Magnetic sensor

Abstract

A magnetic sensor according to the present invention comprises: a magnetic detection element (magnetoresistance effect element 10a, Hall element 10h) having a magnetosensitive portion having a sensitivity axis along a first direction (X-direction); and a magnetic anisotropy control unit 60 that reversibly changes the measurement sensitivity of the magnetosensitive portion. The magnetic anisotropy control unit 60 aligns the magnetic anisotropy of the magnetosensitive portion along a second direction (Y-direction) different from the first direction (X-direction) on the basis of a spin-orbit torque generated by energization, thereby allowing a measurement range (dynamic range) to be expanded. The magnetic anisotropy control unit 60 may also include a spin Hall unit 20 capable of generating the spin-orbit torque in response to energization, and a magnetic switching unit 40 magnetically coupled to the magnetosensitive portion and having magnetic anisotropy which is reversibly aligned along the second direction (Y-direction) on the basis of the spin-orbit torque generated by the spin Hall unit 20.

Description

Magnetic sensor

[0001] The present invention relates to a magnetic sensor having a wide measurable range (dynamic range) of the intensity of an external magnetic field.

[0002] Examples of magnetic sensors that detect and measure magnetic fields include magnetic sensing elements provided with magnetoresistive effect elements using the GMR (Giant Magnetoresistive) effect or the TMR (Tunnel Magnetoresistive) effect, and magnetic sensing elements composed of Hall elements.

[0003] In Patent Document 1, for the purpose of providing a thin-film magnetic sensor using a GMR film that can simultaneously measure both high magnetic fields and low magnetic fields with appropriate resolution, a thin-film magnetic sensor is disclosed that includes a GMR film having a giant magnetoresistive effect, a first thin-film yoke made of a first soft magnetic material electrically connected to one end of the GMR film, and a second thin-film yoke made of a second soft magnetic material electrically connected to the other end of the GMR film, wherein the apparent permeability of the first thin-film yoke is different from that of the second thin-film yoke.

[0004] Japanese Unexamined Patent Application Publication No. 2009-229380

[0005] In the thin-film magnetic sensor disclosed in Patent Document 1, a plurality of yokes having different apparent permeability due to different saturation magnetic flux densities are arranged around the GMR film, so that the magnetic flux collecting function of the plurality of yokes as a whole is enhanced in a low magnetic field and reduced in a high magnetic field, thereby enabling measurement of both high magnetic fields and low magnetic fields.

[0006] An object of the present invention is to provide a magnetic sensor having a wide measurable range (dynamic range) of the intensity of an external magnetic field based on a principle different from that of the prior art.

[0007] In one embodiment, the present invention provides a magnetic sensor comprising a magnetic sensing element having a magnetic sensing portion whose sensitivity axis is aligned with a first direction, and a magnetic anisotropy control unit that reversibly changes the measurement sensitivity of the magnetic sensing portion, wherein the magnetic anisotropy control unit aligns the magnetic anisotropy of the magnetic sensing portion with a second direction different from the first direction based on a spin orbit torque generated by energization. By aligning the magnetic anisotropy of the magnetic sensing portion with the second direction, the ease with which the magnetic moment in the magnetic sensing portion rotates when subjected to a measurement magnetic field in the first direction can be changed. This makes it possible to change the effective sensitivity of the magnetic sensing portion to the measurement magnetic field, thereby expanding the measurement range of the magnetic sensor.

[0008] In the magnetic sensor described above, the magnetic anisotropy control unit may change the degree of magnetic anisotropy of the magnetic sensing element by controlling the energization. This makes it possible to change the effective sensitivity of the magnetic sensing element to the measuring magnetic field by controlling the energization, and enables control of the measurement range of the magnetic sensor by energizing the magnetic anisotropy control unit.

[0009] In the magnetic sensor described above, the magnetic anisotropy control unit may include a spin Hall portion capable of generating the spin orbit torque in response to current flow, and a magnetic switching portion that is magnetically coupled to the magnetosensitive portion and causes the magnetic anisotropy to reversibly align in the second direction based on the spin orbit torque generated by the spin Hall portion. Based on the spin orbit torque generated by current flowing to the spin Hall portion, the magnetic switching portion generates a bias magnetic field that causes the magnetic anisotropy of the magnetosensitive portion to align in the second direction. Since the strength of this bias magnetic field has a positive correlation with the amount of current flowing to the magnetic anisotropy control unit, the effective sensitivity of the magnetosensitive portion to the measuring magnetic field can be changed by adjusting the amount of current flowing to the magnetic anisotropy control unit, and as a result, the measurement range of the magnetic sensor can be controlled by current flow.

[0010] In the magnetic sensor described above, the magnetic switching unit may be integrated with the magnetic sensing unit.

[0011] In the magnetic sensor described above, the magnetic anisotropy control unit is magnetically coupled to the magnetosensitive unit and capable of generating the spin-orbit torque in response to current application. It may also have a magnetic anisotropy spin Hall portion in which the magnetic anisotropy is reversibly aligned in the second direction based on the generated spin-orbit torque. Alternatively, the magnetosensitive unit may be an integral part of the magnetic anisotropy control unit.

[0012] In the magnetic sensor described above, the magnetic anisotropy control unit may further include a bias magnetic field source that directs the magnetic anisotropy of the magnetic sensing portion to a third direction different from the first direction when the magnetic anisotropy control unit is not energized. In this case, the relationship between the second direction and the third direction is arbitrary, the third direction may be aligned with the second direction, and the first direction, the second direction and the third direction may be orthogonal to each other.

[0013] The magnetic sensor equipped with the bias magnetic field source described above further comprises a portion made of an antiferromagnetic material, and the exchange coupling interaction between the antiferromagnetic portion and the magnetic material may serve as the bias magnetic field source. In this case, the magnetic anisotropy control unit may also include the portion made of the antiferromagnetic material.

[0014] According to the present invention, it is possible to align the magnetic anisotropy of the magnetosensitive part to a predetermined direction (first direction) without applying an external magnetic field.

[0015] This is a block diagram of a magnetic sensor according to one embodiment of the present invention. This is an explanatory diagram of a full-bridge circuit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the non-energized state in the first example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the first energized state in the first example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the second energized state in the first example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the non-energized state in the second example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the first energized state in the second example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the second energized state in the second example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the non-energized state in the third example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the first energized state in the third example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating the second energized state in the third example of the individual magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. This figure illustrates a first modified example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention (where the spin Hall unit and the magnetic switching unit are integrated). This figure illustrates a second modified example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention (where the magnetic switching unit and the free magnetic layer are integrated). This figure illustrates a third modified example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention (where the magnetic anisotropy control unit and the free magnetic layer are integrated). This figure illustrates the non-energized state in the first example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. This figure illustrates the first energized state in the first example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. This figure illustrates the second energized state in the first example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. This figure illustrates the non-energized state in the second example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. This figure illustrates the first energized state in the second example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention.This figure illustrates a second energized state in a second example of the magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention. This figure illustrates a second energized state in a modified example of the second example of the individual magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention. This figure illustrates a non-energetic state in a third example of the magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention. This figure illustrates a first energized state in a third example of the magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention. This figure illustrates a second energized state in a third example of the magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention. This figure illustrates a first modified example of the individual magnetic field detection unit of a magnetic sensor according to a second embodiment of the present invention (where the spin Hall unit and the magnetic switching unit are integrated). This figure illustrates a second modified example of the individual magnetic field detection unit of a magnetic sensor according to a first embodiment of the present invention (where the magnetic switching unit and the Hall element are integrated). This figure illustrates a third modified example of the individual magnetic field detection unit of a magnetic sensor according to a first embodiment of the present invention (where the magnetic anisotropy control unit and the Hall element are integrated).

[0016] Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same component is given the same number, and its description is omitted. Reference coordinates are shown in each drawing as appropriate to indicate the positional relationship of each component. The reference coordinates are defined by three mutually orthogonal directions (X direction, Y direction, and Z direction), and the orientation of each direction is expressed as X1 direction (X direction X1 direction). In this specification, the direction in which the measurement magnetic field H is applied is also referred to as the "first direction".

[0017] Furthermore, in this specification, the direction of magnetic anisotropy in the magnetic anisotropy control unit (details described later) when current is applied to the magnetic anisotropy control unit and the measuring magnetic field H is not applied to the magnetic sensor is referred to as the "second direction." The direction of magnetic anisotropy when current is not applied to the magnetic anisotropy control unit (details described later) and the measuring magnetic field H is not applied to the magnetic sensor (hereinafter, this state may be abbreviated as the "non-energized state") is referred to as the "third direction." The second and third directions intersect with the first direction and, in one example, are perpendicular to the first direction. Depending on the method of setting the magnetic anisotropy in the magnetic anisotropy control unit, the second and third directions may be parallel or intersect with each other.

[0018] (First Embodiment) Figure 1 is a block diagram of a magnetic sensor according to one embodiment of the present invention. Figure 2 is an explanatory diagram of the full-bridge circuit included in the magnetic sensor according to the first embodiment of the present invention. The magnetic sensor 1 of this embodiment includes a magnetic field detection unit 2, a power supply unit 3, a magnetic field calculation unit 4 and an amplifier 5, an analog-to-digital conversion circuit (A / D conversion circuit 6) and a control unit 7. The control unit 7 controls each part that constitutes the magnetic sensor 1 and is configured as a CPU (central processing unit) and a program, etc.

[0019] The magnetic field detection unit 2 detects the external magnetic field to be measured (measured magnetic field H), and as shown in Figure 2, it has four individual magnetic field detection units 100a, 100b, 100c, and 100d. Individual magnetic field detection unit 100a has a magnetoresistive element 10a, individual magnetic field detection unit 100b has a magnetoresistive element 10b, individual magnetic field detection unit 100c has a magnetoresistive element 10c, and individual magnetic field detection unit 100d has a magnetoresistive element 10d. The magnetoresistive elements 10a, 10b, 10c, and 10d constitute a full-bridge circuit 15, and the magnetic field detection unit 2 measures the magnetic field along the X direction. The power supply unit 3 applies a predetermined current or a predetermined voltage to each unit based on a control signal from the control unit 7.

[0020] The magnetic field calculation unit 4 calculates the measured magnetic field H based on the output of the magnetic field detection unit 2. In the magnetic sensor 1, after the magnetic field calculation unit 4 calculates the measured magnetic field H, the signal corresponding to the calculated measured magnetic field H is amplified by the amplifier 5 and then converted into digital data by the A / D conversion circuit 6.

[0021] The four magnetoresistive elements 10a, 10b, 10c, and 10d in the magnetic field detection unit 2 of the magnetic sensor 1 according to one embodiment of the present invention may be provided on the same substrate (one chip). In this embodiment, the four magnetoresistive elements 10a, 10b, 10c, and 10d are provided on the same substrate (not shown) in Figure 2, and Figure 2 is a view of the magnetic field detection unit 2 of the magnetic sensor 1 as seen from the laminated surface (front surface) of the substrate in the direction normal to the substrate. That is, in Figure 2, the Z1 side is the front surface of the substrate, and the Z2 side is the back surface of the substrate. The Z direction is along the lamination direction of the magnetoresistive elements 10a, 10b, 10c, and 10d.

[0022] The magnetic field detection unit 2 has a full bridge circuit 15 in which a first half-bridge circuit, in which magnetoresistive elements 10a and 10b, both extending in the Y direction, are connected in series between the power supply terminal Vdd, which is the power supply point from the measurement power supply provided by the power supply unit 3, and the ground terminal GND, and a second half-bridge circuit, in which magnetoresistive elements 10c and 10d, both extending in the Y direction, are connected in series, are connected in parallel.

[0023] The first half-bridge circuit has an output terminal V1 between magnetoresistive elements 10a and 10b. The second half-bridge circuit has an output terminal V2 between magnetoresistive elements 10c and 10d. The potential difference between these two output terminals V1 and V2 (midpoint potential Va of the first half-bridge circuit - midpoint potential Vb of the second half-bridge circuit) allows for the quantitative measurement of the magnitude of an externally applied magnetic field H as the measurement magnetic field. In this embodiment, a first signal including the midpoint potential Va from output terminal V1 and a second signal including the midpoint potential Vb from output terminal V2 are output from the magnetic field detection unit 2, and the processing performed by the magnetic field calculation unit 4 includes calculating the midpoint potential difference using these first and second signals as input.

[0024] The magnetization fixed layer 11 (see Figure 3) of the pair of magnetoresistive elements 10a and 10b forming the first half-bridge circuit can maintain its magnetization 11m in a predetermined direction even when subjected to a measurement magnetic field H within the measurement range. Specifically, the magnetization 11m of the magnetization fixed layer 11 is oriented X2 with respect to magnetoresistive element 10a and X1 with respect to magnetoresistive element 10b, along the X direction which is the direction in which the measurement magnetic field H is applied (first direction), as shown by the white arrows in Figure 2. Similarly, in the pair of magnetoresistive elements 10c and 10d forming the second half-bridge circuit, the magnetization 11m of the magnetization fixed layer 11 is oriented X1 with respect to magnetoresistive element 10c and X2 with respect to magnetoresistive element 10d, as shown by the white arrows in Figure 2. Note that in Figure 2, the measurement magnetic field H has not yet been applied and is in a no-magnetic-field state, so the measurement magnetic field H is shown by a dashed arrow. The same applies to subsequent drawings.

[0025] In the first half-bridge circuit and the second half-bridge circuit, the magnetization 11m of the magnetization fixed layer 11 of the magnetoresistive element 10b on the power terminal Vdd side and the magnetization 11m of the magnetoresistive element 10d on the power terminal Vdd side are in opposite directions (antiparallel). Also, the magnetization 11m of the magnetoresistive element 10a on the ground terminal GND side and the magnetization 11m of the magnetoresistive element 10c on the power terminal GND side are in opposite directions (antiparallel). Therefore, the sensitivity axis direction of the magnetoresistive elements 10a, 10b, 10c, and 10d is all in the X direction (first direction).

[0026] Furthermore, in the four magnetoresistive elements 10a, 10b, 10c, and 10d, the direction of the magnetization 13m of the free magnetic layer 13 (see Figure 3) is the same when no measurement magnetic field H is applied, and it is aligned with the Y2 direction, as shown by the black arrow in Figure 2. When the free magnetic layer 13 receives a measurement magnetic field H in the first direction (X direction), it can be magnetized in a direction aligned with the measurement magnetic field H. In the magnetoresistive elements 10a, 10b, 10c, and 10d according to one aspect of the present invention, the direction of the magnetization 13m of the free magnetic layer 13 in a no-magnetic-field state when no measurement magnetic field H is applied is aligned with the Y2 direction, which is perpendicular to the direction of the magnetization 11m of the magnetization fixed layer 11, by the bias magnetic field. As a result, the hysteresis in measuring the measurement magnetic field H is reduced in the magnetoresistive elements 10a, 10b, 10c, and 10d. Furthermore, in order for the magnetization 13m of the free magnetic layer 13 to rotate in the first direction when the measurement magnetic field H is applied, the strength of the measurement magnetic field H must be high enough to exceed the strength of the bias magnetic field applied to align the magnetization 13m of the free magnetic layer 13 in the Y2 direction.

[0027] With the above configuration, as the magnitude of the measured magnetic field H in the X direction changes, the outputs from the output terminal V1 of the first half-bridge circuit and the output terminal V2 of the second half-bridge circuit change in opposite directions. Therefore, a large output is obtained as the potential difference (Va - Vb) between the two output terminals V1 and V2. Thus, the magnetic sensor 1 can detect the measured magnetic field H with high precision. In addition, the first half-bridge circuit or the second half-bridge circuit can be used instead of the full-bridge circuit 15, or the magnetoresistive element 10a can be used alone.

[0028] (First Example) Figure 3 is a diagram illustrating the non-energized state in the first example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 4 is a diagram illustrating the first energized state in the first example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 5 is a diagram illustrating the second energized state in the first example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figures 3 to 5 correspond to the XZ cross-sectional view along the line A-A' in Figure 2. Note that the amount of current (energy flow) of the control current 20c applied to the magnetic anisotropy control unit 60 differs between the first energized state and the second energized state, as will be described later, with the energy flow being greater in the second energized state than in the first energized state.

[0029] Each individual magnetic field detection unit 100a comprises a magnetoresistive element 10a, which is a film-like body formed on a substrate, and a magnetic anisotropy control unit 60. The magnetoresistive element 10a has a free magnetic layer 13, which is a magnetosensitive part that can be magnetized in a first direction with the first direction along the measured magnetic field H as the sensitivity axis, a magnetization-fixing layer 11 that can maintain a state in which the magnetization 11m is aligned with the first direction (X direction) in Figure 3, and a non-magnetic layer 12 located between the free magnetic layer 13 and the magnetization-fixing layer 11, and exhibits a magnetoresistive effect.

[0030] The magnetic anisotropy control unit 60 is a component that reversibly changes the measurement sensitivity of the magnetosensitive part (free magnetic layer 13), and specifically, it aligns the magnetic anisotropy of the magnetosensitive part (free magnetic layer 13) when no measurement magnetic field H is applied with a second direction (Y direction) perpendicular to the first direction.

[0031] The magnetoresistive element 10a can measure the strength of the measurement magnetic field H applied to the free magnetic layer 13, which is the magnetosensitive part, by detecting the resistance value caused by the misalignment of the magnetization direction between the free magnetic layer 13 sandwiching the non-magnetic layer 12 and the magnetization fixed layer 11.

[0032] The magnetization fixed layer 11 is constructed using a magnetic material such as a CoFe alloy (cobalt-iron alloy). The non-magnetic layer 12 is an insulating barrier layer made of, for example, MgO, Al2O3, or titanium oxide, when the magnetoresistive element 10a is a tunnel magnetoresistive element (TMR). The free magnetic layer 13 is constructed using a soft magnetic material such as a CoFe alloy or NiFe alloy (nickel-iron alloy). The magnetization fixed layer 11 and the free magnetic layer 13 may be single-layer or multilayer structures. In the case of a multilayer structure, it is preferable to have a multilayer ferristructure. When the magnetoresistive element 10a is a giant magnetoresistive element (GMR), a non-magnetic material such as Cu is used as the constituent material of the non-magnetic layer 12. In this embodiment, the free magnetic layer 13 is located on the Z2 side of the magnetoresistive element 10a, and the detection center 10P of the magnetoresistive element 10a is located at the center of the free magnetic layer 13.

[0033] In this embodiment, the magnetoresistive element 10a of the individual magnetic field detection unit 100a is, as a specific example, a tunnel magnetoresistive element (TMR). For the purpose of measuring the electrical characteristics of the magnetoresistive element 10a, measurement wiring 62 is provided so that a voltage from a measurement power supply is applied in a third direction (Z direction) between the free magnetic layer 13 and the magnetization fixed layer 11 of the magnetoresistive element 10a. In this embodiment, the magnetoresistive element 10a and the magnetic anisotropy control unit 60 are stacked in the third direction (Z direction). Since the magnetic anisotropy control unit 60 is made of a conductive material, the measurement wiring 62 is provided so that a voltage from a measurement power supply is applied to the free magnetic layer 13 via the magnetic anisotropy control unit 60. Furthermore, since Figure 3 corresponds to the XZ cross-section of line A-A' in Figure 2, in Figure 3, the measurement wiring 62 is depicted as wiring connecting the Z1 end of the magnetoresistive element 10a to the ground terminal GND, and wiring connecting the Z2 end of the magnetic anisotropy control unit 60 to the output terminal V1.

[0034] In this embodiment, the magnetic anisotropy control unit 60 comprises a spin Hall portion 20 capable of generating spin orbit torque by energizing, and a magnetic switching portion 40 located between the spin Hall portion 20 and the free magnetic layer 13 and magnetically coupled with the free magnetic layer 13, and has a laminated structure in the Z direction (third direction).

[0035] The spin hole portion 20 generates a spin current in the thickness direction (Z direction) when current is passed in the in-plane direction (XY in-plane direction), and the generated spins are perpendicular to the direction of current flow in the plane. That is, the direction of current flow, the direction of spin current, and the direction of spin deflection (spin deflection direction) of spins flowing along the spin current are perpendicular to each other. Based on the spin-orbit torque (SOT) of the spin current generated in the spin hole portion 20, the magnetic anisotropy of the magnetic switching portion 40 is set in a predetermined direction, and the orientation of the magnetic anisotropy of the free magnetic layer 13 is set to align with the magnetic anisotropy of the magnetic switching portion 40 set in that predetermined direction.

[0036] The direction of magnetic anisotropy (setting direction) of the magnetic switching unit 40, which is set by the spin orbit torque, is determined by the direction of magnetic anisotropy (initial direction) in the non-energized state (a state in which no current is applied to the spin hole unit 20 and no measurement magnetic field H is applied to the free magnetic layer 13) and the direction of spin deflection (spin deflection direction) of the spins moving due to the spin current generated by the energization. When the measurement magnetic field H is in the X direction, the direction of the magnetic anisotropy that the free magnetic layer 13 should have, i.e., the direction of the bias magnetic field that the magnetic anisotropy control unit 60 should generate, is in the Y or Z direction, which is perpendicular to the X direction. The length (spin diffusion length) over which the spin current can be maintained aligned in a predetermined direction depends on the constituent material of the spin hole unit 20, but is always submicron or less. When the spin hole unit 20 is a film-like material, as in this embodiment, the energization direction is set in the XY plane direction such that the Z direction, which is its thickness direction, is the direction of the spin current. Therefore, the spin deflection direction is in the XY plane direction. Based on the above preconditions, the configuration of the magnetic anisotropy setting in the magnetic switching unit 40 can be divided into the following three types based on the combination of the initial direction and the spin deflection direction.

[0037] Type A: Initial direction: Z direction, Spin deflection direction: X direction, Setting direction: Y direction. Type B: Initial direction: Y direction, Spin deflection direction: Y direction, Setting direction: Y direction. Type C: Initial direction: Y direction, Spin deflection direction: X direction, Setting direction: Z direction.

[0038] In other words, in Type A, the magnetic anisotropy in the magnetic switching section 40 is set so that the spin deflection direction is perpendicular to the initial direction (orthoplane direction) and in the in-plane direction, and in this case, the set direction is perpendicular to both the initial direction and the spin deflection direction. In Type B, the magnetic anisotropy in the magnetic switching section 40 is set so that the initial direction (in-plane direction) and the spin deflection direction are collinear (same direction), and in this case, the set direction is also collinear to the initial direction. In Type C, the magnetic anisotropy in the magnetic switching section 40 is set so that the spin deflection direction is perpendicular to the initial direction (in-plane direction), and in this case, the set direction is perpendicular to both the initial direction and the spin deflection direction. Note that in Type C, it is also possible to swap the X direction and the Y direction, but when it is necessary to apply an effective bias magnetic field to the free magnetic layer 13 in a non-energized state, the initial direction is the Y direction as described above.

[0039] By applying current to the spin Hall portion 20 in the XY plane, the spin Hall effect and the Rashba-Edelstein effect are manifested, applying spin orbit torque to the magnetic switching portion 40. The materials constituting the spin Hall portion 20 include heavy metals (5d transition metals) with high specific gravity among paramagnetic transition metals such as Hf, Ta, W, Pt, and Ir; topological insulators such as BiSb, BiSe, Bi2Se3, and Bi2Te3; and Mn3X (X = Sn, Ge, Ga, RH, Pt, Ir), Mn 1-x Tr x Examples include antiferromagnetic materials such as the gamma phase (Tr = Ni, Fe, Cu, Ru, Pd, Ir, RH, Pd, Pt); and half-Heusler alloy topological semimetals made of mixed crystals of these materials, such as LuPtSb, LuPdBi, LuPtBi, ScPtBi, YAuPb, LaPtBi, CePtBi, THPtPb, and LaAuPb.

[0040] In one specific example shown in Figure 3, the spin hole portion 20 is a film-like body, which may be a single structure, i.e., composed of a single layer film, or a multilayer film. If it is a multilayer film, boundary regions may be formed between adjacent films. The spin hole portion 20 may be composed entirely of a single material, or of multiple materials. If it is composed of multiple materials, it may have a multilayer structure as described above, or it may have a dispersed structure. If it has a dispersed structure, the degree of dispersion is arbitrary, and it may be a structure in which nanocrystals are dispersed, or a certain pattern may be formed. Furthermore, a compositional distribution may be set in the spin hole portion 20.

[0041] The magnetic switching unit 40 can reversibly set its magnetic anisotropy to a predetermined direction based on the spin-orbit torque from the spin Hall unit 20. In this specification, this function of the magnetic switching unit 40 is referred to as the "magnetic anisotropy control function". Furthermore, "reversibly setting the magnetic anisotropy" means that, for the magnetic switching unit 40 whose magnetic anisotropy direction and degree have changed compared to before the start of supply of spin-orbit torque due to the start of supply of spin-orbit torque, when the supply of spin-orbit torque is stopped, the direction and degree of magnetic anisotropy of the magnetic switching unit 40 returns to the state before the supply of spin-orbit torque was started.

[0042] Since the magnetic switching section 40 is magnetically coupled to the free magnetic layer 13 of the magnetoresistive element 10a, a bias magnetic field is applied to the free magnetic layer 13 based on the spin-orbit torque from the spin Hall section 20. The magnetic switching section 40, like the spin Hall section 20, may be composed of a single material or multiple materials. If it is composed of multiple materials, it may have a dispersed structure or a compositional distribution may be set in the magnetic switching section 40.

[0043] The magnetic switching unit 40 may be made of any material as long as it appropriately has this magnetic anisotropy control function. Similar to the magnetization fixed layer 11, it may be composed of a ferromagnetic material or an antiferromagnetic material. Specific examples of the antiferromagnetic material include at least a part of the materials constituting the spin Hall unit 20. When the magnetic switching unit 40 contains an antiferromagnetic material, a magnetic field may be generated inside the magnetic switching unit 40 based on a physical phenomenon different from the magnetization in the case where the magnetic switching unit 40 contains a ferromagnetic material (for example, a virtual magnetic field). Therefore, in this specification, the concept of the term "magnetization" relating to the magnetic switching unit 40 and the like also includes the occurrence of a magnetic field inside the magnetic switching unit 40 based on such a physical phenomenon different from the magnetization of a ferromagnetic material.

[0044] In the present embodiment, a specific example is given in which the spin Hall unit 20 is made of an antiferromagnetic material, the magnetic switching unit 40 is made of a ferromagnetic material, and an exchange coupling interaction occurs between them.

[0045] In the individual magnetic field detection unit 100a according to the first example of the first embodiment shown in FIGS. 3 to 5, the setting mode of the magnetic anisotropy in the magnetic switching unit 40 is Type A. Therefore, the magnetic field 20af based on the exchange coupling interaction between the spin Hall unit 20 and the magnetic switching unit 40 is oriented in the Z direction, specifically in the Z1 direction in FIG. 3 and the like, so that the initial direction is oriented in the Z direction. As a result, the magnetization 40m of the magnetic switching unit 40 is also oriented in the Z1 direction, and further, the magnetization 13m of the free magnetic layer 13 magnetically coupled to the magnetic switching unit 40 is also oriented in the Z1 direction. That is, a bias magnetic field oriented in the Z1 direction, which is one of the directions orthogonal to the direction of the measurement magnetic field H (the first direction), is applied to the free magnetic layer 13. Therefore, in the present embodiment, the exchange coupling interaction between the spin Hall unit 20 and the magnetic switching unit 40 serves as a bias magnetic field source that causes the magnetic anisotropy of the free magnetic layer 13, which is the magnetosensitive unit, to follow a third direction (the Z direction in this example) different from the first direction when the magnetic anisotropy control unit 60 is in a non-energized state.

[0046] As described above, by applying the bias magnetic field in the direction orthogonal to the first direction, the resistance value of the magnetoresistive effect element 10a is maximized in a no-magnetic-field state where the measurement magnetic field H is not applied. In addition, when the application of the measurement magnetic field H is terminated and the state returns to the no-magnetic-field state, the magnetization 13m of the free magnetic layer 13 promptly becomes oriented in the Z1 direction along the bias magnetic field, and the resistance value of the magnetoresistive effect element 10a is maximized. Therefore, hysteresis in the measurement by the magnetoresistive effect element 10a is reduced, and measurement accuracy is improved.

[0047] Here, in the case where the bias magnetic field is applied in the direction orthogonal to the first direction, when the measurement magnetic field H is very small, the bias magnetic field exceeds the measurement magnetic field H and stops the rotation of the magnetic moment of the free magnetic layer 13, the magnetization 13m of the free magnetic layer 13 remains aligned in the Z1 direction. When the measurement magnetic field H exceeds the bias magnetic field and starts to rotate the magnetic moment of the free magnetic layer 13, the magnetization 13m of the free magnetic layer 13 has a component in the first direction, and the resistance value of the magnetoresistive effect element 10a starts to decrease. That is, the range of the dead magnetic field of the magnetosensitive portion composed of the free magnetic layer 13 can be changed by the strength of the bias magnetic field. In addition, when the strength of the bias magnetic field is increased to widen the range of the dead magnetic field of the magnetosensitive portion, the effective saturation magnetic flux density of the free magnetic layer 13 which is the magnetosensitive portion also increases.

[0048] Since the saturation magnetic flux density of the free magnetic layer 13 determines the upper limit of the measurement range of the magnetoresistive effect element 10a, the measurement range of the magnetoresistive effect element 10a can be controlled by adjusting the strength of the bias magnetic field. Specifically, when the strength of the bias magnetic field is low, even if the strength of the measurement magnetic field H is low, that is, even a weak magnetic field can be measured for its strength, but since the saturation magnetic flux density of the free magnetic layer 13 is also relatively low, it becomes difficult to measure the measurement magnetic field H having a strength higher than the saturation magnetic flux density. On the other hand, when the strength of the bias magnetic field is high, the strength of the measurement magnetic field H within the range of the dead magnetic field cannot be measured even if it is applied, but since the saturation magnetic flux density is relatively high, the high-strength measurement magnetic field H can be measured.

[0049] Here, if an electromagnet that energizes a coil is used as the bias magnetic field source, it is possible to change the strength of the bias magnetic field by the induced magnetic field that changes according to the amount of current applied. However, since the magnetic field created by the electromagnet spreads around the coil, the range over which it is affected tends to be wide. In contrast, when the magnetic anisotropy of a member that is magnetically coupled to the free magnetic layer 13 (magnetic switching unit 40 in this embodiment) is set using spin-start torque, the range over which the spin-orbit torque is affected is limited to the immediate vicinity, such as the member that is in contact with the member that generates the spin-orbit torque (spin hole unit 20 in this embodiment), thus narrowing the range over which the bias magnetic field is applied.

[0050] As shown in Figure 4, when a predetermined amount of control current 20c in the Y1 direction is applied to the spin Hall portion 20 in a first energized state, a spin current in the Z direction (spin deflection direction is the X direction) is generated, and the spin initiation torque based on the generated spin current extends to the magnetic switching portion 40, which is provided so as to be in contact with the spin Hall portion 20 in the Z direction. As shown in Figure 3, the magnetic switching portion 40 has magnetic anisotropy in the Z1 direction because the magnetization 40m is in the Z1 direction based on the exchange coupling interaction with the spin Hall portion 20. That is, since the initial direction is the Z direction, the setting of the magnetic anisotropy is Type A, and the magnetization 40m of the magnetic switching portion 40 is in the Y direction, or Y2 direction in Figure 4. This state is shown in Figure 2.

[0051] Even if the individual magnetic field detection units 100b and 100c are located in the vicinity of the individual magnetic field detection unit 100a (for example, within about 10 μm), the spin orbit torque from the spin Hall portion 20 will not reach the magnetic switching portion 40 of the individual magnetic field detection units 100b and 100c. Therefore, the free magnetic layer 13 of the individual magnetic field detection unit 100b and 100c will not be subjected to a bias magnetic field in the same direction as the free magnetic layer 13 of the individual magnetic field detection unit 100a.

[0052] Furthermore, since there is a positive correlation between the amount of control current 20c flowing through the spin Hall portion 20 and the magnitude of the spin orbit torque applied to the magnetic switching portion 40, the degree of magnetization 40m of the magnetic switching portion 40 can be changed by adjusting the amount of control current 20c flowing through the spin Hall portion 20, thereby controlling the strength of the bias magnetic field applied to the free magnetic layer 13. In other words, the magnetic anisotropy control unit 60 changes the degree of magnetic anisotropy (direction and strength of magnetization 13m) of the magnetosensitive portion (free magnetic layer 13) by controlling the energization.

[0053] Specifically, as shown in Figure 5, by creating a second energized state in which the amount of control current 20c flowing through the spin Hall portion 20 is increased compared to the state shown in Figure 4, the magnetization 40m in the Y2 direction in the magnetic switching portion 40 becomes stronger, and as a result, the magnetization 13m in the Y2 direction in the free magnetic layer 13 also becomes stronger. As a result, the effective saturation magnetic flux density of the free magnetic layer 13 becomes higher, making measurement possible even when the measured magnetic field H is of high intensity. Therefore, by adjusting the amount of control current 20c flowing through the spin Hall portion 20, it is possible to control the measurement range of the measured magnetic field H in the individual magnetic field detection portion 100a.

[0054] Furthermore, if the relationship between the amount of control current 20c flowing through the spin hole section 20 and the strength of the bias magnetic field acting on the free magnetic layer 13 is appropriately understood, it is possible to position the bias magnetic field in the same way as the magnetic field generated by the cancellation coil in the compensation coil method. Moreover, since the amount of control current 20c flowing through the spin hole section 20 controls the dead magnetic field of the free magnetic layer 13, it may be possible to measure the measured magnetic field H with high accuracy by modulating (strength, frequency) the amount of control current 20c flowing through the spin hole section 20 and performing signal processing (difference processing, Fourier transform processing, etc.) on the response from the individual magnetic field detection unit 100a or the response from the magnetic field detection unit 2.

[0055] (Second Example) Figure 6 is a diagram illustrating the non-energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 7 is a diagram illustrating the first energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 8 is a diagram illustrating the second energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figures 6 to 8 correspond to the XZ cross-sectional view along the line A-A' in Figure 2.

[0056] In the second example shown in Figures 6 to 8, the magnetic anisotropy setting in the magnetic switching section 40 is Type B. Therefore, the direction of the magnetization 13m of the free magnetic layer 13 in the non-energized state shown in Figure 6 and the direction of the magnetization 13m of the free magnetic layer 13 in the first energized state (a state in which a current in the X1 direction is applied to the spin Hall section 20) shown in Figure 7 are both in the Y2 direction. In other words, in this example, unlike the first example, the direction of the bias magnetic field applied to the free magnetic layer 13 can be kept constant between the non-energized state and the first energized state. In this case as well, the spin orbit torque generated by energizing the spin Hall portion 20 increases the degree of magnetization 40m (magnetic anisotropy) of the magnetic switching portion 40. By stopping the energization of the spin Hall portion 20, the degree of magnetization 40m (magnetic anisotropy) of the magnetic switching portion 40 returns to the state before the energization was started. Therefore, it can be said that the magnetic anisotropy of the magnetic switching portion 40 is reversibly set by energizing the spin Hall portion 20.

[0057] In this example, the configuration shown in Figure 2 is obtained because the direction of the bias magnetic field applied to the free magnetic layer 13 is the same in the Y2 direction in the non-energized state, the first energized state, and the second energized state. In this example, since the direction of the bias magnetic field applied to the free magnetic layer 13 is the same regardless of whether it is the first energized state or the second energized state, the continuity between the measurement of the measured magnetic field H in the non-energized state and the measurement of the measured magnetic field H in the first energized state and the second energized state is increased, and it is expected that the individual magnetic field detection unit 100a in this example will have higher measurement accuracy in the range of low intensity measured magnetic field H.

[0058] Furthermore, in this example, the direction of the bias magnetic field is constant (specifically, in the Y2 direction) in the non-energized state, the first energized state, and the second energized state, so measurement is possible in any state even if the measured magnetic field H is in the Z direction. In the first example, since the direction of the bias magnetic field in the non-energized state is in the Z direction, the measured magnetic field H in the Z direction can only be measured in the energized state.

[0059] (Third Example) Figure 9 is a diagram illustrating the non-energized state in the third example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 10 is a diagram illustrating the first energized state in the third example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figure 11 is a diagram illustrating the second energized state in the third example of the individual magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. Figures 9 to 11 correspond to the XZ cross-sectional view along the line A-A' in Figure 2.

[0060] In the third example shown in Figures 9 to 11, the magnetic anisotropy setting in the magnetic switching unit 40 is Type C. Therefore, as shown in Figures 10 and 11, the direction of the bias magnetic field applied to the free magnetic layer 13 in the energized state is the Z direction (Z1 direction in Figures 10 and 11). Since the Z direction is the thickness direction of the free magnetic layer 13, once magnetic anisotropy is set in this direction, the strength of the external magnetic field required to change the direction of magnetization 13m in the XY plane direction, which is perpendicular to this direction, is higher than the strength of the external magnetic field required to change the direction of magnetization 13m in other directions in the XY plane when the bias magnetic field is set in the XY plane direction. Therefore, the individual magnetic field detection unit 100a according to the third example tends to have a higher effective saturation magnetic flux density compared to the individual magnetic field detection unit 100a according to the other examples, and as a result, it is expected that a higher intensity measurement magnetic field H can be measured. In the third example, the non-energized state shown in Figure 9 corresponds to the configuration shown in Figure 2.

[0061] (Modifications) Modifications common to each example of the first embodiment will be described below. Figures 12A to 12C described below correspond to the XZ cross-sectional view along line A-A' in Figure 2. In the first to third examples described above, the magnetic anisotropy control unit 60 is composed of a spin Hall portion 20 and a magnetic switching portion 40, but is not limited to this. Other functional layers may be provided, or as shown in Figure 12A, the magnetic anisotropy control unit 60 may have a magnetic anisotropy spin Hall portion 601 in which the spin Hall portion 20 and the magnetic switching portion 40 are integrated. In the example of Figure 12A, the entire magnetic anisotropy control unit 60 is a magnetic anisotropy spin Hall portion 601. In this case, the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601) has magnetic anisotropy when it is not energized, and when the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601) is energized, a spin orbit torque is generated inside the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601), and as a result of this, a change (change in direction, change in degree) occurs in the magnetic anisotropy of the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601), and a bias magnetic field is generated that causes the magnetization 13m of the free magnetic layer 13 to align in a second direction different from the first direction which is the direction of the measured magnetic field H.

[0062] Figure 12A shows a configuration in which the spin Hall portion 20 and the magnetic switching portion 40 are integrated, with the first energized state of the third example as a specific example. Since the third example is Type C, the initial magnetic anisotropy of the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) is in the Y direction, and based on this, the magnetization of the magnetic anisotropy control unit 60, i.e., the initial magnetization 60mi, in the non-energed state where no control current 60c is applied to the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) is in the Y2 direction. The method for setting the direction of the initial magnetization 60mi is arbitrary, and it may be set by magnetic field deposition, in which the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) is deposited while applying an external magnetic field in the Y2 direction, or the initial magnetization 60mi may be in the Y direction by making the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) elongated in the Y direction and using shape magnetic anisotropy.

[0063] In the first to third examples described above, the magnetic switching unit 40 of the magnetic anisotropy control unit 60 is provided in contact with the free magnetic layer 13, but is not limited to this. The magnetic switching unit 40 and the free magnetic layer 13 only need to be magnetically coupled, and a layer having a magnetic material (e.g., a soft magnetic material) may be present between them. Alternatively, as shown in Figure 12B, the components constituting the magnetic anisotropy control unit 60, such as the magnetic switching unit 40, and the free magnetic layer 13 may be an integrated unit. In this case, the free magnetic layer 13 will have at least a part of the function of the magnetic anisotropy control unit 60.

[0064] In the example shown in Figure 12B, the integrated free magnetic layer 13 is shown as an integrated free magnetic layer 13A, which is a single integrated component (one piece) of the magnetic switching unit 40 and the free magnetic layer 13. Since Figure 12B also shows a structure in which the integrated free magnetic layer 13A is provided, using the first energized state of the third example as a specific example, the magnetic anisotropy setting of the integrated free magnetic layer 13A is Type C. Therefore, the direction of the magnetic field 60af based on the exchange coupling interaction between the magnetic anisotropy control unit 60 and the integrated free magnetic layer 13A is set to the Y2 direction, and the magnetization of the integrated free magnetic layer 13A, i.e., the initial magnetization 13mi, is set to the Y2 direction.

[0065] Furthermore, if the free magnetic layer 13 has the entire function of the magnetic anisotropy control unit 60, in other words, if the free magnetic layer 13, which is the magnetosensitive part, is an integral part of the magnetic anisotropy control unit 60, then it becomes possible to particularly reduce the number of components of the individual magnetic field detection unit 100a. In this case, the integrated free magnetic layer 13A also serves the function of the spin Hall part 20, so as shown in Figure 12C, a control current 13c is applied to the integrated free magnetic layer 13A in the direction of Y1 to generate a spin orbit torque, and the magnetic anisotropy (magnetization 13m) of the integrated free magnetic layer 13A is set in the direction of Z1.

[0066] (Second Embodiment) (First Example) Figure 13 is a diagram illustrating the non-energized state in a first example of the magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 14 is a diagram illustrating the first energized state in a first example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 15 is a diagram illustrating the second energized state in a first example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figures 13 to 15 correspond to the XZ cross-sectional view along the line A-A' in Figure 2.

[0067] The magnetic field detection unit 2 of the magnetic sensor 1 according to this embodiment includes a Hall element 10h as a magnetic detection element. The material constituting the Hall element 10h may be a known conductive material, a material that spontaneously generates magnetization inside, and an abnormal Hall effect may occur in the Hall element 10h.

[0068] As shown in Figure 13, in this embodiment, the magnetic field detection unit 2 is provided such that the magnetic anisotropy control unit 60 described in the first embodiment is magnetically coupled to the Hall element 10h. The configuration of the magnetic anisotropy control unit 60 is the same as that of the first example of the first embodiment shown in Figure 3, and the form of setting the magnetic anisotropy in the magnetic switching unit 40 is Type A. Therefore, in the non-energized state shown in Figure 13, the magnetization 10m of the Hall element 10h is in the Z direction (specifically, in the Z1 direction). Since this direction is perpendicular to the direction of the measurement magnetic field H (first direction, X direction), a bias magnetic field is applied to the Hall element 10h. Therefore, hysteresis is less likely to occur when the measurement magnetic field H in the first direction is applied, and the measurement accuracy of the magnetic field detection unit 2 is improved.

[0069] In the first example of the second embodiment, as shown in Figure 13, the supply wiring 63 for applying current from the power supply Vs of the power supply unit 3 to the Hall element 10h is configured so that current flows in the Z direction. The measurement wiring 62 connected to the measuring device Vm of the power supply unit 3 is configured to measure the voltage generated in the Y direction so that the Hall voltage generated in the Hall element 10h can be measured. It should be noted that measurement can be performed appropriately even if the power supply Vs and the measuring device Vm are swapped. In this case, the wiring of the supply wiring 63 and the measurement wiring 62 will remain the same, but their names will be swapped.

[0070] In the first energized state shown in Figure 14, the magnetic anisotropy setting in the magnetic switching section 40 is Type A, so a control current 20c is applied to the spin Hall section 20 in the Y direction (specifically, in the Y1 direction). The power supply unit 3 is equipped with a control power supply I for applying the control current 20c, and the control wiring 61 that applies the control current 20c from the control power supply I is shared with the measurement wiring 62 connected to the measurement device Vm, so that the measurement device Vm and the control power supply I are shared in the power supply unit 3. Specifically, the power supply unit 3 may be equipped with a control power supply I and a measurement device Vm, and either one may be connected to the wiring depending on the application, or the power supply unit 3 may be equipped with a device that has the functions of both a control power supply I and a measurement device Vm. The direction of spin deflection caused by energizing the spin Hall section 20 in the Y1 direction is the X direction, and the orbital torque of this spin causes the magnetization 10m of the Hall element 10h to be in the Y2 direction.

[0071] By adjusting the amount of control current 20c applied to the spin Hall portion 20 so that the strength of the magnetization 10m in the Y2 direction of the Hall element 10h generated in the first energized state is higher than the strength of the magnetization 10m when no current is applied to the spin Hall portion 20, the effective saturation magnetic flux density of the Hall element 10h in the first energized state becomes higher than the effective saturation magnetic flux density in the unenergetic state. As a result, the range of the measurable magnetic field H of the Hall element 10h in the first energized state is expanded beyond the range of the measurable magnetic field H when no current is applied to the spin Hall portion 20.

[0072] In the second energizing state, where the amount of control current 20c applied to the spin Hall portion 20 is increased compared to the first energizing state, as shown in Figure 15, the strength of the magnetization 10m in the Y2 direction of the Hall element 10h becomes stronger than the magnetization 10m in the first energizing state. As a result, the effective saturation magnetic flux density of the Hall element 10h in the second energizing state becomes higher than the effective saturation magnetic flux density in the first energizing state. Consequently, the range of the measurable magnetic field H of the Hall element 10h in the second energizing state is wider than the range of the measurable magnetic field H in the first energizing state.

[0073] (Second Example) Figure 16 is a diagram illustrating the non-energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 17 is a diagram illustrating the first energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 18 is a diagram illustrating the second energized state in a second example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 19 is a diagram illustrating a modified example (second energized state) of the second example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figures 16 to 19 correspond to the XZ cross-sectional view along the line A-A' in Figure 2.

[0074] The magnetic field detection unit 2 in the magnetic sensor 1 according to the second example of the second embodiment differs from the magnetic field detection unit 2 according to the first example of the second embodiment in that the magnetic anisotropy setting in the magnetic switching unit 40 is Type B. Therefore, in the non-energized state shown in Figure 16, the magnetization 10m of the Hall element 10h is in the Y2 direction based on the magnetic field 20af in the Y2 direction, which is based on the exchange coupling interaction between the spin Hall unit 20 and the magnetic switching unit 40. Since this direction is perpendicular to the direction of the measured magnetic field H (first direction, X direction), a bias magnetic field is applied to the Hall element 10h. Therefore, hysteresis is less likely to occur when the measured magnetic field H in the first direction is applied, and the measurement accuracy of the magnetic field detection unit 2 is improved. In the specific example shown in Figure 16, the supply wiring 63 for applying current from the power supply Vs provided by the power supply unit 3 to the Hall element 10h is provided so that the current flows in the Z direction. Furthermore, the measurement wiring 62 connected to the measuring device Vm, which measures the Hall voltage generated in the Hall element 10h, is provided to measure the voltage generated in the Y direction.

[0075] In the first energized state shown in Figure 17, the magnetic anisotropy setting in the magnetic switching section 40 is Type B, so a control current 20c is applied to the spin Hall section 20 in the X direction (specifically, in the X1 direction) from the control power supply I provided in the power supply unit 3. Unlike the first example of the second embodiment, the control wiring 61 that applies the control current 20c from the control power supply I is provided separately from the measurement wiring 62 connected to the measurement device Vm provided in the power supply unit 3. The direction of spin deflection caused by energizing the spin Hall section 20 in the X1 direction is the Y direction, and the orbital torque of this spin causes the magnetization 10m of the Hall element 10h to be in the Y2 direction.

[0076] The amount of control current 20c applied to the spin Hall portion 20 is adjusted so that the strength of the magnetization 10m in the Y2 direction of the Hall element 10h generated in the first energized state is higher than the strength of the magnetization 10m when no current is applied to the spin Hall portion 20. As a result, the effective saturation magnetic flux density of the Hall element 10h in the first energized state is higher than the effective saturation magnetic flux density in the de-energized state. Consequently, the range of the measurable magnetic field H of the Hall element 10h in the first energized state is expanded beyond the range of the measurable magnetic field H when no current is applied to the spin Hall portion 20.

[0077] In the second energizing state, where the amount of control current 20c applied to the spin Hall portion 20 is increased compared to the first energizing state, the magnetization strength 10m in the Y2 direction of the Hall element 10h becomes stronger than the magnetization 10m in the first energizing state, as shown in Figure 18. As a result, the effective saturation magnetic flux density of the Hall element 10h in the second energizing state becomes higher than the effective saturation magnetic flux density in the first energizing state, and consequently, the range of the measurable magnetic field H of the Hall element 10h in the second energizing state becomes wider than the range of the measurable magnetic field H in the first energizing state.

[0078] In the second example of the second embodiment, the magnetic anisotropy setting in the magnetic switching unit 40 is Type B, so the direction of the bias magnetic field applied to the Hall element 10h is the same in the non-energized state and the first energized state. Therefore, the measurement accuracy may be improved in the range of low measured magnetic field H. Furthermore, it is possible to configure the system to measure measured magnetic field H in directions different from those shown in Figures 16 to 18. Specifically, as shown in Figure 19, even when the measured magnetic field H is in the Z direction, by setting the direction of application of the control current 20c from the control power supply I to the X direction, the Hall voltage generated in the Y direction can be measured by the measuring device Vm. In this case, as shown in Figure 19, it is possible to share the supply power supply Vs and the control power supply I, and to share the control wiring 61 and the supply wiring 63.

[0079] (Third Example) Figure 20 is a diagram illustrating the non-energized state in a third example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 21 is a diagram illustrating the first energized state in a third example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figure 22 is a diagram illustrating the second energized state in a third example of the individual magnetic field detection unit of the magnetic sensor according to the second embodiment of the present invention. Figures 20 to 22 correspond to the XZ cross-sectional view along the line A-A' in Figure 2.

[0080] The magnetic field detection unit 2 of the magnetic sensor 1 according to the third example of the second embodiment differs from the magnetic field detection unit 2 according to the first example of the second embodiment in that the magnetic anisotropy setting in the magnetic switching unit 40 is Type C. In the non-energized state shown in Figure 20, the magnetization 10m of the Hall element 10h is in the Y2 direction based on the magnetic field 20af in the Y2 direction, which is based on the exchange coupling interaction between the spin Hall unit 20 and the magnetic switching unit 40. Since this direction is perpendicular to the direction of the measurement magnetic field H (first direction, X direction), a bias magnetic field is applied to the Hall element 10h. Therefore, hysteresis is less likely to occur when the measurement magnetic field H in the first direction is applied, and the measurement accuracy of the magnetic field detection unit 2 is improved. In the specific example shown in Figure 20, the supply wiring 63 for applying current from the power supply Vs of the power supply unit 3 to the Hall element 10h is provided so that the current flows in the Z direction. Furthermore, the measurement wiring 62 connected to the measuring device Vm of the power supply unit 3 is provided to measure the voltage generated in the Y direction so that the Hall voltage generated in the Hall element 10h can be measured.

[0081] In the first energized state shown in Figure 21, the magnetic anisotropy setting in the magnetic switching unit 40 is Type C, so a control current 20c is applied to the spin Hall unit 20 in the Y direction (specifically, in the Y1 direction) from the control power supply I provided in the power supply unit 3. The control power supply I is shared with the measuring device Vm, as in the first example of the second embodiment, and as a result, the control wiring 61 and the measuring wiring 62 are shared. The direction of the spin generated by energizing the spin Hall unit 20 in the Y1 direction is the X direction, and the orbital torque of this spin causes the magnetization 10m of the Hall element 10h to be in the Z1 direction.

[0082] The amount of control current 20c applied to the spin Hall portion 20 is adjusted so that the strength of the magnetization 10m in the Z1 direction of the Hall element 10h generated in the first energized state is higher than the strength of the magnetization 10m when no current is applied to the spin Hall portion 20. As a result, the effective saturation magnetic flux density of the Hall element 10h in the first energized state is higher than the effective saturation magnetic flux density in the de-energized state. Consequently, the range of the measurable magnetic field H of the Hall element 10h in the first energized state is expanded beyond the range of the measurable magnetic field H when no current is applied to the spin Hall portion 20.

[0083] In the second energizing state, where the amount of current applied to the spin Hall portion 20 is increased compared to the first energizing state, the magnetization strength 10m in the Y2 direction of the Hall element 10h becomes stronger than the magnetization strength 10m in the first energizing state, as shown in Figure 22. As a result, the effective saturation magnetic flux density of the Hall element 10h in the second energizing state becomes higher than the effective saturation magnetic flux density in the first energizing state, and consequently, the range of the measurable magnetic field H of the Hall element 10h in the second energizing state becomes wider than the range of the measurable magnetic field H in the first energizing state.

[0084] (Modifications) Modifications common to each example of the second embodiment will be described below. Figures 23A to 23C described below correspond to the XZ cross-sectional view along line A-A' in Figure 2. In the first to third examples of the second embodiment described above, the magnetic anisotropy control unit 60 is composed of a spin Hall portion 20 and a magnetic switching portion 40, but is not limited thereto. Other functional layers may be provided, or as shown in Figure 23A, the magnetic anisotropy control unit 60 may have a magnetic anisotropy spin Hall portion 601 in which the spin Hall portion 20 and the magnetic switching portion 40 are integrated. In the first modification shown in Figure 23A, the entire magnetic anisotropy control unit 60 is a magnetic anisotropy spin Hall portion 601. In this case, the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601) has magnetic anisotropy when de-energized, and when energy is applied to the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601), a spin orbit torque is generated inside the magnetic anisotropy control unit 60, and as a result of this, a change (change in direction, change in degree) occurs in the magnetic anisotropy of the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall section 601), and a bias magnetic field is generated that causes the magnetization 10m of the Hall element 10h to align in a second direction different from the first direction, which is the direction of the measured magnetic field H.

[0085] Figure 23A shows a configuration in which the spin Hall portion 20 and the magnetic switching portion 40 are integrated, with the second energized state of the third example of the second embodiment as a specific example. Since the third example of the second embodiment is Type C, the initial magnetic anisotropy of the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) is in the Y direction. Based on this, in the non-energed state where no control current 20c is applied to the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601), the magnetization of the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601), i.e., the initial magnetization 60mi, is in the Y2 direction. The method for setting the orientation of the initial magnetization 60mi is arbitrary. It may be set by magnetic field deposition, where the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) is deposited while applying an external magnetic field in the Y2 direction. Alternatively, the magnetic anisotropy control unit 60 (magnetic anisotropy spin Hall portion 601) may be made elongated in the Y direction, and the initial magnetization 60mi may be set in the Y direction by shape magnetic anisotropy.

[0086] In the first to third examples of the second embodiment described above, the magnetic switching unit 40 of the magnetic anisotropy control unit 60 is provided to be in contact with the Hall element 10h, but is not limited to this. The magnetic switching unit 40 and the Hall element 10h only need to be magnetically coupled, and a layer having a magnetic material (for example, a soft magnetic material) may be present between them. Alternatively, as shown in Figure 23B, the components constituting the magnetic anisotropy control unit 60, such as the magnetic switching unit 40, and the Hall element 10h may be integrated.

[0087] In this case, the Hall element 10h has at least a part of the function of the magnetic anisotropy control unit 60. In the second modified example of the second embodiment shown in Figure 23B, a member in which the magnetic switching unit 40 and the Hall element 10h are integrated is shown as an integrated Hall element 10hA. Since Figure 23B also shows a structure in which an integrated Hall element 10hA is provided with the second energized state of the third example of the second embodiment as a specific example, the magnetic anisotropy setting of the integrated Hall element 10hA is Type C. Therefore, the direction of the magnetic field 60af based on the exchange coupling interaction that occurs between the magnetic anisotropy control unit 60 and the integrated Hall element 10hA is set to the Y2 direction, and the magnetization of the integrated Hall element 10hA, i.e., the initial magnetization 10mi, is set to the Y2 direction.

[0088] Furthermore, if the Hall element 10h has the entire function of the magnetic anisotropy control unit 60, in other words, if the Hall element 10h, which is the magnetosensitive part, is an integral part of the magnetic anisotropy control unit 60, then it becomes possible to particularly reduce the number of components of the individual magnetic field detection unit 100a. In this case, the integrated Hall element 10hA also serves the function of the spin Hall part 20, so as shown in Figure 23C, current is applied to the integrated Hall element 10hA in the direction of Y1 to generate a spin orbit torque, and the magnetic anisotropy (magnetization 10m) of the integrated Hall element 10hA is set in the direction of Z1.

[0089] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0090] This disclosure includes the following embodiments: (1) A magnetic sensor comprising a magnetic sensing element having a magnetic sensing portion and a magnetic anisotropy control unit capable of controlling the direction and / or degree of magnetic anisotropy of the magnetic sensing portion by energizing, wherein the magnetic anisotropy control unit makes the range of the saturation magnetic flux density and / or the dead magnetic field of the magnetic sensing portion variable by continuously changing the strength of the bias magnetic field applied to the magnetic sensing portion according to the amount of energized current. (2) The magnetic sensor according to (1) above, wherein the magnetic anisotropy control unit can set the direction of the magnetic anisotropy of the magnetic sensing portion to a direction different from a first direction which is the sensitivity axis of the magnetic sensing portion. (3) The magnetic sensor according to (1) above, wherein the magnetic anisotropy control unit aligns the magnetic anisotropy of the magnetic sensing portion in a predetermined direction when no energized current is applied, and changes the direction and / or degree of magnetic anisotropy of the magnetic sensing portion according to the amount of energized current when energized. [4] The magnetic sensor according to [1] above, characterized in that at least two of the following are mutually orthogonal: the initial direction of magnetic anisotropy in the magnetic sensing portion, the spin deflection direction generated when current is supplied to the magnetic anisotropy control unit, and the direction of magnetic anisotropy in the magnetic sensing portion when current is supplied to the magnetic anisotropy control unit. [5] The magnetic sensor according to [1] above, characterized in that the magnetic anisotropy control unit controls the direction and / or degree of magnetic anisotropy in the magnetic sensing portion based on the spin orbit torque generated by the supply of current. [6] The magnetic sensor according to [1] above, characterized in that the magnetic anisotropy control unit has a spin Hall portion capable of generating spin orbit torque in response to the supply of current, and a magnetic switching portion that is magnetically coupled to the magnetic sensing portion. [7] The magnetic sensor according to [6] above, characterized in that the magnetic anisotropy control unit has a structure in which the spin Hall portion and the magnetic switching portion are integrated, and the direction and / or degree of magnetic anisotropy in the magnetic sensing portion is controlled by supplying current to the integrated structure. [8] The magnetic sensor according to [1], further comprising a bias magnetic field source that causes the magnetic anisotropy of the magnetosensitive portion to align in a predetermined direction when the magnetic anisotropy control unit is not energized. [9] The magnetic sensor according to [8], further comprising a portion made of an antiferromagnetic material, wherein the exchange coupling interaction between the antiferromagnetic portion and the magnetic material serves as the bias magnetic field source.

[10] The magnetic sensor according to [6] above, wherein the magnetic switching unit is integral with the magnetosensitive unit.

[11] The magnetic sensor according to [1] above, wherein the magnetosensitive unit is integral with the magnetic anisotropy control unit.

[12] The magnetic sensor according to [1] above, characterized in that the magnetic sensing element is a magnetoresistive element including a magnetized fixed layer, a non-magnetic layer, and a free magnetic layer.

[13] The magnetic sensor according to [1] above, characterized in that the magnetic sensing element is a Hall element.

[14] The magnetic sensor according to [9] above, wherein the magnetic anisotropy control unit includes a portion made of the antiferromagnetic material.

[0091] The present invention is useful as a magnetic sensor with a wide measurement range (dynamic range) of the measured magnetic field H.

[0092] 1: Magnetic sensor 2: Magnetic field detection unit 3: Power supply unit 4: Magnetic field calculation unit 5: Amplifier 6: A / D conversion circuit 7: Control unit 10P: Detection center 10a, 10b, 10c, 10d: Magnetoresistive element 10h: Hall element 10hA: Integrated Hall element 10m, 11m, 13m, 40m: Magnetization 10mi, 13mi, 60mi: Initial magnetization 11: Magnetization fixed layer 12: Non-magnetic layer 13: Free magnetic layer 13A: Integrated free magnetic layer 15: Full bridge circuit 20: Spin Hall section 20af, 60af: Magnetic field based on exchange coupling interaction 40: Magnetic switching section 60: Magnetic anisotropy control unit 601: Magnetic anisotropy spin Hall section 61: Control wiring 62 : Measurement wiring 63 : Supply wiring 100a, 100b, 100c, 100d : Individual magnetic field detection unit 13c, 20c, 60c : Control current GND : Ground terminal H : Measured magnetic field I : Control power supply V1, V2 : Output terminal Vdd : Power supply terminal Vm : Measurement device Vs : Power supply

Claims

1. A magnetic sensor comprising: a magnetic sensing element having a magnetic sensing portion whose sensitivity axis is aligned with a first direction; and a magnetic anisotropy control unit that reversibly changes the measurement sensitivity of the magnetic sensing portion, wherein the magnetic anisotropy control unit aligns the magnetic anisotropy of the magnetic sensing portion with a second direction different from the first direction based on the spin orbit torque generated by energization.

2. The magnetic sensor according to claim 1, wherein the magnetic anisotropy control unit changes the degree of magnetic anisotropy of the magnetic sensing part by controlling the energization.

3. The magnetic sensor according to claim 2, wherein the magnetic anisotropy control unit comprises: a spin Hall portion capable of generating the spin orbit torque in response to current; and a magnetic switching portion that is magnetically coupled with the magnetosensitive portion and whose magnetic anisotropy is reversibly aligned in the second direction based on the spin orbit torque generated by the spin Hall portion.

4. The magnetic switching unit is an integral part of the magnetic sensing unit, as described in claim 3.

5. The magnetic sensor according to claim 2, wherein the magnetic anisotropy control unit is magnetically coupled to the magnetosensitive unit and capable of generating the spin-orbit torque in response to current, and has a magnetic anisotropy spin Hall portion in which the magnetic anisotropy is reversibly aligned in the second direction based on the generated spin-orbit torque.

6. The magnetic sensor according to claim 2, wherein the magnetic sensing unit is an integral part of the magnetic anisotropy control unit.

7. The magnetic sensor according to claim 1, further comprising a bias magnetic field source that causes the magnetic anisotropy of the magnetosensitive portion to align with a third direction different from the first direction when the magnetic anisotropy control unit is not energized.

8. The magnetic sensor according to claim 7, wherein the third direction is along the second direction.

9. The magnetic sensor according to claim 7, wherein the first direction, the second direction, and the third direction are mutually orthogonal.

10. The magnetic sensor according to claim 7, further comprising a portion made of an antiferromagnetic material, wherein the exchange coupling interaction between the antiferromagnetic material portion and the magnetic material serves as the bias magnetic field source.

11. The magnetic sensor according to claim 10, wherein the magnetic anisotropy control unit includes a portion made of the antiferromagnetic material.

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