Magnetoresistive element for detecting magnetic fields along the Z axis

Abstract

A magnetoresistive element is provided that can measure an external magnetic field along an out-of-plane axis that is substantially perpendicular to the plane of the sensing layer. The magnetoresistive element (2) includes a reference layer (210) having a fixed reference magnetization, a sensing layer (23) having a free sense magnetization (230), and a tunnel barrier layer (22) between the reference layer (21) and the sensing layer (23), the magnetoresistive element (2) being configured to measure an external magnetic field (60) oriented substantially perpendicular to the plane of the two layers (21, 23). The reference magnetization (210) is oriented substantially perpendicular to the plane of the reference layer (21). The sense magnetization (230) has a vortex configuration (60) in the absence of an external magnetic field, with the vortex core (231) being substantially parallel to the plane of the sensing layer (23) and having a magnetization along an out-of-plane axis (50) substantially perpendicular to the plane of the sensing layer (23).

Description

[Technical Field]

[0001] The present invention relates to a magnetoresistive element (magnetoresistive effect element) having a sensing layer, which measures an external magnetic field along an axis substantially perpendicular to the plane of the sensing layer. The present invention further relates to a method for operating the magnetoresistive element. [Background technology]

[0002] Currently, magnetic sensors are widely used as electronic compasses in mobile devices such as mobile phones. For a two-dimensional magnetic field in the XY plane, the X and Y components of the magnetic field can be measured using two orthogonal sensors. However, measuring the magnetic field in the Z-axis direction presents many difficulties. Typically, the following solutions are used.

[0003] One solution involves a separate single-axis planar magnetoresistive sensor mounted perpendicularly to a two-axis planar sensor. This solution requires assembling two different sensors: a two-axis magnetoresistive sensor for the XY axes and a magnetoresistive sensor for the Z axis.

[0004] Another solution involves a flux guide that converts the magnetic field in the Z-axis direction into magnetic field components in the X-axis and Y-axis directions. For example, Patent Document 1 discloses a single-chip 3-axis AMR sensor that implements measurement of the magnetic field in the Z-axis direction by placing a flux guide on top of an in-plane sensor. In such a solution, the magnetic field in the Z-axis direction is not fully converted to the X-axis and Y-axis directions. Furthermore, such a sensor design requires the use of a specific algorithm to calculate the magnetic field in the Z-axis direction, making the sensor design more complex.

[0005] Another solution involves microfabricating a substrate to form an inclined surface and depositing sensors that partially detect magnetic fields in the Z-axis direction onto it. Such a process is very complex, has low spatial efficiency, and may cause some shadowing effect on the sensor deposition, which could degrade the sensor's performance.

[0006] Another solution involves using a magnetic material with perpendicular magnetic anisotropy to measure the magnetic field in the Z-axis direction. For example, Patent Document 2 discloses a magnetic sensor that measures the Z-axis component of an external magnetic field using a perpendicular magnetic anisotropy material. Perpendicular magnetic anisotropy materials have high coercivity and low magnetoresistance. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2012 / 206137 [Patent Document 2] U.S. Patent Application Publication No. 2013 / 168787 [Overview of the Initiative]

[0008] This disclosure relates to a magnetoresistive element comprising a reference layer having a fixed reference magnetization, a sensing layer having a free sensing magnetization, and a tunnel barrier layer between the reference layer and the sensing layer. The magnetoresistive element is configured to measure an external magnetic field oriented substantially perpendicular to the plane of each layer. The reference magnetization is oriented substantially perpendicular to the plane of the reference layer. This sensing magnetization has a vortex configuration in the absence of an external magnetic field. The vortex configuration has a magnetization direction of vortex cores along an out-of-plane axis substantially parallel to the plane of the sensing layer and substantially perpendicular to the plane of the sensing layer. From one perspective, the detection layer has a thickness greater than 60 nm, and here, the detection layer comprises a first soft ferromagnetic material having a detection magnetization of 230 between 300 and 600 kA / m.

[0009] This disclosure further relates to a method for manipulating a magnetoresistive element, the method being: The direction of the vortex core is selected by applying an initial magnetic field until it reaches the vortex emission magnetic field, Reducing the initialization magnetic field to a level below the nucleation magnetic field in which the vortex is reformed (here, the magnetization direction of the vortex core is determined by the polarity of the vortex emission magnetic field and the nucleation magnetic field), Measuring the external magnetic field and It is equipped with.

[0010] The magnetoresistive element disclosed herein can measure an external magnetic field along an out-of-plane axis substantially perpendicular to the plane of the sensing layer. The vortex configuration of the magnetoresistive element may have an emission magnetic field exceeding 200 mT or 250 mT.

[0011] The magnetoresistive element has low hysteresis, less than 300 pV / V from the magnitude of the external magnetic field to the emission magnetic field, high linearity, and an error of less than 2% or 1%.

[0012] Exemplary embodiments of the present invention are disclosed within the description of the specification and depicted by the drawings.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 represents a magnetoresistive element according to one embodiment. [Figure 2] FIG. 2 shows the magnetization curve of the magnetoresistive element. [Figure 3] FIG. 3 shows an enlarged view of a part of the reversible linear portion of the magnetization curve of FIG. 2. [Figure 4] FIG. 4 reports the magnetization curves for multiple values of the thickness of the sensing layer and the magnetization curve of a magnetoresistive element with a lateral dimension of 250 nm. [Figure 5] FIG. 5 reports the magnetization curves for multiple values of the thickness of the sensing layer and the magnetization curve of a magnetoresistive element with a lateral dimension of 450 nm. [Figure 6] FIG. 6 reports the sensitivity of the magnetoresistive element as a function of the thickness of the sensing layer. [Figure 7] FIG. 7 shows the magnetization curve of a magnetoresistive element with a lateral dimension of 250 nm, a thickness of 110 nm, and a magnetic moment of 600 kA / m. [Figure 8] FIG. 8 shows the magnetization curve of a magnetoresistive element with a lateral dimension of 250 nm, a sensing layer thickness of 46 nm, and a magnetic moment of 400 kA / m. [Figure 9] FIG. 9 shows the reference layer of a magnetoresistive element according to one embodiment. [Figure 10] FIG. 10 shows a magnetoresistive element including first and second sensing layers according to one embodiment. [Figure 11] Figure 11 shows a second detection layer comprising multiple second ferromagnetic sublayers according to one embodiment. [Figure 12] Figure 12 shows a second detection layer comprising a plurality of second ferromagnetic sublayers and a second insertion sublayer according to one embodiment. [Figure 13] Figure 13 shows a magnetoresistive element comprising first and second sensing layers according to another embodiment. [Figure 14] Figure 14 shows a first detection layer comprising a plurality of first ferromagnetic sublayers according to one embodiment. [Modes for carrying out the invention]

[0014] Figure 1 shows a magnetoresistive element 2 according to one embodiment. The magnetoresistive element comprises a reference layer 21 having a fixed reference magnetization 210, a sensing layer 23 having a free sensing magnetization 230, and a tunnel barrier layer 22 between the reference layer 21 and the sensing layer 23. The sensing magnetization 230 has a vortex configuration substantially parallel to the plane of the sensing layer 23 in the absence of an external magnetic field 60. The reference layer 21 may have perpendicular magnetic anisotropy (PMA) such that the reference magnetization 210 is oriented substantially perpendicular to the plane of the reference layer 21.

[0015] The magnetoresistive element 2 can measure an external magnetic field 60 that is oriented substantially perpendicular to the planes of the reference layer and the sensing layers 21 and 23.

[0016] The sensing layer 23 has a sensing magnetization 230 directional distribution with a vortex configuration. As a result, the vortex magnetization curves in a circular path around the vortex core 231 along the edge of the sensing layer 23. The vortex magnetization direction may be oriented clockwise or counterclockwise. During normal sensor operation, the magnetization of the vortex core 231 may change in a direction substantially perpendicular to the plane of the sensing layer 23 (or in the ±z direction) in response to the external magnetic field 60. Referring to Figure 1, the magnetization of the vortex core 231 can be oriented upward (i.e., towards the +z direction) or downward (i.e., towards the opposite -z direction). The size of the vortex core increases or decreases in the +z direction or -z direction as the magnitude of the external magnetic field 60 increases or decreases. However, during normal sensor operation, the vortex core magnetization direction ±z, or the vortex core magnetization polarity, is fixed.

[0017] Due to the practical size of the magnetoresistive element 2 and the thickness of the sensing layer 23, this vortex configuration provides linear and non-hysteresis behavior within a range of large and large external magnetic fields 60. The linear and non-hysteresis portions of the magnetization curve facilitate the measurement of small fluctuations in the external magnetic field 60. Thus, the vortex configuration is advantageous for multiple applications of the magnetic sensor.

[0018] Figure 2 shows (symbol B extz The magnetization curve (or hysteresis response) of the magnetoresistive element 2 as a function of the external magnetic field 60 (shown as shown) is shown. Here, "mz" is the average component ± z along the direction of the detected magnetization. <mz>(or normalized to the z component of the detected magnetization Ms) (mz = <mz>corresponds to ( / Ms). In the case of the vortex configuration, the magnetization curve is up to the point where the vortex emission magnetic field is reached at the H expl point, characterized by a linear increase in the vortex core magnetization by the external magnetic field B extz . At this point, the detected magnetization 230 magnetically saturates (represented by the upward arrow (direction +z)). The vortex state in the detection layer 23 recovers when the external magnetic field B extz decreases below the nucleation magnetic field H nucl . The detected magnetization 230 magnetically saturates (represented by the downward arrow (direction -z)) when the external magnetic field B expl decreases until it reaches the vortex emission magnetic field at the H extz point (negative external magnetic field B ext ). The nucleation magnetic field H nucl is the field where the vortex reforms after the vortex emission. As long as the magnitude of the external magnetic field B extz is below the absolute value corresponding to the expulsion magnetic field (+ / -H expl ), the magnetization curve includes a reversible linear portion corresponding to the change in the magnetization of the vortex core 231 by the external magnetic field 60. The vortex core magnetization polarity can be reversed when exceeding the emission magnetic field H expl (between the directions z and -z).

[0019] FIG. 3 shows an enlarged view of a part of the reversible linear portion of the magnetization curve of FIG. 2. When the external magnetic field B extz increases from the nucleation magnetic field H nucl , compared with when the external magnetic field B extz decreases from the nucleation magnetic field H nucl , the magnetization curve shifts to a higher magnetization value as the external magnetic field B extz increases. That is, the reversible linear portion of the magnetization curve shows hysteresis due to the difference in the vortex core magnetization polarity, that is, the magnetization direction of the vortex core 231.

[0020] The vortex core magnetization polarity depends on the nucleation magnetic field + / -H nucl where the vortex reforms after the vortex emission. Next, only one of the branches of the magnetization curve can be used to operate the magnetoresistive element 2. The branch is, for example, branch A (see FIG. 3) when the magnetic field is swept from the positive nucleation magnetic field +H nucl (and the positive vortex emission magnetic field +H expl ) and returns negatively, or when the magnetic field is swept from the negative nucleation magnetic field -H nucl (and negative eddy emission magnetic field -H expl This is branch B when the crosshairs are swept back to positive.

[0021] The operation method for the magnetoresistive element 2 is to apply an initial magnetic field to the magnetoresistive element 2 and then generate an eddy emission magnetic field H expl Select the direction of magnetization of the vortex core, z or -z (vortex core magnetization polarity), until it reaches a certain point, and then the nucleation magnetic field H where the vortex reforms. nucl Further down, a step to reduce the initial magnetic field may be included. The vortex core magnetization polarity is determined by the vortex emission magnetic field H expl and nucleation field H nucl This is determined by the polarity. This method further includes the step of measuring the external magnetic field 60.

[0022] After applying an initial magnetic field, this method may further include a step of programming the magnetoresistive element 2 to program the orientation of the reference magnetization 210. The programming step can be performed by applying a programming magnetic field adapted to orient the reference magnetization 210. The programming step may further include heating the magnetoresistive element 2 to a temperature that facilitates the orientation of the reference magnetization 210, for example, a temperature at which the reference magnetization 210 is released. Heating of the magnetoresistive element 2 can be done using resistance heating or laser heating. During the programming step, the vortex core magnetization polarity can be considered fixed.

[0023] It should be noted that the operation of the magnetoresistive element 2 is not limited to any specific part of branch A or B shown in Figure 3. In fact, the magnetoresistive element 2 can be operated at any point within the linear region of branch A or branch B (the latter having the eddy magnetization polarity reversed compared to branch A).

[0024] In any case, the magnetoresistive element 2 emits an eddy field of + / -H expl It is necessary to measure an external magnetic field of 60 lower than this. The eddy magnetization polarity is fixed during sensor operation and is independent of the vortex's chirality (clockwise or counterclockwise direction).

[0025] Observation of the vortex structure in the detection layer 23 depends on numerous factors, including the material properties of the detection layer 23. Generally, the vortex structure is preferred at zero applied magnetic field by increasing the aspect ratio of the thickness to the diameter of the detection layer 23. The aspect ratio is usually much smaller than 1 (e.g., 0.01 to 0.5). Also, the values ​​and slopes of the linear portion of the magnetization curve in Figure 2 are strongly dependent on the size of the detection layer 23.

[0026] In particular, the vortex configuration is characterized by its magnetic susceptibility χ, which corresponds to the slope of the linear region of the magnetization curve.

number

[0027] The sensitivity S of the magnetoresistive element 2 is proportional to the product of the magnetic susceptibility χ and the tunnel magnetoresistance (TMR) of the magnetoresistive sensor element 2.

number

[0028] Figure 4 shows the z-orientation external magnetic field B related to the magnetization of the detection layer 23. extz The magnetization curves for a given TMR value are reported for several thicknesses of the sensing layer 23, namely between 10 nm and 60 nm. The magnetoresistive element 2 has a lateral dimension D of approximately 250 nm. Figure 4 shows the slope of the magnetization curve, and consequently the increase in magnetic susceptibility χ, with increasing thickness of the sensing layer 23. For a given TMR value, increasing the thickness of the sensing layer 23 results in an increase in the sensitivity S of the magnetoresistive element 2. This is in contrast to the case where the sensing layer 23 has a vortex configuration within its plane and a vortex core magnetization that is reversibly movable substantially parallel to the plane of the sensing layer 23.

[0029] Figure 5 shows the external magnetic field B positioned z-axis for multiple thicknesses of the sensing layer 23 (i.e., various thicknesses of the sensing layer 23 between 10 nm and 60 nm). extz The magnetization curve for the magnetoresistive element 2 is reported. The magnetoresistive element 2 has a lateral dimension of approximately 450 nm. Figures 4 and 5 show that as the magnetic susceptibility χ increases, the sensitivity S of the magnetoresistive element 2 increases for a given TMR value, and the lateral dimension D of the magnetoresistive element 2 decreases. For layers 21 and 23 of a given thickness, the value of sensitivity S increases as the aspect ratio t / D of the thickness t to the diameter (lateral dimension) D of the magnetoresistive element 2 increases.

[0030] The sensitivity S of the magnetoresistive element 2 is shown in Figure 6 as a function of the thickness of the sensing layer 23. Simulation tests were conducted for the lateral dimension D of the magnetoresistive element 2 to be 150 nm, 200 nm, and 250 nm, and for the magnetization of the sensing layer 23 to be 400 and 600 kA / m. The TMR value of the magnetoresistive element 2 was assumed to be 100%. Figure 6 shows that a higher sensitivity S value is obtained when the lateral dimension is 150 nm and the magnetization is 400 kA / m. Reducing the sensing magnetization 230 of the sensing layer 23 with respect to a given TMR value increases the sensitivity S of the magnetoresistive element 2. Throughout this application, the term "sensing magnetization" is used regardless of whether it refers to "saturated sensing magnetization" or "spontaneous sensing magnetization," where saturation magnetization has the usual meaning of maximum induced magnetic moment.

[0031] From the viewpoint of design rules for a magnetoresistive element 2 that can measure an external magnetic field along an out-of-plane axis substantially perpendicular to the plane of the sensing layer, and has a high operating magnetic field range, low hysteresis, high linearity, and sufficient sensitivity, the results shown above are: The reference layer 21 has a reference magnetization 210 that is oriented substantially perpendicular to the plane of the reference layer 21, and The detection layer 23 has a detection magnetization 230 that has a vortex configuration in the absence of an external magnetic field 60. This suggests the provision of a magnetoresistive element 2. This vortex configuration should have a vortex core 231 magnetization along an out-of-plane axis 50 substantially parallel to the plane of the sensing layer 23 and substantially perpendicular to the plane of the sensing layer 23.

[0032] Furthermore, in terms of design rules for magnetoresistive element 2 having a high operating magnetic field range (such as 60 mT or more), low hysteresis (such as less than 300 pV / V) with respect to the magnitude of the external magnetic field, high linearity (such as an error of less than 2% or 1%), and sufficient sensitivity, the magnetoresistive element 2 is designed to have. The lateral dimension D should be small (or have a high aspect ratio), for example, less than 450 nm, or less than 300 nm, preferably less than 250 nm, or preferably less than 150 nm. The sensing layer 23 should have a small sensing magnetization 230, for example, a sensing magnetization of less than 850 kA / m, preferably less than 600 kA / m, or preferably less than 400 kA / m. Advantageously, the detection layer 23 has a thickness greater than 50 nm, preferably greater than 100 nm.

[0033] From one perspective, the thickness of the detection layer 23 can be increased (50 nm or more), and the detection magnetization 230 of the detection layer 23 may have a value corresponding to a typical saturation magnetization value (e.g., 600 kA / m or more) found in conventional magnetoresistive elements. In the first example (Figure 7), the magnetoresistive element 2 has a lateral dimension D of 250 nm, and the thickness of the detection layer 23 is 110 nm. The ferromagnetic material forming the detection layer 23 may be a ferromagnetic alloy having a detection magnetization 230 of 600 kA / m or more (600 kA / m in this case).

[0034] Preferably, the ferromagnetic material forming the detection layer 23 comprises or consists of a first soft ferromagnetic material having a detection magnetization 230 between 300 and 600 kA / m. The detection magnetization 230 between 300 and 600 kA / m enhances the vertical sensitivity of the magnetoresistive element.

[0035] In one preferred embodiment, the sensing layer 23 has a thickness greater than 60 nm, greater than 70 nm, or greater than 80 nm.

[0036] In another embodiment, the low detection magnetization of the detection layer 23 is set to obtain a low detection magnetization (e.g., less than 600 kA / m). Reducing the thickness (for example, to less than 50 nm), Appropriate selection of ferromagnetic material for forming the detection layer 23 and It is obtained by at least one of the following. In the second example (Figure 8), the magnetoresistive element 2 has a transverse dimension D of 250 nm, and the sensing layer 23 has a thickness of 46 nm and a detection magnetization of 400 kA / m. A low magnetization ferromagnetic alloy may be formed on the sensing layer 23.

[0037] Figures 7 and 8 show that nearly identical magnetization curves are obtained for the magnetoresistive element 2 in the first and second embodiments. In both examples, the emitted magnetic field H expl The nucleation magnetic field H may be approximately 300 mT. nucl It may be approximately 200 mT.

[0038] The magnetoresistive element 2 can have a sensitivity S of 1 mV / V or higher when TMR = 100%. The sensitivity S can be further increased by increasing TMR.

[0039] Referring again to Figure 1, the reference layer 21 may have a composite antiferromagnetic (SAF) structure comprising a first reference sublayer 211 in contact with the tunnel barrier layer 22 and a second reference sublayer 212 separated from the first reference sublayer 211 by a coupling layer 213, where the coupling layer 213 antiferromagnetically couples the first reference sublayer 211 to the second reference sublayer 212. The first and second reference sublayers 211 and 212 each have a PMA such that the reference magnetization 210 is oriented substantially perpendicular to the planes of the first and second reference sublayers 211 and 212 and in opposite directions.

[0040] In the embodiment shown in Figure 9, the first and second reference sublayers 211 and 212 each have a multi-layer structure. In particular, each of the first and second reference sublayers 211 and 212 may comprise a plurality of alternating first metal layers 201 and second metal layers 202. For example, the first metal layer 201 may comprise an ultrathin Co layer, and the second metal layer 202 may comprise an ultrathin Pt layer. The second metal layer 202 preferably contains Pt, but other metals that provide PMA can also be used.

[0041] From one perspective, the ultrathin Co layer 201 may have a thickness between 0.4 nm and 0.6 nm. The ultrathin Pt layer 202 may have a thickness between 0.2 nm and 0.4 nm. The bonding layer 213 may be a Ru layer. While the bonding layer 213 preferably contains Ru, other metals that form RKKY bonds can also be used.

[0042] The reference layer 21, which has an SAF structure as shown in Figure 9, can achieve electric field stability of 300 mT to over 400 mT.

[0043] In another embodiment shown in Figure 10, the detection layer 23 comprises a first detection layer 234 and a second detection layer 235, the second detection layer 235 being located between the first detection layer 234 and the tunnel barrier layer 22 and in contact with the tunnel barrier layer 22. The magnetoresistive element 2 may further include at least a cap layer 25 on top of the first detection layer 234. The second detection layer 235 has a thickness between 1 nm and 5 nm. As described above, the combined thickness of the second detection layer 235 and the first detection layer 234 is greater than 60 nm, so that the detection layer 23 has a thickness greater than 60 nm. The first detection layer 234 contains or consists of a first soft ferromagnetic material. The second detection layer 235 contains or consists of a second soft ferromagnetic material.

[0044] The second detection layer 235 may comprise a single layer containing the second soft ferromagnetic material. Alternatively, the second detection layer 235 may comprise a plurality of second ferromagnetic sublayers 2351, each containing the second soft ferromagnetic material (see Figure 11). Each sublayer may have a thickness between 0.5 nm and 3 nm.

[0045] The second soft ferromagnetic material may contain a CoFeB (cobalt-iron-boron) alloy. In particular, the second soft ferromagnetic material may contain a CoFeB alloy containing 20 to 80 at% Co, 20 to 80 at% Fe, and 0 to 30 at% B.

[0046] In another alternative shown in Figure 12, the second sensing layer 235 comprises a plurality of second ferromagnetic sublayers 2351 located between adjacent second ferromagnetic sublayers 2351, and a second insertion sublayer 2352 of Ta, W, or Ti (tantalum, tungsten, or titanium). The second insertion sublayer 2352 may have a thickness between 0.1 nm and 0.5 nm.

[0047] In yet another alternative shown in Figure 13, the detection layer 23 may include an insertion layer 236 between the second detection layer 235 and the first detection layer 234, containing Ta, W, or Ti, and having a thickness between 0.1 nm and 0.5 nm.

[0048] The first detection layer 234 is configured such that the detected magnetization 230 forms a vortex structure substantially parallel to the plane of the detection layer 23 in the absence of an external magnetic field 60. The first detection layer 234 may contain or be made of a first soft ferromagnetic material.

[0049] Alternatively, the first detection layer 234 may comprise a plurality of first ferromagnetic sublayers 2341 (see Figure 14). Each first ferromagnetic sublayer 2341 may contain or consist of a first soft ferromagnetic material and have a thickness between 0.5 nm and 3 nm. Each first ferromagnetic sublayer 2341 can be separated by a first insertion sublayer 2342 containing Ta, Ti, W, or Ru and having a thickness between 0.05 nm and 0.2 nm.

[0050] The first and second soft ferromagnetic materials can be selected to have a detection layer 23 in which the detected magnetization 230 is 600 kA / m or less, or between 300 and 600 kA / m.

[0051] The first soft ferromagnetic material may contain alloys such as Ni, Fe, Co, and Ni80Fe20at%.

[0052] From one perspective, the first soft ferromagnetic material contains 1 at% to 30 at% of one of Ta, Ti, W, or Ru. Alloying with Ta, Ti, W, or Ru helps to achieve a low detection magnetization of 600 kA / m or less, or between 300 and 600 kA / m. This application offers, for example, the following perspectives. [Perspective 1] A magnetoresistive element (2) comprising a reference layer (21) having a fixed reference magnetization (210), a detection layer (23) having a free detection magnetization (230), and a tunnel barrier layer (22) between the reference layer (21) and the detection layer (23), wherein the magnetoresistive element (2) is configured to measure an external magnetic field (60) oriented substantially perpendicular to the plane of the layers (21, 23), The reference magnetization (210) is oriented substantially perpendicular to the plane of the reference layer (21), The detection magnetization (230) comprises a vortex configuration in the absence of an external magnetic field (60), the vortex configuration having a magnetization direction of the vortex core (231) along an extraplane axis (50) substantially parallel to the plane of the detection layer (23) and substantially perpendicular to the plane of the detection layer (23). Magnetoresistive element (2). [Perspective 2] The magnetoresistive element according to viewpoint 1, wherein the lateral dimension is less than 450 nm, preferably less than 300 nm and less than 250 nm. [Perspective 3] The magnetoresistive element according to viewpoint 1 or 2, wherein the sensing layer (23) has a thickness greater than 60 nm. [Perspective 4] The magnetoresistive element according to any one of viewpoints 1 to 3, wherein the sensing layer (23) has a thickness greater than 80 nm or greater than 100 nm. [Perspective 5] The detection layer (23) comprises a first soft ferromagnetic material, The detection magnetization (230) is 600 kA / mm or less at room temperature, preferably between 300 kA / m and 600 kA / m. A magnetoresistive element described in any one of viewpoints 1 to 4. [Perspective 6] The detection layer (23) comprises a first detection layer (234) comprising a first soft ferromagnetic material and a second detection layer (235) comprising a second soft ferromagnetic material. The detection layer (235) is located between the first detection layer (234) and the tunnel barrier layer (22), and is in contact with the tunnel barrier layer (22). A magnetoresistive element described in any one of viewpoints 1 to 5. [perspective 7] The magnetoresistive element according to viewpoint 6, wherein the second sensing layer (235) comprises a single layer having a thickness between 1 nm and 5 nm. [Perspective 8] The magnetoresistive element according to viewpoint 6, wherein the second sensing layer (235) comprises a plurality of ferromagnetic sublayers (2351), and each ferromagnetic sublayer (2351) has a thickness between 0.5 nm and 3 nm. [Perspective 9] The magnetoresistive element according to viewpoint 7 or 8, wherein the second soft ferromagnetic material comprises a CoFeB alloy or a NifeB alloy. [Perspective 10] The magnetoresistive element according to viewpoint 9, wherein the CoFeB alloy comprises 20 to 80 at% Co, 20 to 80 at% Fe, and 0 to 30 at% B. [Perspective 11] The magnetoresistive element according to any one of views 8 to 10, wherein the second sensing layer (235) further comprises an insertion sublayer (2352) of Ta, W, or Ti between adjacent ferromagnetic sublayers (2351), and the insertion sublayer (2352) has a thickness between 0.1 nm and 0.5 nm. [Perspective 12] The aforementioned detection layer (23) A magnetoresistive element according to any one of views 6 to 11, comprising an insertion layer (236) between the second detection layer (235) and the first detection layer (234) having a thickness between 0.1 nm and 0.5 nm and made of Ta, W, or Ti. [Perspective 13] The first detection layer (234) comprises a plurality of first ferromagnetic sublayers (2341), each first ferromagnetic sublayer having a thickness between 0.5 nm and 3 nm. A magnetoresistive element according to any one of views 6 to 12, wherein the first ferromagnetic sublayer (2341) is separated by a first insertion sublayer (2342) comprising Ta, Ti, W, or Ru and having a thickness between 0.05 nm and 0.2 nm. [Perspective 14] The magnetoresistive element according to any one of views 5 to 13, wherein the first soft ferromagnetic material contains an alloy of at least one of Ni, Fe, and Co. [Perspective 15] The magnetoresistive element according to viewpoint 14, comprising the aforementioned alloy in at% Ni80Fe20. [Perspective 16] The magnetoresistive element according to any one of viewpoints 5 to 14, wherein the first soft ferromagnetic material contains one of the following: Ta, Ti, W, or Ru in a value between 0 at% and 30 at%. [Perspective 17] The aforementioned reference layer (21) The first reference sublayer (211) is in contact with the tunnel barrier layer (22), The second reference sublayer (212) is separated from the first reference sublayer (211) by a coupling layer (213) which antiferromagnetically bonds the first reference sublayer (211) and the second reference sublayer (212). It has a synthetic antiferromagnetic (SAF) structure that includes A magnetoresistive element described in any one of viewpoints 1 to 16. [Perspective 18] The magnetoresistive element according to viewpoint 17, wherein the first reference sublayer (211) and the second reference sublayer (212) each comprise a plurality of alternating first metal layers (201) and second metal layers (202). [Perspective 19] The magnetoresistive element according to viewpoint 18, wherein the first metal layer (201) has a thickness between 0.4 nm and 0.6 nm, and the second metal layer (202) has a thickness between 0.2 nm and 0.4 nm. [perspective 20] Eddy shedding magnetic field (H expl Applying an initial magnetic field until it reaches ) The aforementioned initial magnetic field is a nucleation magnetic field (H) in which the vortex reshapes. nucl The magnetization direction (z, -z) of the vortex core is selected by reducing it to below the vortex emission magnetic field (H expl ) and the nucleation magnetic field (H nucl The selection is determined by the polarity of the following, Measuring the external magnetic field (60) and Equipped with, A method for operating a magnetoresistive element (2) as described in any one of viewpoints 1 to 19. [Perspective 21] Measuring the aforementioned external magnetic field (60) is the same as measuring the aforementioned eddy emission magnetic field (H expl The method described in viewpoint 20, which is performed for external magnetic fields (60) below ). [Explanation of Symbols]

[0053] 2 magnetoresistance element 21 Reference layer 201 1st metal layer 202 2nd metal layer 210 Reference magnetization 211 1st standard sublayer 212 2nd standard sublayer 213 Connecting layer 22 Tunnel barrier layer 23 detection layer 230, Ms detection magnetization 231 Vortex Core 234 First detection layer 2341 First ferromagnetic sublayer 2342 Insertion sublayer 1 235 Second detection layer 2351 Second ferromagnetic sublayer 2352 Second Insertion Sublayer 236 Insertion layer 25 Cap layer 50 Axes outside the plane 60 External magnetic field Branching of magnetization curves A and B B extz External magnetic field along the Z (axis) direction D Horizontal dimension, diameter H expl (vortex) emission magnetic field H nuci Nucleus (generation) field mz magnetization t thickness< / mz> < / mz>

Claims

1. A magnetoresistive element comprising a reference layer having a fixed reference magnetization, a sensing layer having a free sensing magnetization, and a tunnel barrier layer between the reference layer and the sensing layer, wherein the magnetoresistive element is configured to measure an external magnetic field oriented substantially perpendicular to the plane of the layer. The reference magnetization is oriented substantially perpendicular to the plane of the reference layer, The detection magnetization comprises a vortex configuration in the absence of an external magnetic field, the vortex configuration having a magnetization direction of the vortex core along an extraplane axis substantially parallel to the plane of the detection layer and substantially perpendicular to the plane of the detection layer. The aforementioned detection layer has a thickness greater than 60 nm. The detection layer comprises a first soft ferromagnetic material having the detection magnetization between 300 and 600 kA / m. The detection layer comprises a first detection layer comprising a first soft ferromagnetic material and a second detection layer comprising a second soft ferromagnetic material. The second detection layer is located between the first detection layer and the tunnel barrier layer, and is in contact with the tunnel barrier layer. The second detection layer comprises a plurality of second ferromagnetic sublayers, each ferromagnetic sublayer having a thickness between 0.5 nm and 3 nm. Magnetoresistive element.

2. The magnetoresistive element according to claim 1, wherein the lateral dimension is less than 450 nm.

3. The magnetoresistive element according to claim 1, wherein the lateral dimension is less than 300 nm.

4. The magnetoresistive element according to claim 1, wherein the lateral dimension is less than 250 nm.

5. The magnetoresistive element according to claim 1, wherein the sensing layer has a thickness greater than 60 nm.

6. The magnetoresistive element according to claim 1, wherein the sensing layer has a thickness greater than 80 nm or greater than 100 nm.

7. The magnetoresistive element according to claim 1, wherein the second sensing layer comprises a single layer having a thickness between 1 nm and 5 nm.

8. The magnetoresistive element according to claim 7, wherein the second soft ferromagnetic material comprises a CoFeB alloy.

9. The aforementioned CoFeB alloy contains 20 to 80 at% Co and 20 to 80 at% Fe, The magnetoresistive element according to claim 8, comprising B in a range of 0 to 30 at%.

10. The second detection layer further comprises an insertion sublayer of Ta, W, or Ti between adjacent ferromagnetic sublayers. The magnetoresistive element according to claim 1, wherein the insertion sublayer has a thickness between 0.1 nm and 0.5 nm.

11. The aforementioned detection layer The magnetoresistive element according to claim 1, further comprising an insertion layer of Ta, W, or Ti having a thickness between 0.1 nm and 0.5 nm between the second detection layer and the first detection layer.

12. The first detection layer comprises a plurality of first ferromagnetic sublayers, each first ferromagnetic sublayer having a thickness between 0.5 nm and 3 nm. The magnetoresistive element according to claim 1, wherein the first ferromagnetic sublayer is separated by a first insertion sublayer comprising Ta, Ti, W, or Ru and having a thickness between 0.05 nm and 0.2 nm.

13. The magnetoresistive element according to claim 1, wherein the first soft ferromagnetic material contains an alloy of at least one of Ni, Fe, and Co.

14. The magnetoresistive element according to claim 13, wherein the alloy comprises Ni80Fe20 in at%.

15. The magnetoresistive element according to claim 1, wherein the first soft ferromagnetic material contains one of Ta, Ti, W, or Ru in a value between 0 at% and 30 at%.

16. The aforementioned reference layer, The first reference sublayer adjacent to the tunnel barrier layer, The magnetoresistive element according to claim 1, comprising a composite antiferromagnetic (SAF) structure including a second reference sublayer separated from the first reference sublayer by a coupling layer that antiferromagnetically bonds the first reference sublayer and the second reference sublayer.

17. The magnetoresistive element according to claim 16, wherein the first reference sublayer and the second reference sublayer each comprise a plurality of alternating first metal layers and second metal layers.

18. The magnetoresistive element according to claim 17, wherein the first metal layer has a thickness between 0.4 nm and 0.6 nm, and the second metal layer has a thickness between 0.2 nm and 0.4 nm.

19. Applying an initial magnetic field until it reaches the eddy emission magnetic field, The process of selecting the magnetization direction of the vortex core by reducing the initial magnetic field to a level below the nucleation magnetic field that reforms the vortex, wherein the magnetization direction of the vortex core is determined by the polarity of the vortex emission magnetic field and the nucleation magnetic field, Measuring the external magnetic field and Equipped with, A method for operating a magnetoresistive element as described in claim 1.

20. The method according to claim 19, wherein the measurement of the external magnetic field is performed for an external magnetic field that is lower than the eddy emission magnetic field.

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