concentrated or weaker) in the area of ​​the magnetic field sensor. The magnetic field sensor may detect the magnetic field generated by the magnet and generate a sensor signal proportional to the magnetic field. Therefore, the sensor signal may be a measure of the position of the magnet relative to the magnetic field sensor.

[0026] As another example, a magnet can be coupled to a magnetic field sensor as a back-bias magnet. The movable target object can be configured to affect the magnetic field of the back-bias magnet when the movable target object moves along a predetermined path. For example, the movable target object can be made of a ferromagnetic material. As a result, when the movable target object moves closer to the back-bias magnet, the magnetic field can become denser (e.g., more concentrated or stronger) in the area of ​​the magnetic field sensor, and when the movable target object moves away from the back-bias magnet, the magnetic field can become less dense (e.g., less concentrated or weaker) in the area of ​​the magnetic field sensor. The magnetic field sensor can detect the magnetic field generated by the back-bias magnet and generate a sensor signal proportional to the magnetic field. Therefore, the sensor signal can be a measure of the position of the movable target object relative to the magnetic field sensor.

[0027] Due to shape anisotropy, the magnetization of a magnetoresistive-based sensor is usually located in a plane. Therefore, a magnetoresistive-based sensor can only detect in-plane magnetic fields (i.e., in-plane B-fields) and cannot detect out-of-plane magnetic fields (i.e., out-of-plane B-fields). The in-plane magnetic field is the magnetic field that is aligned parallel to the chip plane of the magnetoresistive-based sensor (e.g., the chip surface), while the out-of-plane magnetic field is the magnetic field that extends outside the chip plane of the magnetoresistive-based sensor (e.g., the chip surface). However, in some applications, it may be necessary to use a magnetoresistive-based sensor to detect and / or measure out-of-plane magnetic fields.

[0028] Therefore, some embodiments disclosed herein are directed to a magnetic field sensor system including a ferromagnetic disk, which is configured to redirect an out-of-plane magnetic field into a sensing plane of a magnetoresistive-based sensor via a stray field, so that the magnetoresistive-based sensor can measure the out-of-plane magnetic field. For example, the ferromagnetic disk may have a magnetic eddy current in a ground state. In other words, the ferromagnetic disk may have a closed flux magnetization in an eddy current state. The magnetic eddy current of the ferromagnetic disk may be configured to react linearly to the out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk. The stray field may have an in-plane magnetic field component proportional to the out-of-plane magnetic field, and the magnetic free layer of the magnetoresistive-based sensor may be configured to receive the in-plane magnetic field component of the stray field so that the magnetic free magnetization of the magnetic free layer changes based on the in-plane magnetic field component of the stray field. Therefore, by converting the out-of-plane magnetic field into a stray field having an in-plane magnetic field component that can be sensed by the magnetoresistive-based sensor, the ferromagnetic disk enables the magnetoresistive-based sensor to measure the out-of-plane magnetic field.

[0029] Magnetic eddy currents are generated in the ferromagnetic disk based on the volume of the ferromagnetic disk. The thickness of the ferromagnetic disk can be less than 600nm, while being able to generate and maintain magnetic eddy currents in the ferromagnetic disk. In addition, the linear stray field response of the magnetic eddy current is defined by the aspect ratio of the ferromagnetic disk. The aspect ratio is the ratio between the thickness of the ferromagnetic disk and the diameter of the ferromagnetic disk. Therefore, the magnetic eddy current provides a linear response to the out-of-plane magnetic field so that the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field. The ability of the magnetic eddy current of the ferromagnetic disk to redirect the out-of-plane magnetic field into an in-plane magnetic field component for local B-field redirection in a linear manner enables the ferromagnetic disk to be thinner (e.g., formed with a thickness of less than 600nm), which has advantages over more expensive redirection methods in terms of material cost and manufacturing cost. For example, the ferromagnetic disk can be made of a soft ferromagnetic material (e.g., iron or an iron alloy, such as nickel iron (NiFe)), and the thickness of the ferromagnetic disk can be less than 600nm, or less than 500nm, or less than 400nm, or less than 300nm, or less than 200nm, or less than 100nm. Furthermore, the ferromagnetic disk only needs to be positioned within the out-of-plane magnetic field and close enough to the magnetoresistive-based sensor so that the magnetoresistive-based sensor receives a portion of the stray field that responds linearly to the out-of-plane magnetic field. Therefore, the ferromagnetic disk can be more easily integrated into a magnetic field sensor system than other more complex redirection methods. This simple integration can result in reduced manufacturing costs.

[0030] In addition, the uniform magnetic field present at the magnetic field sensor may interfere with the magnetic field to be measured. For example, the uniform magnetic field can be generated by a nearby current rail or another magnetic field source that is common in electric vehicles. The uniform magnetic field incident on the magnetic field sensor may cause the magnetic field sensor to output a sensor signal that is not an accurate measurement of the magnetic field to be measured. Therefore, sensitivity to the uniform magnetic field may cause the magnetic field sensor to output unreliable sensor information, which may cause the system that relies on the sensor information to operate incorrectly. In addition, when the magnetic field sensor is used in safety-related applications, sensitivity to the uniform magnetic field may cause an unsafe environment for the user or the object used in conjunction with the magnetic field sensor. Therefore, in some embodiments, the magnetic sensor system can be configured to cancel the uniform magnetic field.

[0031] Figure 1 is a diagram of an example magnetic field sensor 100 according to one or more implementations. Figure 1 As shown in , magnetic field sensor 100 may include one or more sensing elements 110 (eg, one or more magnetic field sensing elements), an analog-to-digital converter (ADC) 120 , a digital signal processor (DSP) 130 , a memory element 140 , and an interface 150 .

[0032] The magnetic field sensor 100 may be a semiconductor chip (e.g., a sensor chip) that includes one or more sensing elements 110 that measure or otherwise sense one or more characteristics of a magnetic field (e.g., the amount of magnetic field flux density, field strength, field angle, field direction, field orientation, etc.), and provide a sensor signal corresponding to the sensed magnetic field characteristics. For example, the sensing element 110 may be configured to generate a sensor signal (e.g., a voltage or a measurable resistance) in response to one or more magnetic fields impinging on the sensing element 110. Thus, the sensor signal indicates the amplitude and / or field orientation of at least one magnetic field impinging on the sensing element 110. The semiconductor chip may also include a sensor circuit for processing and outputting one or more sensor signals generated by the one or more sensing elements 110. In some embodiments, the sensing element 110 may be distributed over two or more semiconductor chips.

[0033] The magnetic field may be generated by a magnet, a current-carrying conductor (e.g., a wire, a lead frame, or a busbar), the earth, or another magnetic field source. The sensing element 110 has a "sensitive axis" or "sensing axis". The sensing element is sensitive to the magnetic field component that is projected onto the sensitive axis or aligned with the sensitive axis. In addition, the sensing element 110 is substantially insensitive to the magnetic field component that is not projected onto the sensitive axis or aligned with the sensitive axis. The magnetic field component may be, for example, an x ​​magnetic field component Bx, a y magnetic field component By, or a z magnetic field component Bz. In the example described herein, the x magnetic field component Bx and the y magnetic field component By are aligned in-plane with the semiconductor chip, and the z magnetic field component Bz is aligned out-plane with the semiconductor chip. Therefore, the x magnetic field component Bx and the y magnetic field component By may be referred to as "in-plane" magnetic field components that are aligned parallel to the chip plane (e.g., chip surface) of the semiconductor chip. In contrast, the z magnetic field component Bz may be referred to as an "out-of-plane" magnetic field component that extends outside the chip plane (e.g., chip surface) of the semiconductor chip. For example, the z magnetic field component Bz extends perpendicular to the chip plane.

[0034] In some embodiments, the magnetic field sensor 100 includes a plurality of sensing elements 110 that are sensitive in two or more different directions. For example, the magnetic field sensor 100 may include a first sensing element configured to sense a first magnetic field component (e.g., an x ​​magnetic field component Bx), a second sensing element configured to sense a second magnetic field component (e.g., a y magnetic field component By), and a third Hall-based sensing element configured to sense a third magnetic field component (e.g., a z magnetic field component Bz). That is, in some embodiments, the magnetic field sensor 100 may be a 2D magnetic field sensor or a 3D magnetic field sensor configured to sense magnetic fields in multiple dimensions.

[0035] The sensing element 110 may include one or more magnetoresistance-based sensing elements (i.e., magnetoresistance sensing elements). Magnetoresistance is a property of a magnetoresistance material (e.g., NiFe) whose value of resistance or conductance changes when a magnetic field is applied to the magnetoresistance material. Thus, the resistance of a magnetoresistance material may depend on the strength and / or direction of the magnetic field present at the magnetoresistance material. Some examples of various magnetoresistance effects include: giant magnetoresistance (GMR), which is a quantum mechanical magnetoresistance effect observed in thin film structures consisting of alternating ferromagnetic and non-magnetic conductive layers; tunnel magnetoresistance (TMR), which is a magnetoresistance effect occurring in a magnetic tunnel junction (MTJ), which is a component comprising two ferromagnets separated by a thin insulator; or anisotropic magnetoresistance (AMR), which is a property of a material in which a dependence of resistance on the angle between the current direction and the magnetization direction is observed. For example, in the case of an AMR sensor, the resistance of an AMR sensing element changes according to the square of the sine of the angle of the magnetic field component projected on the sensitive axis of the AMR sensing element.

[0036] Various magnetoresistive effects are often abbreviated as xMR, where "x" serves as a placeholder for various magnetoresistive effects. An xMR sensor can detect the field orientation of an applied magnetic field by measuring the sine and cosine angular components with a monolithically integrated magnetoresistive sensing element.

[0037] The magnetoresistive sensing element of such an xMR sensor typically includes a plurality of layers, at least one of the plurality of layers being a reference layer having a reference magnetization (e.g., a reference direction). The reference magnetization provides a sensing direction, which defines a sensitive axis of the magnetoresistive sensing element. This typically means that the sensitive axis of the magnetoresistive sensing element is parallel to the chip plane, which is defined by the main surface of the semiconductor chip in which the magnetoresistive sensing element is integrated. Therefore, the magnetoresistive sensing element is sensitive to magnetic field components extending parallel to the main surface of the semiconductor chip or extending coplanar with the main surface of the semiconductor chip. Therefore, if the magnetic field component points exactly in the same direction as the reference direction, the resistance of the magnetoresistive sensing element is at a minimum, and if the magnetic field component points exactly in the opposite direction to the reference direction, the resistance of the magnetoresistive sensing element is at a maximum.

[0038] Therefore, the resistance or the voltage drop across the magnetoresistive sensing element caused by the resistance is proportional to the magnetic field and can be used as the sensor signal of the magnetoresistive sensing element.In addition, in some embodiments, the xMR sensor includes multiple magnetoresistive sensing elements, which can have the same or different reference magnetizations.

[0039] Thus, the magnetoresistive sensing element can be used to measure a magnetic field parallel to the chip plane of the magnetic field sensor 100. Two or more sensing elements and corresponding sensor circuits can be housed (e.g., integrated) in the same semiconductor chip. The sensor circuit can be referred to as a signal processing circuit and / or a signal conditioning circuit that receives one or more signals (e.g., sensor signals) from one or more sensing elements in the form of raw measurement data, and derives a measurement signal representing a magnetic field from the one or more signals. For example, the sensor circuit can be configured to condition and amplify the sensor signal of one or more sensing elements 110 via signal processing and / or conditioning.

[0040] In some embodiments, the sensor circuit can be configured to combine two or more sensor signals (e.g., by addition, subtraction, or superposition) to generate a combined sensor signal. For example, a differential sensor signal is a type of combined sensor signal that represents the difference between two sensor signals. In some cases, the sensor circuit can generate a differential sensor signal based on sensor signals generated by two or more sensing elements 110 having the same sensitive axis (e.g., two sensing elements 110 sensitive to the same magnetic field component) using a differential circuit configured to differentially combine signals. Sensing elements electrically connected in a half-bridge configuration or a full-bridge configuration (e.g., a Wheatstone bridge) are examples of differential circuits that can be used to generate differential sensor signals. Additionally or alternatively, the differential circuit can include a differential amplifier, an adder, a subtractor, a combiner, a logic circuit, and / or a processor (e.g., a processor that applies differential operations) to differentially combine signals to generate a differential sensor signal. Therefore, the differential sensor signal can be a measurement signal that provides robustness to uniform external stray magnetic fields.

[0041] The above examples of sensing element 110 are provided for illustration purposes, and in reality, sensing element 110 may include any type of magnetoresistive sensing element capable of sensing a characteristic of a magnetic field and enabling a sensor signal to be provided to a sensor circuit.

[0042] ADC 120 may include an analog-to-digital converter that converts analog signals from one or more sensing elements 110 into digital signals. For example, ADC 120 may convert analog signals received from the group of sensing elements 110 into digital signals (e.g., digital samples) to be processed by DSP 130. ADC 120 may provide the digital signals to DSP 130. In some embodiments, magnetic field sensor 100 may include one or more ADCs 120. For example, different ADCs 120 may be configured to receive analog signals from different groups of sensing elements 110.

[0043] DSP 130 may include a digital signal processing device or a collection of digital signal processing devices. In some embodiments, DSP 130 may receive a digital signal from ADC 120 and may process the digital signal to form an output signal (e.g., to a controller), such as an output signal conveying sensor data, as described elsewhere herein. In some embodiments, the output signal may be referred to as a measurement signal.

[0044] The memory element 140 may include a read-only memory (ROM) (e.g., EEPROM), a random access memory (RAM), and / or another type of dynamic or static storage device (e.g., flash memory, magnetic memory, optical memory, etc.) that stores information and / or instructions used by the magnetic field sensor 100. In some embodiments, the memory element 140 may store information associated with the processing performed by the DSP 130. Additionally or alternatively, the memory element 140 may store configuration values ​​or parameters for one or more sensing elements 110, and / or information for one or more other components of the magnetic field sensor 100 (such as the ADC 120 or the interface 150).

[0045] The interface 150 may include an interface via which the magnetic field sensor 100 may receive information from and / or provide information to another device in the system, such as a controller. For example, the interface 150 may provide an output signal determined or otherwise generated by the DSP 130 to the controller, and may also receive information from the controller. In some embodiments, the interface 150 may be a communication interface that receives an output signal from the DSP 130 and provides the output signal as a communication signal according to a communication protocol, which may include transmitting the output signal as a communication signal or generating a communication signal based on the output signal.

[0046] As mentioned above, Figure 1 Other examples can be found in reference Figure 1 Different than described. Figure 1 The number and arrangement of components shown in FIG. 1 are provided as examples. In practice, the magnetic field sensor 100 may include Figure 1 Additional components, fewer components, different components, or differently arranged components than those shown in FIG. Figure 1 Two or more components shown in may be implemented in a single component, or Figure 1 The single components shown in may be implemented as multiple distributed components. Additionally or alternatively, one set of components (eg, one or more parts) of magnetic field sensor 100 may perform one or more functions described as being performed by another set of components of magnetic field sensor 100.

[0047] Figure 2An example of a layer stack of a magnetoresistive sensing element 200 according to one or more embodiments is shown. For example, the magnetoresistive sensing element 200 may be a TMR sensing element having a bottom-pinned spin valve (BSV) configuration. In addition, the magnetoresistive sensing element 200 may be arranged on a semiconductor substrate (not shown) of a magnetoresistive sensor. If described in a Cartesian coordinate system having two-to-two perpendicular coordinate axes x, y, and z, the layers of the layer stack extend laterally in a plane spanned by the x-axis and the y-axis. Therefore, a lateral dimension (e.g., a lateral distance, a lateral cross-sectional area, a lateral area, a lateral extension, a lateral displacement, etc.) may refer to a dimension in the xy plane, and a vertical dimension may refer to a dimension in the z direction perpendicular to the xy plane. For example, the vertical extent of a layer in the z direction may be described as a layer thickness.

[0048] The layer stack of the magnetoresistive sensing element 200 includes at least one reference layer having a reference magnetization (e.g., a reference direction in the case of GMR or TMR technology). The reference magnetization is a magnetization direction that provides a sensing direction corresponding to the sensing axis of the magnetoresistive sensing element 200. The reference layer and therefore the reference magnetization define a sensor plane. For example, the sensor plane can be defined by an xy plane. Therefore, the x-direction and the y-direction can be referred to as "in-plane" relative to the sensor plane, and the z-direction can be referred to as "out-of-plane" relative to the sensor plane.

[0049] Therefore, in the case of a GMR sensing element or a TMR sensing element, if the magnetic free magnetization of the magnetic free layer happens to point in the same direction as the reference magnetization (e.g., the reference direction), the resistance of the magnetoresistive sensing element 200 is at a minimum, and if the magnetic free magnetization of the magnetic free layer happens to point in the opposite direction to the reference magnetization, the resistance of the magnetoresistive sensing element 200 is at a maximum. The orientation of the magnetic free magnetization of the magnetic free layer is variable in the presence of an external magnetic field. In a magnetoresistive sensing element with a magnetic vortex free layer, the magnetic free magnetization of the magnetic free layer is in the form of a magnetic vortex, which is a circular magnetization pattern with a core at the center. When an external magnetic field is applied to the magnetic free layer, the external magnetic field can displace the core of the magnetic vortex and change the resistance or conductance of the magnetoresistive sensing element. Therefore, the resistance or conductance of the magnetoresistive sensing element 200 can change based on the influence of the external magnetic field on the magnetic free magnetization of the magnetic free layer.

[0050] From bottom to top, the magnetoresistive sensing element 200 may include an optional seed layer 202, which may be used to influence and / or optimize stack growth. In some embodiments, the seed layer 202 may be copper, tantalum, ruthenium, or a combination thereof. A natural antiferromagnetic (NAF) layer 204 is formed or otherwise disposed on the seed layer 202. The NAF layer 204 may be made of platinum-manganese (PtMn), iridium-manganese (IrMn), nickel-manganese (NiMn), etc. The film thickness of the NAF may be in the range of 5nm to 50nm.

[0051] In addition, a pinned layer (PL) 206 may be formed or otherwise arranged on the NAF layer 204. The pinned layer 206 may be made of a ferromagnetic material, such as cobalt iron (CoFe) or cobalt iron boron (CoFeB). The contact between the NAF layer 204 and the pinned layer 206 may induce an effect known as an exchange bias effect, which aligns the magnetization of the pinned layer 206 in a preferred direction (e.g., in the x-direction, as shown). The magnetization of the pinned layer 206 may be referred to as pinned magnetization. The pinned layer 206 may include a closed flux magnetization pattern in the xy plane. This closed flux magnetization pattern of the pinned layer 206 may be generated during the manufacture of the magnetoresistive sensing element 200 and may be permanently fixed. Alternatively, the pinned layer 206 may include a permanently fixed linear magnetization pattern in the xy plane (e.g., uniformly oriented in one direction).

[0052] The magnetoresistive sensing element 200 also includes a nonmagnetic layer (NML) referred to as a coupling interlayer 208. The coupling interlayer 208 may be diamagnetic and may include, for example, ruthenium, iridium, copper, a copper alloy, or the like. A magnetic (e.g., ferromagnetic) reference layer (RL) 210 may be formed or otherwise disposed on the coupling interlayer 208. The pinned layer 206 and the magnetic reference layer 210 may each have a thickness in the range of 1 nm to 10 nm.

[0053] Thus, the coupling interlayer 208 may be disposed between the pinned layer 206 and the magnetic reference layer 210 to spatially separate the pinned layer 206 and the magnetic reference layer 210 in a vertical direction. In addition, the coupling interlayer 208 may provide an interlayer exchange coupling (e.g., an antiferromagnetic Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling) between the pinned layer 206 and the magnetic reference layer 210 to form an artificial antiferromagnet. As a result, the magnetization of the magnetic reference layer 210 may be aligned and maintained in a direction antiparallel or opposite to the magnetization of the pinned layer 206 (e.g., in the -x direction, as shown). The magnetization of the magnetic reference layer 210 may be referred to as a reference magnetization.

[0054] Since the NAF layer 204 is configured to align and fix the magnetization of the pinned layer 206 in a certain direction, and the coupling interlayer 208 is configured to align and fix the magnetization of the magnetic reference layer 210 in the opposite direction, it can be said that the NAF layer 204 is configured to: maintain the magnetization of the pinned layer 206 (e.g., fixed pinned magnetization) in a first magnetic orientation, and maintain the magnetization of the magnetic reference layer 210 (e.g., fixed reference magnetization) in a second magnetic orientation. For example, if the pinned layer 206 includes a linear magnetization pattern in a certain direction in the xy plane, the magnetic reference layer 210 may include a linear magnetization pattern in an antiparallel direction. Therefore, the NAF layer 204, the pinned layer 206, the coupling interlayer 208, and the magnetic reference layer 210 form a magnetic reference layer system 212 of the magnetoresistive sensing element 200.

[0055] The magnetoresistive sensing element 200 additionally includes a barrier layer 214 (e.g., a tunnel barrier layer) vertically disposed between the reference layer system 212 and the magnetic free layer 216. For example, the barrier layer 214 can be formed or otherwise disposed on the magnetic reference layer 210 of the reference layer system 212, and the magnetic free layer 216 can be formed or otherwise disposed on the barrier layer 214.

[0056] The barrier layer 214 may be made of a non-magnetic material. In some embodiments, the barrier layer 214 may be an electrically insulating tunnel barrier layer. For example, the barrier layer 214 may be a tunnel barrier layer for generating a TMR effect. The barrier layer 214 may include magnesium oxide (MgO) or another material having similar properties.

[0057] The material of the magnetic free layer 216 can be an alloy of ferromagnetic materials, such as CoFe, CoFeB or NiFe. The magnetic free layer 216 has a magnetic free magnetization that is variable in the presence of an external in-plane magnetic field. Therefore, the magnetic free layer 216 can be called a sensor layer because the change in the magnetic free magnetization is used to determine the measured variable (e.g., the resistance or conductance of the magnetoresistive sensing element 200). In addition, the magnetic free magnetization has a default magnetic orientation in the ground state. The ground state is a state in which the influence of the external in-plane magnetic field on the magnetic free layer 216 does not exist or is negligible. In some embodiments, the magnetoresistive sensing element 200 may include a magnetic free system, which includes multiple layers (e.g., two or more magnetic free layers), which are combined to act as a magnetic free layer. In this case, the magnetic free layers of the magnetic free system are magnetically coupled to each other. Therefore, the magnetic free system can act as a magnetic free layer, but can include multiple layers. The magnetic free system has a magnetic free magnetization, wherein the magnetic free magnetization is variable in the presence of an external in-plane magnetic field.

[0058] The magnetic free magnetization of the magnetic free layer 216 can be a magnetic eddy current free layer with a closed flux magnetization in an eddy current state. In other words, the magnetization pattern of the magnetic free magnetization can form a closed loop. As a result, the magnetoresistive sensing element 200 has a conductance or resistance, and the magnetoresistive sensing element 200 can be configured to: based on the linear change of the magnetic free magnetization of the magnetic free layer 216 in response to (e.g., proportional to) the external in-plane magnetic field, and present a linear change in conductance or resistance proportional to the external in-plane magnetic field. Therefore, the magnetoresistive sensing element 200 can be a linear magnetoresistive sensor having a linear sensor response to the external in-plane magnetic field.

[0059] The cap layer 218 is made of, for example, tantalum (Ta), tantalum nitride (TaN), ruthenium (Ru), titanium (Ti), titanium nitride (TiN), platinum (Pt), etc., and can be formed or otherwise arranged on the magnetic free layer 216 to form an upper layer of the magnetoresistive sensing element 200.

[0060] The seed layer 202 may serve as a bottom electrode or may provide electrical contact with a bottom electrode (not shown) of the magnetoresistive sensing element 200. The cap layer 218 may provide electrical contact with a top electrode (not shown) of the magnetoresistive sensing element 200. The barrier layer 214 may be designed to allow electrons to tunnel between the reference layer system 212 and the magnetically free layer 216 when a bias voltage is applied to an electrode (not shown) of the magnetoresistive sensing element 200 to provide a magnetoresistive effect (e.g., a TMR effect).

[0061] As mentioned above, Figure 2 It is provided as an example only. Other examples can be found in Figure 2 Different than described. Figure 2 The number and arrangement of components shown in FIG. 2 are provided as examples. In practice, the magnetoresistive sensing element 200 may include Figure 2 Additional elements, fewer elements, different elements, or differently arranged elements than those shown in FIG.

[0062] Figure 3 300 according to one or more embodiments. The magnetic sensor system 300 may include a magnetoresistive sensor 302 and a ferromagnetic disk 304, the ferromagnetic disk 304 being spatially separated from the magnetoresistive sensor 302. The magnetoresistive sensor 302 may be a magnetic sensor 302 coupled to a magnetic field. Figure 2The magnetoresistive sensing element 302 is similar to the magnetoresistive sensing element 200 described above. Therefore, the magnetoresistive sensor 302 can be a linear magnetoresistive sensor having a magnetic vortex free layer as a magnetic free layer 306. The magnetic free layer 306 is used as a sensing layer for sensing an in-plane magnetic field. For example, the magnetic free layer 306 can have a sensing plane (e.g., an xy plane) and a magnetic free magnetization arranged in the sensing plane. In addition, the magnetic free magnetization is variable in the presence of an in-plane magnetic field aligned with the sensing plane (e.g., aligned with the sensitive axis of the magnetic reference layer (not clearly shown)).

[0063] The ferromagnetic disk 304 may be made of a soft magnetic material and may have a magnetic eddy current in a ground state. Therefore, the ferromagnetic disk 304 may have a closed flux magnetization in an eddy current state. The ferromagnetic disk 304 is configured to react to an out-of-plane magnetic field (such as a magnetic field out of plane relative to the sensing plane) and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk 304. In some embodiments, the out-of-plane magnetic field may be a Bz field aligned in the z direction orthogonal to the sensing plane. The stray field generated by the magnetic eddy current of the ferromagnetic disk 304 may include an in-plane magnetic field component proportional to the out-of-plane magnetic field. In other words, the ferromagnetic disk 304 may be configured to convert the out-of-plane magnetic field into a stray field having an in-plane magnetic field component. As a result, the ferromagnetic disk 304 may be configured to redirect the out-of-plane magnetic field as a stray field into the sensing plane of the magnetic free layer 306 so that the in-plane magnetic field component of the stray field is aligned in-plane with the sensing plane of the magnetic free layer 306.

[0064] In addition, the magnetic eddy current provides a linear response to the out-of-plane magnetic field (e.g., a linear stray field response) so that the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field. Therefore, based on the linear response function, the ferromagnetic disk 304 generates the in-plane magnetic field component of the stray field from the out-of-plane magnetic field, and based on the linear response function, the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field.

[0065] The magnetic free layer 306 is configured to receive the in-plane magnetic field component of the stray field, and the magnetic free magnetization of the magnetic free layer 306 is configured to change based on the in-plane magnetic field component of the stray field. That is, the magnetic free layer 306 is positioned at a position where the in-plane magnetic field component of the stray field is expected to exist. Since the change in magnetic free magnetization is proportional to the in-plane magnetic field component, and the in-plane magnetic field component is proportional to the out-of-plane magnetic field, the change in magnetic free magnetization is also proportional to the out-of-plane magnetic field. Therefore, the change in magnetic free magnetization can represent the amount of magnetic field flux density or the field strength of the out-of-plane magnetic field.

[0066] The aspect ratio between the thickness and the diameter of the ferromagnetic disk 304 defines the linear range portion of the stray field. The linear range portion of the stray field responds to the out-of-plane magnetic field in a linear manner based on the linear response function. The magnetic free magnetization of the magnetic free layer 306 responds to the linear range portion of the stray field in a linear manner. Therefore, the magnetic free layer 306 should be positioned at a position where the in-plane magnetic field component of the stray field has a linear response to the out-of-plane magnetic field.

[0067] The magnetic eddy currents of the ferromagnetic disk 304 are generated within the ferromagnetic disk 304 based on the volume of the ferromagnetic disk 304, and can be generated using a relatively thin soft ferromagnetic layer. For example, the thickness of the ferromagnetic disk can be less than 600nm, or less than 500nm, or less than 400nm, or less than 300nm, or less than 200nm, or less than 100nm. In addition, the linear stray field response of the magnetic eddy currents is defined by the aspect ratio of the ferromagnetic disk 304. The ability of the magnetic eddy currents of the ferromagnetic disk 304 to redirect the out-of-plane magnetic field into an in-plane magnetic field component for local B-field redirection in a linear and hysteresis-free manner enables the ferromagnetic disk to remain thin. In addition, when no external magnetic field is applied to the ferromagnetic disk 304, the ferromagnetic disk 304 does not generate a measurable stray field at the magnetic free layer 306. Depending on the volume of the ferromagnetic disk 304, the stray field can decay rapidly as the distance from the ferromagnetic disk 304 increases.

[0068] The magnetoresistive sensor 302 has a conductance or resistance that changes based on a change in the magnetic free magnetization of the magnetic free layer 306. Therefore, the magnetoresistive sensor 302 is configured to exhibit a linear change in conductance or resistance proportional to the out-of-plane magnetic field in response to a change in the in-plane magnetic field component of the stray field based on the magnetic free magnetization of the magnetic free layer 306. The sensor circuit can be used to read out or measure the conductance or resistance of the magnetoresistive sensor 302.

[0069] Figure 3 The number and arrangement of components shown in FIG. 3 are provided as examples. In practice, the magnetic sensor system 300 may include Figure 3 Additional components, fewer components, different components, or differently arranged components than those shown in FIG.

[0070] Figure 4A An example of a graph 400A showing the magnetization of a ferromagnetic disk according to one or more embodiments is shown. Graph 400A plots the magnetization of the ferromagnetic disk 304 according to an external out-of-plane magnetic field (μ0H 00P )'s relative out-of-plane (oop) magnetization (m oop ). In this example, the ferromagnetic disk has a diameter of 500 nm, which remains constant for different thicknesses of the ferromagnetic disk. The aspect ratio (thickness / diameter) defines the shape anisotropy and therefore the slope of the magnetization curve. The generated stray field is proportional to the magnetization.

[0071] The linear region of the stray field response of the ferromagnetic disk depends on the aspect ratio of the ferromagnetic disk. Therefore, the linear stray field response of the ferromagnetic disk can be controlled using the aspect ratio. Since the diameter remains constant in this example, the linear region of the stray field response depends on the thickness of the ferromagnetic disk. Figure 400A shows that a smaller thickness of the ferromagnetic disk results in a larger linear region of the stray field response. Therefore, the thickness of the ferromagnetic disk can be less than 500nm while providing a linear stray field response for measuring out-of-plane magnetic fields. In addition, the sensitivity of the ferromagnetic disk to out-of-plane magnetic fields can be increased at the expense of the linear range.

[0072] As mentioned above, Figure 4A Other examples can be found in reference Figure 4A Described differently.

[0073] Figure 4B An example of a graph 400B showing the decay response of the in-plane magnetic field component of the stray field according to one or more embodiments is shown. Graph 400B plots the change in magnetic flux density (mT) of the in-plane magnetic field component of the stray field with respect to the distance (μm) along the sensitive axis direction of the magnetoresistive sensor. Graph 400B shows three plots for three different z distances between the magnetoresistive sensor and the ferromagnetic disk (e.g., the ferromagnetic disk 304).

[0074] The stray field generated by the ferromagnetic disk according to the out-of-plane magnetic field decays (in some cases, decays rapidly) as the distance from the ferromagnetic disk in the direction of the sensitive axis increases. Therefore, the magnetoresistive sensor should be placed in a position where the stray field of the ferromagnetic disk 304 can be detected. For example, a ferromagnetic disk of 500nm (diameter)×300nm (thickness) may saturate at an out-of-plane field of 500mT. At a distance of about 500nm, the in-plane component of the stray field may be about 50mT. Therefore, in this example, about 10% of the external out-of-plane magnetic field can be redirected.

[0075] As mentioned above, Figure 4B Other examples can be found in reference Figure 4B Different than described.

[0076] Figure 5 1 shows an example of a magnetic sensor system 500 according to one or more embodiments. When the external magnetic field has an out-of-plane magnetic field component and at least one in-plane magnetic field component, the magnetic sensor system 500 can be used to measure the out-of-plane magnetic field (e.g., the out-of-plane magnetic field component of the external magnetic field). The magnetic sensor system 500 can include a magnetoresistive sensor 302 and a ferromagnetic disk 304, such as in combination with Figure 3The magnetic sensor system 300 is described as described above. In addition, the magnetic sensor system 500 may include an additional magnetoresistive sensor 502, which includes a magnetically free layer 504 (e.g., a sensing layer) having a magnetically free magnetization (e.g., a magnetic vortex). The external magnetic field may be a uniform magnetic field extending through both the magnetoresistive sensor 302 and the magnetoresistive sensor 502.

[0077] The magnetoresistive sensor 502 may be similar to the magnetoresistive sensor 302, having a similar layer stack and having similar magnetization within the layers of the layer stack. For example, the magnetoresistive sensor 302 and the magnetoresistive sensor 502 may each have a magnetic vortex free layer and a magnetic reference layer, and the magnetic reference layer has a fixed reference magnetization aligned with the same in-plane axis (e.g., the x-axis or the y-axis). Since the fixed reference magnetization defines the sensitive axis of the magnetoresistive sensor, the magnetoresistive sensor 302 and the magnetoresistive sensor 502 may both have sensitive axes aligned with the same in-plane axis. As a result, both the magnetoresistive sensor 302 and the magnetoresistive sensor 502 are insensitive to out-of-plane magnetic fields.

[0078] In summary, the magnetoresistive sensor 302 can have a first sensitive axis, and the magnetically free layer 306 can have a first magnetically free magnetization that is variable in the presence of an in-plane magnetic field aligned with the first sensitive axis. The magnetoresistive sensor 502 can have a second sensitive axis, and the magnetically free layer 504 can have a second magnetically free magnetization that is variable in the presence of an in-plane magnetic field aligned with the second sensitive axis. In some embodiments, the first sensitive axis and the second sensitive axis are aligned with the same in-plane axis (e.g., the x-axis or the y-axis). Figure 5 In the example shown in , the first sensitive axis and the second sensitive axis are aligned with the x-axis.

[0079] The ferromagnetic disk 304 has magnetic eddy currents configured to react to an out-of-plane magnetic field (or an out-of-plane magnetic field component) and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk 304. The in-plane magnetic field component of the stray field may be aligned with the first sensitive axis of the magnetoresistive sensor 302.

[0080] The magnetoresistive sensor 302 can be arranged in the stray field to receive the in-plane magnetic field component of the stray field generated according to the out-of-plane magnetic field. Therefore, the magnetic free magnetization of the magnetoresistive sensor 302 can be configured to change based on the in-plane magnetic field component of the stray field. However, since the magnetoresistive sensor 302 will receive both the external magnetic field (having its own in-plane magnetic field or in-plane magnetic field component) and the in-plane magnetic field component of the stray field, the magnetic free magnetization of the magnetic free layer 306 can react to both the external magnetic field and the in-plane magnetic field component of the stray field. In the case where the magnetic free magnetization of the magnetic free layer 306 reacts to both the external magnetic field and the in-plane magnetic field component of the stray field, when the sensor value of the magnetoresistive sensor 302 is read out, the in-plane magnetic field component of the stray field will not be distinguishable from the in-plane magnetic field component of the external magnetic field. As a result, the out-of-plane magnetic field (or out-of-plane magnetic field component) of the external magnetic field cannot be measured based only on the magnetoresistive sensor 302.

[0081] Since the stray field decays as the distance from the ferromagnetic disk 304 increases, the magnetoresistive sensor 502 can be arranged at a sufficient distance from the ferromagnetic disk 304 so that the magnetoresistive sensor 502 is outside the stray field. In other words, the magnetoresistive sensor 502 can be arranged in the external magnetic field so that the magnetoresistive sensor 502 responds to the in-plane magnetic field component of the external magnetic field, but is arranged outside the stray field so that the magnetoresistive sensor 502 does not respond to the in-plane magnetic field component of the stray field. In other words, the magnetic free magnetization of the magnetic free layer 504 can only respond to the in-plane magnetic field component of the external magnetic field. In some embodiments, the magnetoresistive sensor 302 and the magnetoresistive sensor 502 can be arranged at the same lateral side of the ferromagnetic disk 304, with different lateral distances from the ferromagnetic disk 304.

[0082] The magnetoresistive sensor 302 has a first resistance (or a first conductance) that changes based on a change in the magnetic free layer 306. The magnetoresistive sensor 502 has a second resistance (or a second conductance) that changes based on a change in the magnetic free layer 504. The magnetic free layer 306 is configured to change based on the in-plane magnetic field component of the external magnetic field and the in-plane magnetic field component of the stray field so that the first resistor has a first resistance component corresponding to the in-plane magnetic field component of the stray field and has a second resistance component corresponding to the in-plane magnetic field component of the external magnetic field. The magnetic free layer 504 is configured to change based only on the in-plane magnetic field component of the external magnetic field so that the total resistance of the second resistor corresponds to the in-plane magnetic field component of the external magnetic field.

[0083] The magnetic sensor system 500 also includes a Figure 1The sensor circuit described similarly, the sensor circuit is configured to measure the first resistance and the second resistance so that the second resistance component is offset by the second resistance. For example, the sensor circuit can subtract the second resistance from the first resistance so that only the first resistance component of the first resistance remains. In this way, the sensor value corresponding only to the in-plane magnetic field component of the stray field can be isolated from the influence of the in-plane magnetic field component of the external magnetic field. Therefore, the sensor circuit can be configured to generate a sensor signal representing only the first resistance component corresponding to the in-plane magnetic field component of the stray field (which is proportional to the out-of-plane component of the external magnetic field).

[0084] In some embodiments, the magnetic sensor system 500 can be used as a two-dimensional (2D) sensor or a three-dimensional (3D) sensor. The magnetoresistive sensor 302 can be referred to as an out-of-plane sensor or a z-sensor because the magnetoresistive sensor 302 is used to measure the out-of-plane component (e.g., Bz) of the external magnetic field. The magnetoresistive sensor 502 can be used to measure the in-plane component (e.g., Bx) of the external magnetic field. In other words, when the sensitive axis of the magnetoresistive sensor 502 is aligned with the x-axis, the resistance of the magnetoresistive sensor 502 can be used as a sensor value of the x-magnetic field component Bx of the external magnetic field, or when the sensitive axis of the magnetoresistive sensor 502 is aligned with the y-axis, it is used as a sensor value of the y-magnetic field component By of the external magnetic field. Therefore, the magnetoresistive sensor 502 can be referred to as an in-plane sensor, an x-sensor, or a y-sensor because the magnetoresistive sensor 502 is used to measure the in-plane component (e.g., Bx or By) of the external magnetic field.

[0085] One or more magnetoresistive sensors may be added to measure the third dimension of the external magnetic field. For example, if the sensitive axis of magnetoresistive sensor 302 and the sensitive axis of magnetoresistive sensor 502 are aligned with the x-axis, two additional magnetoresistive sensors may be added whose sensitive axes are aligned with the y-axis. One of the additional magnetoresistive sensors used as an out-of-plane sensor for measuring Bz may be arranged within the stray field, and another of the additional magnetoresistive sensors used as an in-plane sensor for measuring By may be arranged outside the stray field, similar to magnetoresistive sensors 302 and 502. In some embodiments, only one magnetoresistive sensor arranged outside the stray field and having a sensitive axis aligned with the y-axis may be added to measure the y-magnetic field component By of the external magnetic field.

[0086] As mentioned above, Figure 5 Other examples can be found in reference Figure 5 Different than described. Figure 5 The number and arrangement of components shown in FIG. 5 are provided as examples. In practice, the magnetic sensor system 500 may include Figure 5 Additional components, fewer components, different components, or differently arranged components than those shown in FIG. Figure 5Two or more components shown in may be implemented in a single component, or Figure 5 The single components shown in can be implemented as multiple distributed components. Additionally or alternatively, one set of components (eg, one or more components) of the magnetic sensor system 500 can perform one or more functions described as being performed by another set of components of the magnetic sensor system 500.

[0087] Figure 6 2 shows an example of a magnetic sensor system 600 according to one or more embodiments. The magnetic sensor system 600 can be used to measure an external out-of-plane magnetic field (e.g., Bz) when an external in-plane magnetic field (e.g., Bx) is also present. The magnetic sensor system 600 can include a magnetoresistive sensor 302 and a ferromagnetic disk 304, such as in combination with Figure 3 The magnetic sensor system 300 is described. In addition, the magnetic sensor system 600 may include an additional magnetoresistive sensor 602, which includes a magnetically free layer 604 (e.g., a sensing layer) having a magnetically free magnetization (e.g., a magnetic vortex). The external in-plane magnetic field may be a uniform magnetic field extending through both the magnetoresistive sensor 302 and the magnetoresistive sensor 602.

[0088] An external out-of-plane magnetic field may be applied to the ferromagnetic disk 304, which has magnetic eddy currents configured to react to the out-of-plane magnetic field and generate a stray field in response to the external out-of-plane magnetic field applied to the ferromagnetic disk 304. The stray field is shown as having two lobes extending in opposite lateral directions from the ferromagnetic disk 304. Due to the linear stray field response of the magnetic eddy currents of the ferromagnetic disk 304, the two lobes are proportional to the external out-of-plane magnetic field.

[0089] Specifically, the stray field may have a first lobe 606 extending to the right side of the ferromagnetic disk 304 in a clockwise pattern, and a second lobe 608 extending to the left side of the ferromagnetic disk 304 in a counterclockwise pattern. The first lobe 606 has a first in-plane magnetic field component, and the first in-plane magnetic field component has a first vector in a first direction (e.g., a positive x-direction) aligned with the sensitive axis of the magnetoresistive sensor 302. In addition, the first lobe 606 and the first in-plane magnetic field component are proportional to the external out-of-plane magnetic field. The second lobe 608 has a second in-plane magnetic field component, and the second in-plane magnetic field component has a second vector in a second direction (e.g., a negative x-direction) aligned with the sensitive axis of the magnetoresistive sensor 602. In addition, the second lobe 608 and the second in-plane magnetic field component are proportional to the external out-of-plane magnetic field. Therefore, the first vector of the first in-plane magnetic field component is antiparallel to the second vector of the second in-plane magnetic field component.

[0090] The magnetoresistive sensor 302 and the magnetoresistive sensor 602 are located at opposite lateral sides of the ferromagnetic disk 304. For example, the magnetoresistive sensor 302 may be arranged at a position within the first lobe 606 of the stray field suitable for measuring a first in-plane magnetic field component, and the magnetoresistive sensor 602 may be arranged at a position within the second lobe 608 of the stray field suitable for measuring a second in-plane magnetic field component.

[0091] The magnetoresistive sensor 302 includes a first sensitive axis and a first magnetically free layer 306, the first magnetically free layer 306 having a first magnetically free magnetization, the first magnetically free magnetization being variable in the presence of an external in-plane magnetic field aligned with the first sensitive axis and a first in-plane magnetic field component of a stray field. In other words, the first magnetically free magnetization can respond to both the external in-plane magnetic field and the first in-plane magnetic field component of the stray field.

[0092] The magnetoresistive sensor 602 includes a second sensitive axis and a second magnetically free layer 604, the second magnetically free layer 604 having a second magnetically free magnetization, and the second magnetically free magnetization is variable in the presence of an external in-plane magnetic field aligned with the second sensitive axis and a second in-plane magnetic field component of a stray field. In other words, the second magnetically free magnetization can respond to both the external in-plane magnetic field and the second in-plane magnetic field component of the stray field.

[0093] The first sensitive axis of the magnetoresistive sensor 302 can be parallel to the second sensitive axis of the magnetoresistive sensor 602 so that the magnetoresistive sensor 302 and the magnetoresistive sensor 602 are sensitive to the same in-plane magnetic field component and react in the same manner to magnetic fields pointing in the same direction (e.g., the positive x-direction). For example, when an external in-plane magnetic field is applied to both the magnetoresistive sensor 302 and the magnetoresistive sensor 602, the external in-plane magnetic field extends through both the magnetoresistive sensor 302 and the magnetoresistive sensor 602 in the same direction (e.g., the positive x-direction). The magnetoresistive sensor 302 and the magnetoresistive sensor 602 can experience corresponding changes in resistance equal in magnitude caused by the external in-plane magnetic field. Therefore, when read out by the sensor circuit 610 (e.g., by subtraction or differential processing), the corresponding changes in resistance of the magnetoresistive sensor 302 and the magnetoresistive sensor 602 caused by the external in-plane magnetic field can be canceled or offset.

[0094] In contrast, magnetoresistive sensor 302 and magnetoresistive sensor 602 may be sensitive to the same in-plane magnetic field component, but react in opposite ways to magnetic fields oriented in opposite directions along the x-axis. Since the first in-plane magnetic field component and the second in-plane magnetic field component of the stray field point in opposite directions, magnetoresistive sensor 302 and magnetoresistive sensor 602 may experience corresponding changes in resistance caused by the stray field that are equal but opposite in sign. When a subtraction or differential process is applied to the sensor signals of magnetoresistive sensor 302 and magnetoresistive sensor 602, the corresponding changes in resistance caused by the stray field may be added together (e.g., because values ​​of opposite signs are subtracted). Therefore, magnetoresistive sensor 302 is arranged within the first in-plane magnetic field component of the stray field to detect a first vector, and magnetoresistive sensor 602 is arranged within the second in-plane magnetic field component of the stray field to detect a second vector. Although the magnetoresistive sensor 302 and the magnetoresistive sensor 602 can also respond to the external in-plane magnetic field, the resistance changes caused by the external in-plane magnetic field at the magnetoresistive sensor 302 and the magnetoresistive sensor 602 are cancelled by the sensor circuit 610. At the same time, the resistance changes caused by the two antiparallel vectors of the stray field at the magnetoresistive sensor 302 and the magnetoresistive sensor 602 are added together to provide a delta resistance value that is proportional to the external out-of-plane magnetic field and represents only the external out-of-plane magnetic field.

[0095] In summary, the magnetoresistive sensor 302 may have a first resistance that varies based on a change in the first magnetic free layer. The first resistor may have a first resistance component corresponding to a first in-plane magnetic field component of a stray field, and may have a second resistance component corresponding to an external in-plane magnetic field. The magnetoresistive sensor 602 may have a second resistance that varies based on a change in the second magnetic free layer. The second resistor may have a third resistance component corresponding to a second in-plane magnetic field component of a stray field, and may have a fourth resistance component corresponding to an external in-plane magnetic field. The sensor circuit 610 may be configured to measure the first resistance and the second resistance so that the second resistance component and the fourth resistance component are offset. Therefore, the sensor circuit 610 may generate a sensor signal representing the combined resistance of the first resistance component and the third resistance component, wherein the combined resistance is proportional to the out-of-plane magnetic field.

[0096] As mentioned above, Figure 6 Other examples can be found in reference Figure 6 Different than described. Figure 6 The number and arrangement of components shown in FIG. 6 are provided as examples. In practice, the magnetic sensor system 600 may include Figure 6 Additional components, fewer components, different components, or differently arranged components than those shown in FIG. Figure 6 Two or more components shown in may be implemented in a single component, or Figure 6 The single components shown in can be implemented as multiple distributed components. Additionally or alternatively, one set of components (eg, one or more components) of the magnetic sensor system 600 can perform one or more functions described as being performed by another set of components of the magnetic sensor system 600.

[0097] The following provides an overview of some aspects of the disclosure:

[0098] Aspect 1: A magnetic sensor system, comprising: a magnetoresistive sensor, comprising a magnetic free layer, the magnetic free layer having a sensing plane and a magnetic free magnetization arranged in the sensing plane, wherein the magnetic free magnetization is variable in the presence of an in-plane magnetic field aligned with the sensing plane; and a ferromagnetic disk, having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to: react to an out-of-plane magnetic field, and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has an in-plane magnetic field component proportional to the out-of-plane magnetic field, wherein the magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and wherein the magnetic free magnetization is configured to: change based on the in-plane magnetic field component of the stray field.

[0099] Aspect 2: The magnetic sensor system according to aspect 1, wherein the ferromagnetic disk is configured to: convert an out-of-plane magnetic field into a stray field having an in-plane magnetic field component.

[0100] Aspect 3: The magnetic sensor system according to any one of aspects 1-2, wherein the magnetic eddy current provides a linear response to the out-of-plane magnetic field, so that the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field.

[0101] Aspect 4: The magnetic sensor system according to any one of aspects 1-3, wherein the ferromagnetic disk generates an in-plane magnetic field component of the stray field according to the out-of-plane magnetic field based on a linear response function, and wherein based on the linear response function, the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field.

[0102] Aspect 5: A magnetic sensor system according to Aspect 4, wherein the aspect ratio between the thickness and the diameter of the ferromagnetic disk defines a linear range portion of the stray field, wherein the linear range portion of the stray field responds to an out-of-plane magnetic field in a linear manner based on a linear response function, and wherein the magnetic free layer responds to the linear range portion of the stray field in a linear manner.

[0103] Aspect 6: The magnetic sensor system according to any one of aspects 1-5, wherein the ferromagnetic disk is configured to redirect the out-of-plane magnetic field as a stray field into the sensing plane of the magnetic free layer so that the in-plane magnetic field component of the stray field is aligned in-plane with the sensing plane of the magnetic free layer.

[0104] Aspect 7: The magnetic sensor system according to any one of aspects 1-6, wherein the magnetoresistive sensor is a linear magnetoresistive sensor having a linear sensor response.

[0105] Aspect 8: The magnetic sensor system according to any one of aspects 1-7, wherein the out-of-plane magnetic field is orthogonal to the in-plane magnetic field component.

[0106] Aspect 9: The magnetic sensor system according to any one of aspects 1 to 8, wherein the magnetoresistive sensor is spatially separated from the ferromagnetic disk.

[0107] Aspect 10: The magnetic sensor system according to any one of aspects 1 to 9, wherein the magnetization of the ferromagnetic disk is a closed flux magnetization in a vortex state.

[0108] Aspect 11: A magnetic sensor system according to any one of Aspects 1-10, wherein the magnetoresistive sensor has conductance or resistance, and wherein the magnetoresistive sensor is configured to: exhibit a linear change in conductance or resistance proportional to the out-of-plane magnetic field based on a change in magnetic free magnetization of an in-plane magnetic field component in response to a stray field.

[0109] Aspect 12: The magnetic sensor system according to any one of aspects 1-11, wherein magnetic eddy currents are generated within the ferromagnetic disk based on the volume of the ferromagnetic disk, and wherein the linear stray field response of the magnetic eddy currents is defined by the aspect ratio of the ferromagnetic disk.

[0110] Aspect 13: The magnetic sensor system according to any one of aspects 1-12, wherein the ferromagnetic disk is configured to not generate a measurable stray field at the magnetoresistive sensor when no external magnetic field or an insubstantial external magnetic field is applied to the ferromagnetic disk.

[0111] Aspect 14: The magnetic sensor system according to any one of aspects 1-13, wherein the ferromagnetic disk is made of a soft ferromagnetic material.

[0112] Aspect 15: A magnetic sensor system comprising: a first magnetoresistive sensor having a first sensitive axis and a first magnetic free layer, the first magnetic free layer having a first magnetic free magnetization, the first magnetic free magnetization being variable in the presence of an in-plane magnetic field aligned with the first sensitive axis; a second magnetoresistive sensor having a second sensitive axis and a second magnetic free layer, the second magnetic free layer having a second magnetic free magnetization, the second magnetic free magnetization being variable in the presence of an in-plane magnetic field aligned with the second sensitive axis; and a ferromagnetic disk having a magnetic eddy current in a ground state, wherein the magnetic eddy current is configured to: react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field decays as the distance from the ferromagnetic disk increases, wherein the first magnetoresistive sensor is arranged within the stray field, and the second magnetoresistive sensor is arranged outside the stray field, wherein the stray field has an in-plane magnetic field component proportional to the out-of-plane magnetic field, wherein the first magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and wherein the first magnetic free magnetization is configured to: change based on the in-plane magnetic field component of the stray field.

[0113] Aspect 16: A magnetic sensor system according to Aspect 15, wherein the first magnetoresistive sensor has a first resistance, the first resistance changes based on changes in the first magnetic free layer, wherein the second magnetoresistive sensor has a second resistance, the second resistance changes based on changes in the second magnetic free layer, wherein the first magnetic free layer is configured to: change based on the stray field and the in-plane magnetic field so that the first resistance has a first resistance component corresponding to the in-plane magnetic field component of the stray field, and has a second resistance component corresponding to the in-plane magnetic field, wherein the second magnetic free layer is configured to: change based on the in-plane magnetic field so that the total resistance of the second resistance corresponds to the in-plane magnetic field, wherein the magnetic sensor system also includes a sensor circuit, the sensor circuit is configured to: measure the first resistance and the second resistance so that the second resistance component is offset by the second resistance, and wherein the sensor circuit is configured to generate a sensor signal, the sensor signal representing the first resistance component corresponding to the in-plane magnetic field component of the stray field.

[0114] Aspect 17: The magnetic sensor system according to any one of aspects 15-16, wherein the first magnetoresistive sensor and the second magnetoresistive sensor are arranged on a same lateral side of the ferromagnetic disk.

[0115] Aspect 18: A magnetic sensor system comprising: a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to: react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has a first in-plane magnetic field component and a second in-plane magnetic field component proportional to the out-of-plane magnetic field, and wherein the first in-plane magnetic field component has a first vector in a first direction and the second in-plane magnetic field component has a second vector in a second direction, the second direction being antiparallel to the first direction; a first magnetoresistive sensor having a first sensitive axis and a first magnetic free layer, the first magnetic free layer having a first sensitive axis. a magnetic free layer, the first magnetic free magnetization being variable in the presence of an external in-plane magnetic field aligned with a first sensitive axis; and a second magnetoresistive sensor having a second sensitive axis and a second magnetic free layer, the second magnetic free layer having a second magnetic free magnetization being variable in the presence of an external in-plane magnetic field aligned with a second sensitive axis, wherein the first sensitive axis is parallel to the second sensitive axis, wherein the first magnetoresistive sensor is arranged within the first in-plane magnetic field component of the stray field to detect the first vector, and wherein the second magnetoresistive sensor is arranged within the second in-plane magnetic field component of the stray field to detect the second vector.

[0116] Aspect 19: The magnetic sensor system according to aspect 18, wherein the first magnetoresistive sensor and the second magnetoresistive sensor are located at opposite lateral sides of the ferromagnetic disk.

[0117] Aspect 20: A magnetic sensor system according to any one of Aspects 18-19, wherein the external in-plane magnetic field is a uniform magnetic field, the uniform magnetic field extends through both the first magnetoresistive sensor and the second magnetoresistive sensor in the first direction or the second direction, wherein the first magnetic free magnetization is configured to change based on the first in-plane magnetic field component of the stray field and the external in-plane magnetic field, and wherein the second magnetic free magnetization is configured to change based on the second in-plane magnetic field component of the stray field and the external in-plane magnetic field.

[0118] Aspect 21: A magnetic sensor system according to any one of Aspects 18-20, wherein the first magnetoresistive sensor has a first resistance, the first resistance changes based on changes in the first magnetic free layer, wherein the first resistance has a first resistance component corresponding to a first in-plane magnetic field component of a stray field, and has a second resistance component corresponding to an external in-plane magnetic field, wherein the second magnetoresistive sensor has a second resistance, the second resistance changes based on changes in the second magnetic free layer, wherein the second resistance has a third resistance component corresponding to the second in-plane magnetic field component of the stray field, and has a fourth resistance component corresponding to the external in-plane magnetic field, wherein the magnetic sensor system also includes a sensor circuit, the sensor circuit is configured to: measure the first resistance and the second resistance so that the second resistance component and the fourth resistance component are offset, wherein the sensor circuit is configured to generate a sensor signal, the sensor signal represents a combined resistance of the first resistance component and the third resistance component, and wherein the combined resistance is proportional to the out-of-plane magnetic field.

[0119] Aspect 22: A system configured to perform one or more operations recited in one or more of Aspects 1-21.

[0120] Aspect 23: An apparatus comprising means for performing one or more operations recited in one or more of Aspects 1-21.

[0121] Aspect 24: A non-transitory computer-readable medium storing an instruction set, the instruction set comprising one or more instructions, which, when executed by a device, causes the device to perform one or more operations recited in one or more of Aspects 1-21.

[0122] Aspect 25: A computer program product comprising instructions or codes for performing one or more operations recited in one or more of Aspects 1-21.

[0123] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the embodiments.

[0124] Some embodiments may be described herein in conjunction with a threshold value. As used herein, "satisfying" a threshold value may refer to a value being greater than a threshold value, more than a threshold value, above a threshold value, greater than or equal to a threshold value, less than a threshold value, less than a threshold value, below a threshold value, less than or equal to a threshold value, equal to a threshold value, etc.

[0125] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, or a combination of hardware and software. The systems and / or methods described herein can be implemented in different forms of hardware, firmware, or a combination of hardware and software. The actual dedicated control hardware or software code used to implement these systems and / or methods does not limit these implementations. Therefore, the operation and behavior of the systems and / or methods are described herein without reference to specific software code - it should be understood that software and hardware can be designed to implement the systems and / or methods based on the description herein.

[0126] Any processing component can be implemented as a central processing unit (CPU), or other processors that read and execute software programs from non-transient computer-readable recording media (such as hard disks or semiconductor storage devices). For example, instructions can be executed by one or more processors, such as one or more CPUs, digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field programmable logic arrays (FPLAs), programmable logic controllers (PLCs), or other equivalent integrated or discrete logic circuits. Therefore, the term "processor" used herein refers to any of the aforementioned structures or any other structure suitable for implementing the technology described herein. The software can be stored on a non-transient computer-readable medium so that the non-transient computer-readable medium includes a program code or program algorithm stored thereon, which, when executed, causes the processor to perform the steps of the method via a computer program.

[0127] A controller including hardware may also perform one or more of the techniques of the present disclosure. A controller including one or more processors may use electrical signals and digital algorithms to perform its reception, analysis, and control functions, which may also include correction functions. Such hardware, software, and firmware may be implemented in the same device or in separate devices to support the various techniques described in the present disclosure.

[0128] Signal processing circuitry and / or signal conditioning circuitry may receive one or more signals (e.g., measurement signals) in the form of raw measurement data from one or more components, and may derive further information from the measurement signals. As used herein, "signal conditioning" refers to manipulating an analog signal in a manner such that the signal meets the requirements of the next stage for further processing. Signal conditioning may include conversion from analog to digital (e.g., via an analog-to-digital converter), amplification, filtering, conversion, biasing, range matching, isolation, and any other process required to make the signal suitable for processing after conditioning.

[0129] Although the specific combination of features is described in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the embodiments described herein. Many of these features can be combined in a manner that is not specifically described in the claims and / or not specifically disclosed in the specification. For example, the disclosure includes a combination of each dependent claim in the claim set with each other individual claim in the claim set, and includes each combination of multiple claims in the claim set. As used herein, the phrase "at least one" of the reference list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b or c" is intended to cover a, b, c, a and b, a and c, b and c, and a, b and c, and any combination of multiples of the same element (e.g., a+a, a+a+a, a+a+b, a+a+c, a+b+b, a+c+c, b+b, b+b+b, b+b+c, c+c and c+c+c, or any other order of a, b and c).

[0130] In addition, it should be understood that the disclosure of multiple actions or functions disclosed in the specification or claims cannot be interpreted as being in a specific order. Therefore, the disclosure of multiple actions or functions does not limit them to a specific order unless these actions or functions are not interchangeable for technical reasons. In addition, in some embodiments, a single action may include or may be divided into multiple sub-actions. Unless explicitly excluded, such sub-actions may be included and become part of the disclosure of the single action.

[0131] Any element, action or instruction used in this article should not be interpreted as key or necessary unless explicitly described as such. In addition, as used in this article, the articles "one" and "a" are intended to include one or more items, and can be used interchangeably with "one or more". In addition, as used in this article, the article "the" is intended to include one or more items related to the article "the", and can be used interchangeably with "one or more". If only one project is referred to, the phrase "only one", "single" or similar language is used. In addition, as used in this article, the terms "include", "comprise", "have" etc. are intended to be open terms, which do not limit the elements they modify (for example, "elements with" A can also have B). In addition, the phrase "based on" is intended to mean "at least partially based on", unless otherwise clearly stated. As used in this article, the term "multiple (multiple)" can be replaced by "multiple (a plurality of)", and vice versa. In addition, as used in this article, the term "or" is intended to be inclusive when used in series, and can be used interchangeably with "and / or", unless otherwise clearly stated (for example, if used in combination with "either" or "only one").

Claims

1. A magnetic sensor system, comprising: A magnetoresistive sensor comprising a magnetically free layer having a sensing plane and a magnetically free magnetization disposed within the sensing plane, wherein the magnetically free magnetization is variable in the presence of an in-plane magnetic field aligned with the sensing plane; and a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has an in-plane magnetic field component that is proportional to the out-of-plane magnetic field, wherein the magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and wherein the magnetic free magnetization is configured to change based on the in-plane magnetic field component of the stray field. 2 . The magnetic sensor system of claim 1 , wherein the ferromagnetic disk is configured to convert the out-of-plane magnetic field into the stray field having the in-plane magnetic field component. 3 . The magnetic sensor system of claim 1 , wherein the magnetic eddy currents provide a linear response to the out-of-plane magnetic field so that the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field.

4. The magnetic sensor system according to claim 1 , wherein the ferromagnetic disk generates the in-plane magnetic field component of the stray field according to the out-of-plane magnetic field based on a linear response function, and Based on the linear response function, the in-plane magnetic field component of the stray field has a linear relationship with the out-of-plane magnetic field.

5. The magnetic sensor system of claim 4, wherein an aspect ratio between the thickness and the diameter of the ferromagnetic disk defines a linear range portion of the stray field, wherein the linear range of the stray field responds to the out-of-plane magnetic field in a linear manner based in part on the linear response function, and The magnetically free layer responds in a linear manner to the linear range portion of the stray field.

6. The magnetic sensor system of claim 1 , wherein the ferromagnetic disk is configured to redirect the out-of-plane magnetic field as the stray field into the sensing plane of the magnetically free layer so that the in-plane magnetic field component of the stray field is aligned in-plane with the sensing plane of the magnetically free layer. 7 . The magnetic sensor system of claim 1 , wherein the magnetoresistive sensor is a linear magnetoresistive sensor having a linear sensor response.

8. The magnetic sensor system of claim 1, wherein the out-of-plane magnetic field is orthogonal to the in-plane magnetic field component.

9. The magnetic sensor system of claim 1, wherein the magnetoresistive sensor is spatially separated from the ferromagnetic disk. 10 . The magnetic sensor system of claim 1 , wherein the magnetization of the ferromagnetic disk is a closed flux magnetization in a vortex state.

11. The magnetic sensor system according to claim 1, wherein the magnetoresistive sensor has conductance or resistance, and The magnetoresistive sensor is configured to exhibit a linear change in the conductance or the resistance based on a change in the magnetic free magnetization in response to the in-plane magnetic field component of the stray field, the linear change being proportional to the out-of-plane magnetic field.

12. The magnetic sensor system according to claim 1, wherein the magnetic eddy current is generated in the ferromagnetic disk based on the volume of the ferromagnetic disk, and The linear stray field response of the magnetic eddy currents is defined by the aspect ratio of the ferromagnetic disk.

13. The magnetic sensor system of claim 1, wherein the ferromagnetic disk is configured to not generate a measurable stray field at the magnetoresistive sensor when no external magnetic field is applied to the ferromagnetic disk or when an insubstantial external magnetic field is applied to the ferromagnetic disk.

14. The magnetic sensor system of claim 1, wherein the ferromagnetic disk is made of a soft ferromagnetic material.

15. A magnetic sensor system comprising: a first magnetoresistive sensor having a first sensitive axis and a first magnetically free layer, the first magnetically free layer having a first magnetically free magnetization that is variable in the presence of an in-plane magnetic field aligned with the first sensitive axis; a second magnetoresistive sensor having a second sensitive axis and a second magnetically free layer, the second magnetically free layer having a second magnetically free magnetization that is variable in the presence of the in-plane magnetic field aligned with the second sensitive axis; and a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field decays with increasing distance from the ferromagnetic disk, wherein the first magnetoresistive sensor is arranged within the stray field, and the second magnetoresistive sensor is arranged outside the stray field, wherein the stray field has an in-plane magnetic field component that is proportional to the out-of-plane magnetic field, wherein the first magnetic free layer is configured to: receive the in-plane magnetic field component of the stray field, and The first magnetic free magnetization is configured to change based on the in-plane magnetic field component of the stray field.

16. The magnetic sensor system of claim 15 , wherein the first magnetoresistive sensor has a first resistance that changes based on a change in the first magnetic free layer, wherein the second magnetoresistive sensor has a second resistance that changes based on a change in the second magnetic free layer, wherein the first magnetic free layer is configured to change based on the stray field and the in-plane magnetic field so that the first resistor has a first resistance component corresponding to the in-plane magnetic field component of the stray field and has a second resistance component corresponding to the in-plane magnetic field, wherein the second magnetic free layer is configured to change based on the in-plane magnetic field so that the total resistance of the second resistor corresponds to the in-plane magnetic field, The magnetic sensor system further comprises a sensor circuit configured to: measure the first resistance and the second resistance so that the second resistance component is offset by the second resistance, and Wherein the sensor circuit is configured to generate a sensor signal representing the first resistance component corresponding to the in-plane magnetic field component of the stray field. 17 . The magnetic sensor system of claim 15 , wherein the first magnetoresistive sensor and the second magnetoresistive sensor are arranged at a same lateral side of the ferromagnetic disk.

18. A magnetic sensor system comprising: a ferromagnetic disk having magnetic eddy currents in a ground state, wherein the magnetic eddy currents are configured to: react to an out-of-plane magnetic field and generate a stray field in response to the out-of-plane magnetic field applied to the ferromagnetic disk, wherein the stray field has a first in-plane magnetic field component and a second in-plane magnetic field component proportional to the out-of-plane magnetic field, and wherein the first in-plane magnetic field component has a first vector in a first direction and the second in-plane magnetic field component has a second vector in a second direction, the second direction being antiparallel to the first direction; a first magnetoresistive sensor having a first sensitive axis and a first magnetically free layer, the first magnetically free layer having a first magnetically free magnetization that is variable in the presence of an external in-plane magnetic field aligned with the first sensitive axis; as well as a second magnetoresistive sensor having a second sensitive axis and a second magnetically free layer, the second magnetically free layer having a second magnetically free magnetization that is variable in the presence of the external in-plane magnetic field aligned with the second sensitive axis, wherein the first sensitive axis is parallel to the second sensitive axis, wherein the first magnetoresistive sensor is arranged in the first in-plane magnetic field component of the stray field to detect the first vector, and The second magnetoresistive sensor is arranged in the second in-plane magnetic field component of the stray field to detect the second vector. 19 . The magnetic sensor system of claim 18 , wherein the first magnetoresistive sensor and the second magnetoresistive sensor are located at opposite lateral sides of the ferromagnetic disk.

20. The magnetic sensor system of claim 18, wherein the external in-plane magnetic field is a uniform magnetic field that extends through both the first magnetoresistive sensor and the second magnetoresistive sensor in the first direction or the second direction, wherein the first magnetic free magnetization is configured to change based on the first in-plane magnetic field component of the stray field and the external in-plane magnetic field, and The second magnetic free magnetization is configured to change based on the second in-plane magnetic field component of the stray field and the external in-plane magnetic field.

21. The magnetic sensor system of claim 18, wherein the first magnetoresistive sensor has a first resistance that changes based on a change in the first magnetic free layer, wherein the first resistor has a first resistance component corresponding to the first in-plane magnetic field component of the stray field, and has a second resistance component corresponding to the external in-plane magnetic field, wherein the second magnetoresistive sensor has a second resistance that changes based on a change in the second magnetic free layer, wherein the second resistor has a third resistance component corresponding to the second in-plane magnetic field component of the stray field, and has a fourth resistance component corresponding to the external in-plane magnetic field, The magnetic sensor system further comprises a sensor circuit, wherein the sensor circuit is configured to: measure the first resistance and the second resistance so that the second resistance component and the fourth resistance component are offset; wherein the sensor circuit is configured to generate a sensor signal representing a combined resistance of the first resistance component and the third resistance component, and Wherein the combined resistance is proportional to the out-of-plane magnetic field.

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