JP2008286739A - Magnetic field detector, and rotation angle detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic field detector of excellent productivity, capable of compactifying a size without narrowing excessively a magnetic field detection range, and capable of detecting multi-axial directions, and a rotation angle detector using the magnetic field detector. <P>SOLUTION: This magnetic field detector is formed, on a substrate, with a fixed layer 9 with a magnetization direction fixed by an antiferromagnetic layer 8, a free layer 11 with a magnetization direction varied by an applied external magnetic field, and the first magneto-resistive effect element 1a and the second magneto-resistive effect element 1b having respectively tunnel insulating layers arranged between the fixed layer 9 and the free layer 11. A blocking temperature on a junction face between the antiferromagnetic layer 8 and the fixed layer 9 in the first magneto-resistive effect element is different from a blocking temperature on a junction face between the antiferromagnetic layer 8 and the fixed layer 9 in the second magneto-resistive effect element, and the magnetization direction of the fixed layer 9 in the first magneto-resistive effect element 1a is different from the magnetization direction of the fixed layer 9 in the second magneto-resistive effect element 1b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic field detector and a rotation angle detection device that perform magnetic field detection using a magnetoresistive effect element.

  In recent years, application of a tunnel magnetoresistive element (TMR element) to a memory or a magnetic head has been studied.

  The TMR element has a three-layer film structure composed of a ferromagnetic layer / insulating layer / ferromagnetic layer sandwiching an insulating layer between two ferromagnetic layers. By setting the spins of the two ferromagnetic layers parallel or antiparallel to each other by an external magnetic field, the magnitude of the tunnel current flowing through the insulating layer in the direction perpendicular to the film surface changes, that is, the TMR effect is reduced. Use.

  For example, Patent Document 1 shows an example in which a spin valve TMR element is applied to a magnetic head. One ferromagnetic layer is exchange-coupled with the antiferromagnetic layer, and the magnetization of the ferromagnetic layer is fixed regardless of an externally applied magnetic field. This forms a so-called fixed layer. The other ferromagnetic layer is used as a free layer whose magnetization is freely rotated according to an external magnetic field. In the pinned layer, a nonmagnetic layer is inserted as a spacer layer between the ferromagnetic layers to cause antiferromagnetic coupling in these ferromagnetic layers and set the magnetizations of these ferromagnetic layers in the antiparallel direction. . The antiparallel magnetic field of the pinned layer cancels out the leakage magnetic field from the pinned layer, reduces the influence of the leakage magnetization on the free layer, and enables highly sensitive magnetic field detection.

  A magnetic field detector that detects an external magnetic field not only detects a magnetic field in one axis direction, but also has an application for detecting a magnetic field in two or three axes. Patent Document 2 shows an example in which a magnetic field detector capable of detecting a magnetic field in two axial directions is formed on the same substrate to improve mass productivity. The two magnetoresistive elements are arranged so that the longitudinal direction forms an angle of 90 degrees, and uniaxial anisotropy in the 45 degree direction is given to the two magnetoresistive elements, so that 2 on the same substrate. A magnetic field detector capable of detecting an axial magnetic field could be manufactured.

Japanese Patent Laid-Open No. 7-169026 (Steps 0017 to 0019, FIG. 5) Japanese Patent Laying-Open No. 2006-208020 (0012 stage to 0013 stage, FIG. 2)

  To configure a magnetic field detector that detects a magnetic field in two or three axes using the TMR element disclosed in Patent Document 1, the TMR element disclosed in Patent Document 1 is uniaxial (one-dimensional). Therefore, the two TMR elements are combined to detect the magnetic field in the biaxial direction, and the three TMR elements are combined to detect the magnetic field in the triaxial direction. Therefore, it is difficult to reduce the size of a magnetic field detector that can detect magnetic fields in multi-axis directions because it is necessary to combine individual TMR elements, and the arrangement and axis adjustment of each element in the magnetic field detector are difficult. However, there is a problem in that mass production is inferior.

  The magnetic field detector that can detect the magnetic field in the biaxial direction shown in Patent Document 2 is uniaxially anisotropic in the 45 degree direction with respect to the two magnetoresistive elements arranged so that the longitudinal direction forms an angle of 90 degrees. It was manufactured by a method of imparting sex. However, this method has a problem that the magnetic field strength measurement range of each of the two magnetoresistive elements is narrow compared to the case where uniaxial anisotropy is imparted in the short direction. When such a method is applied to a TMR element, the angle between the fixed layer and the free layer of each TMR element when there is no magnetic field cannot be individually optimized, so the center of resistance change of the TMR element when there is no magnetic field. There is a problem that the magnetic field intensity that can not be made near, the magnetic field intensity that can be detected in the positive and negative directions of the magnetic field cannot be made uniform, and the measurement range of the magnetic field detector must be narrowed.

  When the magnetic field detector is applied to, for example, a rotation angle detection device that detects a rotation angle, if the TMR element disclosed in Patent Document 1 is used, there is a problem that the magnetic field detection device cannot be sufficiently miniaturized. If the magnetic field detector shown is used, there is a possibility that a non-detection region of the magnetic field detection device may be generated depending on the arrangement position, and there arises a problem that restrictions on use increase.

  The present invention has been made in order to solve the above-described problems. A magnetic field detector capable of detecting a multi-axis magnetic field that can be miniaturized and has excellent mass productivity without extremely narrowing the magnetic field detection range. An object of the present invention is to provide a rotation angle detection device using the magnetic field detector.

  The magnetic field detector according to the present invention includes a pinned layer whose magnetization direction is fixed by an antiferromagnetic layer, a free layer whose magnetization direction is changed by an externally applied magnetic field, and a tunnel disposed between the pinned layer and the free layer. A first magnetoresistive element and a second magnetoresistive element each having an insulating layer are formed on the substrate. The blocking temperature at the interface between the antiferromagnetic layer and the pinned layer of the first magnetoresistive element is different from the blocking temperature at the interface between the antiferromagnetic layer and the pinned layer of the second magnetoresistive element, and The magnetization direction of the pinned layer in the magnetoresistive effect element is different from the magnetization direction of the pinned layer in the second magnetoresistive effect element.

  In the magnetic field detector according to the present invention, the first magnetoresistive element and the second magnetoresistive element have different blocking temperatures at the interface between the antiferromagnetic layer and the pinned layer, and the magnetization direction of the pinned layer is different. By being different from each other, it is possible to obtain a magnetic field detector capable of detecting a magnetic field in a multi-axis direction that can be downsized and is excellent in mass productivity without extremely narrowing the magnetic field detection range.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a schematic configuration of a magnetic field detector according to Embodiment 1 of the present invention, and FIG. 2 is a diagram showing an electrical equivalent circuit of the magnetic field detector shown in FIG. In FIG. 1, the magnetic field detector includes a magnetoresistive effect element 1 that uses the TMR effect, a DC power source 2 that supplies a constant current of a predetermined magnitude to the magnetoresistive effect element 1, and the magnetoresistive effect element 1. It comprises a voltmeter 3 that detects the voltage between the electrodes. The DC power supply 2 and the voltmeter 3 are, for example, an upper electrode layer (not shown) and a lower electrode layer (not shown) of the magnetoresistive effect element 1 through wirings 4 and 5 made of aluminum (Al). ) Respectively.

  The magnetoresistive effect element 1 includes a pinned layer 9, a free layer 11, and a tunnel insulating layer 10 disposed between the free layer 11 and the pinned layer 9 as main parts. The magnetoresistive effect element 1 has a substantially planar shape formed in a rectangular shape, and has a longitudinal direction and a short direction. The pinned layer 9 is magnetized in the short direction, and the magnetization direction is fixed. The magnetization direction of the free layer 11 is directed to the magnetization direction 15a, that is, the longitudinal direction when the external magnetic field Hex is 0 Oe in the absence of a magnetic field. Depending on the magnetization direction of the external magnetic field Hex, the magnetization direction of the free layer 11 rotates, for example, in the magnetization direction 15b.

  As shown in FIG. 1, the magnetoresistive effect element 1 is set so that the magnetization direction 16 of the pinned layer 9 and the magnetization direction of the free layer 11 are orthogonal to each other when there is no magnetic field, and the resistance value in the no magnetic field state is set to the element resistance center. As a value, the element resistance changes between a high resistance state and a low resistance state according to the intensity and direction of the external magnetic field, and the external magnetic field Hex is detected with high sensitivity. In the magnetic detector of FIG. 1, a change in resistance value of the magnetoresistive effect element 1 through which a constant current flows is measured by a voltage value.

  FIG. 3 is a diagram more specifically showing a cross-sectional structure of the magnetoresistive effect element shown in FIG. In FIG. 3, the magnetoresistive effect element 1 includes an insulating layer 14 on the surface of a substrate 13, a lower electrode layer 6 formed thereon, and a base layer 7 formed on the surface of the lower electrode layer 6. An antiferromagnetic layer 8 is formed on the surface of the underlayer 7, and a fixed layer 9 is formed on the antiferromagnetic layer 8. The magnetization direction of the pinned layer 9 is fixed by the antiferromagnetic layer 8. A tunnel insulating layer 10 is formed on the fixed layer 9, and a free layer 11 is formed on the tunnel insulating layer 10. An upper electrode layer 12 is formed on the surface of the free layer 11. Here, the antiferromagnetic layer 8 includes a lower antiferromagnetic layer 8a formed on the underlayer 7 and an upper antiferromagnetic layer 8b formed on the lower antiferromagnetic layer 8a. The pinned layer 9 includes a lower ferromagnetic layer 9a in contact with the antiferromagnetic layer 8, a nonmagnetic layer 9b formed on the lower ferromagnetic layer 9a, and an upper layer strength formed on the nonmagnetic layer 9b. The magnetic layer 9c is used.

  The magnetization direction 16 of the pinned layer 9 shown in FIG. 1 corresponds to the magnetization direction 16a of the lower ferromagnetic layer 9a in the pinned layer 9 shown in FIG. The magnetization direction of the upper ferromagnetic layer 9c in the fixed layer 9 is the magnetization direction 16b due to antiferromagnetic coupling between an upper ferromagnetic layer 9c and a lower ferromagnetic layer 9a described later.

  Next, the configuration of each layer will be described in detail. The substrate 13 is, for example, a silicon substrate, and the insulating layer 14 is, for example, a silicon oxide film.

  The lower electrode layer 6 and the upper electrode layer 12 are each composed of a tantalum (Ta) film having a thickness of 10 nm. The lower electrode layer 6 is connected to the wiring 5 shown in FIG. 1, and the upper electrode layer 12 is connected to the wiring 4 shown in FIG.

  The underlayer 7 is a nickel-iron film (Ni-Fe film) and has a thickness of 2 nm. The underlayer 7 is formed in order to control the crystal orientation of the lower antiferromagnetic layer 8a formed thereon, and is a buffer layer against lattice mismatch between the lower electrode layer 6 and the lower antiferromagnetic film 8a. Function as.

  The antiferromagnetic layer 8 includes a lower antiferromagnetic layer 8a made of an iridium-manganese film (Ir-Mn film) and an upper antiferromagnetic layer 8b made of a platinum-manganese film (Pt-Mn film). Each film thickness is 10 nm.

  The ferromagnetic layers 9a and 9c used for the pinned layer 9 are composed of a cobalt-iron film (Co-Fe film). The lower ferromagnetic layer 9a is a ferromagnetic layer and is laminated in contact with the antiferromagnetic layer 8, whereby the magnetization direction 16 is fixed. That is, the antiferromagnetic layer 8 fixes the spin direction of the lower ferromagnetic layer 9a. Further, in order to reduce the influence of magnetostatic coupling between the pinned layer 9 and the free layer 11, the pinned layer 9 has a three-layer structure composed of a ferromagnetic layer / nonmagnetic layer / ferromagnetic layer, and these ferromagnetic layers are connected to each other. It is magnetized in the antiparallel direction to realize antiferromagnetic coupling. Therefore, the upper ferromagnetic layer 9c faces in the opposite direction to the lower ferromagnetic layer 9a. Each of the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c has a thickness of 3 nm. The nonmagnetic layer 9b is made of ruthenium (Ru) and has a thickness of 0.8 nm.

The tunnel insulating layer 10 is composed of an aluminum oxide (Al ₂ O ₃ ) film, and the film thickness is 2.2 nm.

  The free layer 11 is composed of a Ni—Fe film and has a thickness of 5 nm. Since the free layer 11 is required to change the magnetization direction sensitively to an external magnetic field, it is preferably a soft magnetic material.

  Next, a method for manufacturing the magnetoresistive effect element 1 shown in FIG. 3 will be described. FIG. 4 is an element arrangement view of the produced biaxial magnetic field detection element as seen from above the substrate surface. Magnetoresistive elements 1 whose resistances are changed by an external magnetic field are respectively formed in the element region A and the element region B in the element arrangement diagram. As an example of the shape of the magnetoresistive effect element 1, it is assumed that the short side × long side is a rectangle of 4 μm × 64 μm. The magnetoresistive effect element 1 created in the element region A and the element region B will be referred to as an element A and an element B. Region C is an element isolation region in which element A, element B, and lower wiring layer 6 do not exist. Actually, the wiring layer 4 connected to the upper electrode 12 of the element A and the element B and the contact portion exist, but are omitted here. The magnetization directions of the fixed layers 9 in the element A and the element B are shown in the drawing. The element A is magnetized in the Ha direction, the element B is magnetized in the Hb direction, and the magnetization directions Ha and Hb are orthogonal to each other.

  Next, a manufacturing method is demonstrated using the cross-sectional structure cut | disconnected by the KK plane shown in FIG. 5 is a diagram showing a cross-sectional structure of the biaxial magnetic field detection element cut along the KK plane of FIG. 4, and FIG. 6 is a diagram showing the manufacturing process of FIG.

  This will be described with reference to FIG. On the substrate 13, for example, a silicon oxide film having a thickness of 500 nm is deposited as the insulating layer 14, and a Ta film having a thickness of 10 nm is formed as the lower electrode layer 6 by using, for example, a DC magnetron sputtering method. Next, a Ni—Fe film having a thickness of 2 nm is deposited on the base electrode layer 6 to form a base layer 7 for controlling the crystal orientation of the ferromagnetic film formed in the upper layer. Subsequently, the Ir—Mn film of the lower antiferromagnetic layer 8 a and the Pt—Mn film of the upper antiferromagnetic layer 8 b are successively deposited on the underlayer 7 to form the antiferromagnetic layer 8. Thereafter, a resist is applied and patterned to form a resist mask 17. As a result, the structure shown in FIG.

  Thereafter, only the Pt—Mn film of the upper antiferromagnetic layer 8b is etched, and then the resist is removed, whereby in the element regions B and C, the antiferromagnetic layer having only the Ir—Mn film, that is, the lower layer antiferromagnetic layer is obtained. A ferromagnetic layer 8a is formed, and in the element region A, a laminated antiferromagnetic layer in which the Pt—Mn film remains on the Ir—Mn film is formed, and the structure shown in FIG. 6B is obtained.

Further, on the surface of the antiferromagnetic layer 8, a Co—Fe film / Ru film / Co—Fe film is formed in the order of film thickness 3 nm / 0.8 nm / 3 nm, and after forming the pinned layer 9, tunnel insulation is performed. An Al ₂ O ₃ film as the layer 10 is formed. A 5 nm thick Ni—Fe film is formed on the tunnel insulating layer 10 to form the free layer 11. Further, a Ta film is formed using a DC magnetron sputtering method, and the upper electrode layer 12 is formed.

  Next, a pattern corresponding to the magnetoresistive effect element 1 of each of the element A and the element B is formed by the resist mask 17 to obtain the structure shown in FIG.

  Thereafter, etching is performed using the resist mask 17 to obtain the structure shown in FIG. FIG. 6D shows a case where the etching stop surface is the antiferromagnetic layer 8. For the etching here, it is necessary that the conductive portion formed on the tunnel insulating layer 10 is removed and the lower electrode layer 6 is not removed. Any of the electrode layer 6, the underlayer 7, the antiferromagnetic layer 8, and the pinned layer portion 9 may be used, but the tunnel insulating film 10 is more preferable as the etching stop surface from the viewpoint of suppressing leakage at the element side wall.

  After removing the resist mask 17, a pattern for etching the lower electrode layer is formed again with the resist, and the lower electrode layer 6 is etched. Specifically, element isolation is performed by exposing the insulating layer 14 of the silicon oxide film in the region C. Thereafter, an interlayer insulating film 18 is formed, and contact holes are formed, and contact plugs 19 and wirings 4a, 5a, 4b, and 5b are formed by an Al film, thereby obtaining the structure shown in FIG. Here, the wirings 4a and 5a are the wirings 4 and 5 in the element A, respectively, and the wirings 4b and 5b are the wirings 4 and 5 in the element B, respectively.

  A method for determining the magnetization direction 16 of the pinned layer 9 will be described. First, after describing the characteristics of the magnetization direction of the pinned layer 9, a method applied to the first embodiment will be described.

  The case where the lower ferromagnetic layer 9a is deposited on the antiferromagnetic layer 8 made of a single layer in a magnetic field will be described. The lower ferromagnetic layer 9 a is exchange coupled with the antiferromagnetic layer 8. For example, it is assumed that the magnetization direction of the lower ferromagnetic layer 9a is the magnetization direction 16a shown in FIG. Thereafter, the magnetization direction maintains the magnetization direction 16a even after the nonmagnetic layer 9b and the upper ferromagnetic layer 9c are formed. Specifically, the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c form antiferromagnetic coupling with each other through the nonmagnetic layer 9b, and the magnetization directions of the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c are opposite to each other. The direction is maintained.

  The above-described exchange coupling loses the effect of exchange coupling when the blocking temperature is exceeded at a temperature lower than the Neel temperature, and the magnetization direction of the lower ferromagnetic layer 9a is not restricted by the antiferromagnetic layer 8. In other words, the magnetization direction of the lower ferromagnetic layer 9a in the pinned layer 9 is changed to the direction of the applied magnetic field by performing heat treatment on the pinned layer 9 in an applied magnetic field higher than the saturation magnetic field in a state higher than the blocking temperature. Can be directed. Then, by lowering the temperature in the applied magnetic field, exchange coupling with the antiferromagnetic layer 8 is formed while maintaining the magnetization direction. Here, the blocking temperature is a temperature at which the bias magnetic field that fixes the magnetization direction of the ferromagnetic layer by the antiferromagnetic layer disappears.

  In the first embodiment, since two types of lower antiferromagnetic layer 8a and upper antiferromagnetic layer 8b are used, a plurality of heat treatments are performed at different temperatures during the heat treatment in the magnetic field. Specifically, it is performed as follows. First, a magnetic field of 5 kOe is applied in the Ha direction (X direction) shown in FIG. 4, and this state is maintained at 300 ° C. for 3 hours. As a result, the lower ferromagnetic layer 9a in the pinned layer 9 has magnetization in the Ha direction. By cooling while applying a magnetic field in the Ha direction, the lower ferromagnetic layer 9a in the pinned layer 9 has magnetization in the Ha direction in both the element A and the element B, and has exchange coupling with the anti-comagnetic layer 8.

  Next, heat treatment is performed at 260 ° C. for 1 hour while applying a magnetization of 5 kOe in the Hb direction (Y direction) shown in FIG. Although this temperature is higher than the blocking temperature between the Ir—Mn film (lower antiferromagnetic layer 8a) and the Co—Fe film, it is higher than the blocking temperature between the Pt—Mn film (upper antiferromagnetic layer 8b) and the Co—Fe film. Low. Therefore, in element A, exchange coupling between the Pt—Mn film (upper antiferromagnetic layer 8b) and the Co—Fe film is maintained, but in element B, the Ir—Mn film (lower antiferromagnetic layer 8a). And exchange coupling between the Co—Fe films are not retained. Therefore, in the element B, the lower ferromagnetic layer 9a in the pinned layer 9 has magnetization in the Hb direction, and causes exchange coupling with the Ir—Mn film (lower antiferromagnetic layer 8a) during cooling. As a result, the lower ferromagnetic layer 9a having magnetization in the Ha direction can be formed in the element A, and the lower ferromagnetic layer 9a having magnetization in the Hb direction can be formed in the element B.

  As described above, since the element A and the element B are configured such that the blocking temperature between the lower ferromagnetic layer 9a and the antiferromagnetic layer 8 is different, the lower ferromagnetic layer 9a can be magnetized in a desired direction. it can.

  The upper ferromagnetic layer 9c is magnetized antiparallel to the lower ferromagnetic layer 9a via the nonmagnetic layer 9b formed of a Ru film, and is antiferromagnetically coupled. As a result, the lower ferromagnetic layer 9a in the pinned layer 9 having magnetization in the X axis direction, that is, the short direction can be formed in the element A, and the lower layer strong layer in the pinned layer 9 having magnetization in the Y axis direction, that is, the short direction can be formed in the element B. The magnetic layer 9a can be formed.

  The film thicknesses of the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c are both 3 nm. Accordingly, since the two lower ferromagnetic layers 9a and the upper ferromagnetic layer 9c coupled in antiparallel have the same thickness and the same magnetic field strength, the leakage magnetic fields of the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c are the same. Are opposite in direction and substantially cancelled. In the case of the magnetoresistive effect element 1 shown in FIG. 3, the leakage magnetic field in the pinned layer 9 is canceled by the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c, and the magnetostatic coupling between the pinned layer 9 and the free layer 11 is suppressed. it can. As a result, the free layer 11 of the magnetoresistive effect element 1 is not affected by the leakage magnetic field from the pinned layer 9, so that the magnetization is oriented in the longitudinal direction due to the shape magnetic anisotropy when there is no magnetic field. The directions of magnetization of the pinned layer 9 and the free layer 11 can be orthogonalized without performing any additional processing on the free layer 11. In addition, by shifting the magnetization direction of the pinned layer 9 from the short direction, the magnetization directions of the pinned layer 9 and the free layer 11 can be set to arbitrary angles.

  As described above, in the magnetoresistive effect element 1, magnetostatic coupling between the pinned layer 9 and the free layer 11 can be suppressed, and the magnetization directions of the pinned layer 9 and the free layer 11 in the absence of a magnetic field are effectively orthogonal. Which can be substantially orthogonal. Thereby, at the time of no magnetic field (0 Oe), the element resistance value of the magnetoresistive effect element 1 can obtain the center value Rm in the resistance value R of the element resistance. Therefore, when a constant current I is passed through the magnetoresistive effect element 1, as shown in FIG. 7, the output voltage Vm at no magnetic field (0 Oe) is I × Rm, and the center values of the output voltages Va and Vb are Obtainable. As a result, when there is no magnetic field (0 Oe), the resistance value R of the magnetoresistive element 1 can be set to the center value Rm, so that the magnetic field strength that can be detected in the positive direction and the negative direction of the magnetic field can be made uniform, and the magnetic field detector can be measured. The range can be set to maximum. Here, the voltage Va is a voltage when the magnetization direction of the free layer 11 is parallel to the magnetization direction of the lower ferromagnetic layer 9a in the fixed layer 9 and the resistance value R is minimized. The voltage Vb is a voltage when the magnetization direction of the free layer 11 is antiparallel to the magnetization direction of the lower ferromagnetic layer 9a in the pinned layer 9 and the resistance value R is maximized.

  Further, the fixed layer 9 having the three-layer structure as described above suppresses the leakage magnetic field of the fixed layer caused by the film thickness of the ferromagnetic layer, which is a problem in the case of a fixed layer composed of a single layer. Even if a plurality of elements are formed on the same substrate, the element resistance at the time of no magnetic field does not vary among the elements, and the center value Rm of the resistance value R of the element resistance at the time of no magnetic field can be obtained. FIG. 7 is a magnetic field / output voltage characteristic curve of the magnetic field detector configured as shown in FIG. The output voltage on the vertical axis is shown in arbitrary units.

Next, the output voltage of the magnetic field detector shown in FIG. 1 will be described. During operation of the magnetic field detector, a current I having a constant current value is supplied from the DC power source 2 to the magnetoresistive effect element 1. In the magnetoresistive effect element 1, an ideal state where there is no magnetic interaction between the pinned layer 9 and the free layer 11 is considered. When the external magnetic field Hex is applied in the same direction as the magnetization direction 16 of the pinned layer 9, the resistance value R of the element resistance of the magnetoresistive effect element 1 when the external magnetic field Hex is applied is expressed by the following equation (1).
R = Rm + (ΔR / 2) × (| H | / | Hk |) (1)
Here, Rm represents the center value of the resistance value R of the magnetoresistive effect element 1 when the external magnetic field Hex is 0 Oe, that is, no magnetic field, and ΔR represents the magnetoresistance change rate of the magnetoresistive effect element 1. Hk indicates the magnetic field strength of the saturation magnetic field of the free layer 11, and H indicates the magnetic field strength of the external magnetic field Hex.

Since the current I having a constant current value is supplied to the magnetoresistive effect element 1 and the resistance value is R, the following equation (2) is established between both electrodes of the magnetoresistive effect element 1, that is, between the wirings 4 and 5. ) Is generated.
V = I × (Rm + (ΔR / 2) × (| H | / | Hk |)) (2)
The resistance values of the wirings 4 and 5 are two orders of magnitude smaller than the resistance value R of the magnetoresistive effect element 1 and can be ignored. From the relationship expressed by the above formulas (1) and (2), the intensity of the external magnetic field Hex can be detected by measuring the voltage V applied to the magnetoresistive effect element 1 with the voltmeter 3.

  When the magnetic field detector serving as the electrical equivalent circuit shown in FIG. 8 is configured using the biaxial magnetic field detection element shown in FIG. 4, the element A and the element B are expressed by the equation (2) according to the magnetic field received by each of them. The voltage shown in is output. In FIG. 8, the magnetoresistive effect element 1a corresponding to the element A is connected to the DC power supply 2a and the voltmeter 3a, and the magnetoresistive effect element 1b corresponding to the element B is connected to the DC power supply 2b and the voltmeter 3b. .

For example, consider a case where the external magnetic field Hex exists in the direction shown in FIG. An external magnetic field Hex having a magnetic field strength of H is incident on the biaxial magnetic field detection element at an angle α with respect to the X axis. The element A detects Hex-x that is an X-axis component, and the element B detects Hex-y that is a Y-axis component. The strength C of Hex-x and the strength D of Hex-y are expressed by the following equations (3) and (4), respectively.
C = H × cosα (3)
D = H × sin α (4)

From the above equations (3) and (4), the magnetic field strength H and the angle α of the external magnetic field Hex are expressed by the following equations (5) and (6), respectively.
H = √ (C ² + D ² ) (5)
α = cos ⁻¹ (C / √ (C ² + D ² )) (6)

  As described above, since the magnetic field detector according to the first embodiment has the magnetoresistive effect element 1 having the biaxially fixed layers orthogonal to each other in the element, the magnetic field strength H in the respective axial directions. And the incident angle α can be detected. That is, a magnetic field in the biaxial direction can be detected. Further, the magnetoresistive effect element 1 for detecting the magnetic field components of the two axes constituting the two axes can be disposed close to the same substrate, and the magnetic field detector for detecting the magnetic field in the two-axis direction can be downsized. Can do. Furthermore, it is possible to incorporate a signal processing circuit that receives the output voltage of the biaxial magnetic field detection element and performs various processes on the substrate on which the biaxial magnetic field detection element for detecting the biaxial magnetic field is formed. . In this case, a multifunctional processing apparatus including a magnetic detection function can be reduced in size.

  In the case of configuring a magnetic field detector that cuts out the magnetoresistive effect elements 1a and 1b and detects a magnetic field in the biaxial direction, three electrode pads may be provided. The three electrode pads are an electrode pad connected to the wiring 4a connected to the upper electrode layer 12 of the element A, an electrode pad connected to the wiring 4b connected to the upper electrode layer 12 of the element B, and a lower part of the element A This is an electrode pad for commonly connecting the wiring 5 a connected to the electrode layer 6 and the wiring 5 b connected to the lower electrode layer 6 of the element B. On the other hand, when a magnetic field detector that detects a magnetic field in two axes is configured by combining a magnetic field detector that detects a magnetic field in one axis, four electrode pads are required. Only one portion and the reduction due to the close proximity of each element can be reduced.

  Unlike the case where a magnetic field detector that detects a biaxial direction is configured by combining magnetic field detectors that detect a magnetic field in one axial direction, each magnetoresistive effect element 1 is created on the same substrate. After completion, the arrangement of each element and the work process of adjusting the axis are unnecessary, and the mass productivity can be improved.

  As described above, the magnetic field detector according to the first embodiment is antiferromagnetic in the first magnetoresistance effect element 1a (element A) and the second magnetoresistance effect element 1b (element B) arranged on the same substrate. Since the blocking temperature at the bonding surface between the layer and the fixed layer is different, and the magnetization direction of the fixed layer is different, the magnetic field detector that detects the magnetic field in the biaxial direction can be reduced in size, and mass production The magnetic field detector which can detect the magnetic field of the biaxial direction excellent in property is obtained. Further, by configuring as described above, the characteristic curve of the magnetic field / output voltage of each axis can be individually optimized. Thus, unlike the case where a non-detection region such as the magnetic field detector shown in Patent Document 2 may be generated, the magnetic field detection range is not extremely narrowed and the magnetic field detection range is widened. Can do.

  Further, the magnetic field detector for detecting the biaxial direction in the first embodiment by arranging the magnetoresistive effect element 1 for detecting the magnetic field component of each axis constituting the two axes on the same substrate is a single axis. The magnetoresistive effect element 1 for detecting the magnetic field component of each axis can be arranged closer to that in the case where the magnetic field detector for detecting the biaxial direction is configured by combining the magnetic field detectors for detecting the magnetic field in the direction. . Therefore, the magnetic field detection target area (area including each magnetoresistive effect element 1) is reduced, so that the detection error can be reduced and the magnetic field distribution can be detected in detail.

  In addition, the magnetic field detector according to the first embodiment can detect current, detect a position, and detect rotation by detecting a magnetic field. The present invention can also be applied to an electric circuit including the magnetic field detector according to the first embodiment. In current detection, a magnetic field generated by current is detected. In position detection, a magnetic field distribution in which a position is related to a predetermined magnetic field is detected. In rotation detection, the magnetic field of a rotating magnet is detected.

  The nonmagnetic layer 9b is not limited to a Ru film. The nonmagnetic layer 9b is only required to realize strong antiferromagnetic coupling between the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c, and is preferably a 3d transition metal film. Therefore, a 3d transition metal film other than the Ru film may be used. The film thickness is not limited to 0.8 nm as long as the antiferromagnetic coupling between the lower ferromagnetic layer 9a and the upper ferromagnetic layer 9c can be maintained.

  Moreover, the shape of the magnetoresistive effect element 1 does not need to be rectangular, and any shape can be used by imparting magnetocrystalline anisotropy or induced magnetic anisotropy.

  In addition, the blocking temperature was changed by using a different material for the antiferromagnetic layer. However, the blocking temperature can also be changed by changing the material for the pinned layer or both materials. It is.

  As shown in FIG. 5, in the element A, a stacked structure of a Pt—Mn film and an Ir—Mn film is used. In the element A, the antiferromagnetic layer 8 is made only of the Pt—Mn film. Patterning may be performed after forming the Mn film. In that case, the cross-sectional structure of the biaxial magnetic sensing element shown in FIG. 5 is as shown in FIG. 10, and the magnetization directions of the element A and the element B are different in different single antiferromagnetic layers. A retained anchoring layer is present. In this case, the height of the element A and the element B can be made substantially equal, and the exposure state of the resist can be made equal for both the element A and the element B, so that the processing accuracy of the element A and the element B can be increased.

  Further, although the magnetization directions of the element A and the element B of the biaxial magnetic detection element are orthogonal to each other, they may be in different directions on the same plane. It is possible to calculate the X-axis direction and the Y-axis direction orthogonal to each other from the detection voltages of these two elements.

Embodiment 2. FIG.
FIG. 11 is a diagram showing an electrical equivalent circuit of a magnetic field detector for detecting a magnetic field in the triaxial direction according to Embodiment 2 of the present invention. FIG. 12 is a diagram showing a schematic configuration of the triaxial magnetic field detection element in the second embodiment. FIG. 12A is a perspective view, and FIG. 12B is a cross-sectional view of FIG. In FIG. 11, the magnetoresistive effect element 1e corresponding to the element E is connected to the DC power supply 2e and the voltmeter 3e, and the magnetoresistive effect element 1f corresponding to the element F is connected to the DC power supply 2f and the voltmeter 3f. The magnetoresistive effect element 1g corresponding to the element G is connected to the DC power source 2g and the voltmeter 3g. The magnetic detector in the first embodiment is different in that three magnetoresistive effect elements 1 are arranged on the same substrate and a magnetic field in three axial directions can be detected.

  The substrate 13 is formed with inclined surfaces 13b and 13c inclined with respect to the main surface 13a. Two magnetoresistive effect elements 1e (element E) and magnetoresistive effect element 1f (element F) are arranged so as to face the inclined surfaces 13b and 13c. The differential detection of the element E and the element F makes it possible to detect a magnetic field in the Z-axis direction perpendicular to the substrate and the X-axis direction in the horizontal direction of the substrate. Further, if the magnetoresistive effect element 1g (element G) in the Y-axis direction is formed on the substrate horizontal plane, a triaxial magnetic field detection element for detecting a magnetic field in the triaxial direction can be configured.

  More specifically, as shown in FIGS. 12A and 12B, inclined surfaces 13b and 13c having an inclination angle of θ with respect to a parallel surface (bottom surface) parallel to the main surface 13a of the substrate 13 are provided. Forming grooves. The method of forming the groove is not particularly limited, but it is possible to use an ion milling method in which the substrate is inclined or a method in which the (111) plane is formed by etching a (100) oriented silicon substrate with a potassium hydroxide (KOH) solution. It is. In this case, it is possible to form a highly accurate inclined surface with an inclination angle θ of 54.74 degrees. When an inclined surface is formed by the ion milling method, an error of about 1 degree occurs, but there is an advantage that an arbitrary inclination angle θ can be obtained. There are no restrictions on the width and length of the groove, and the shape of the groove may have a bottom surface that is horizontal to the substrate surface depending on the relationship between the width and depth of the groove and the angle θ.

  FIGS. 12A and 12B show a case where a horizontal portion is provided on the bottom surface and the length of the groove is very long with respect to the depth. Consider the substrate 13 whose grooves extend in the Y-axis direction. The magnetoresistive element 1 is formed on each of the inclined surfaces 13b and 13c and the main surface 13a of the groove. The manufacturing method of each magnetoresistive effect element 1e, 1f, 1g is the same as that of the first embodiment. The element E formed on the inclined surface 13b of the groove and the element F formed on the inclined surface 13c of the groove have the antiferromagnetic layer 8 of the Ir—Mn film and correspond to the element B of the first embodiment. To do. The element G formed on the main surface 13a of the substrate 13 has the antiferromagnetic layer 8 of the Pt—Mn film and corresponds to the element A of the first embodiment.

  After the elements E, F, and G are formed, heat treatment is performed in a magnetic field. In the heat treatment in the magnetic field, the heat treatment is performed at 300 degrees while applying the magnetic field in the Y-axis direction, and the magnetic field of the fixed layer 9 is aligned in the Y-axis direction for all of the elements E, F, and G. Thereafter, by performing heat treatment while applying a magnetic field in the X-axis direction at 260 degrees, both the elements E and F align the magnetization directions in the X-axis direction. At this time, since the elements E and F have the effect of antiferromagnetic junction, the magnetization is aligned in the film surface direction of each element, so that the magnetization is actually directed in the He and Hf directions in the figure. Become. In the element G, heat treatment at a temperature equal to or lower than the blocking temperature at the joint surface between the antiferromagnetic layer 8 and the pinned layer 9 is performed, so that the magnetization direction of the pinned layer 9 is maintained in the Y-axis direction and becomes the Hg direction. As a result, the element E detects the combined magnetic field of the X direction and the −Z direction, and the element F detects the combined magnetic field of the X direction and the Z direction.

FIG. 13 is a diagram for explaining magnetic field detection on the XZ plane in the triaxial magnetic field detection element of FIG. Here, the XZ plane is a plane including the X axis and the Z axis. As shown in FIG. 13A, the externally applied magnetic field Hex is considered by dividing it into Hex-x that is an X-axis component and Hex-z that is a Z-axis component. The magnetic field He in the direction parallel to the magnetization direction He of the pinned layer 9 detected by the element E becomes a combined magnetic field in the inclined plane directions of Hex-x and Hex-z as shown in FIG. 7)
He = Hex−x × cos θ−Hex−z × sin θ (7)

Similarly, the magnetic field Hf in the direction parallel to the magnetization direction Hf of the pinned layer 9 detected by the element F becomes a combined magnetic field in the directions of the inclined surfaces of Hex-x and Hex-z as shown in FIG. , Can be expressed by equation (8).
H−f = Hex−x × cos θ + Hex−z × sin θ (8)

From the above formula (7) and formula (8), Hex-x and Hex-z can be expressed by formula (9) and formula (10), respectively.
Hex−x = (H−e + H−f) / (2 × cos θ) (9)
Hex−y = (H−f−H−e) / (2 × sin θ) (10)

  As can be seen from the equations (9) and (10), the output voltages of the element E and the element F are detected differentially and proportional processing is performed, whereby the Z-axis direction perpendicular to the substrate and the horizontal direction X An axial magnetic field can be detected. Furthermore, in addition to the elements E and F, the magnetic field in the Y-axis direction detected by the element G can be combined to detect the magnetic field in the three-axis direction.

  Here, the case where the elements E and F are formed on the inclined surfaces 13b and 13c is shown, but two elements are formed on the main surface 13a and the bottom surface of the substrate 13, and one element is formed on the inclined surface 13b. It may be formed.

  As described above, in the magnetic field detector according to the second embodiment, the three magnetoresistive effect elements 1 are arranged on the same substrate in an inclined plane and a plane, and the three magnetoresistive effect elements are fixed to the antiferromagnetic layer. The magnetic field detector for detecting the magnetic field in the three-axis direction is made compact by creating two types with different blocking temperatures at the interface between the layers and by configuring the magnetization directions of the pinned layers of the magnetoresistive effect elements 1 to be different. Thus, a magnetic field detector capable of detecting a magnetic field in the three-axis direction with excellent mass productivity can be obtained. Further, by configuring as described above, the characteristic curve of the magnetic field / output voltage of each axis can be individually optimized.

  In addition, the magnetic field detector for detecting the three-axis direction in the second embodiment by arranging the elements for detecting the magnetic field components of the three axes on the same substrate close to each other, the magnetic field detector for uniaxial direction Compared to a case where a magnetic field detector that detects three axial directions is configured by combining magnetic field detectors to be detected, elements for detecting the magnetic field component of each axis can be arranged closer to each other. Therefore, the magnetic field detection target volume (the volume including each magnetoresistive effect element 1) is reduced, so that the detection error can be reduced and the magnetic field distribution can be detected in detail.

  Further, the magnetic field detector in the second embodiment can detect current, detect the position, and detect rotation by detecting the magnetic field in the same manner as in the first embodiment. The present invention can also be applied to an electric circuit including the magnetic field detector according to the second embodiment.

Embodiment 3 FIG.
FIG. 14 is a diagram schematically showing an overall configuration of a rotation angle detection device according to Embodiment 3 of the present invention. FIG. 14A shows a side cross-sectional view, and FIG. 14B shows a cross-sectional view taken along the line LL in FIG. 14A.

  The rotation angle detection device includes a magnetic field detection unit 23 placed on the support 20. The magnetic field detection unit 23 includes a biaxial magnetic field detection element. The support 20 has a hill-shaped protrusion at the center, and the magnetic field detector 23 is placed on the hill-shaped protrusion. A hollow rotating body 21 is arranged so as to face the support body 20 and include a hill-shaped protrusion therein. As illustrated in FIG. 14B, the rotating body 21 has a circular planar shape. A permanent magnet 22 is disposed on the inner wall of the rotating body 21 so as to face the outer peripheral portion of the hill-like protrusion of the support 20. The permanent magnet 22 is made of, for example, a samarium-cobalt alloy. In addition, the support body 20 arrange | positioned facing the rotary body 21 has a square shape which consists of a square part and a circular part as an example.

  The magnetic field detection unit 23 is connected to the DC power supply 2 and the voltmeter 3 via wirings 24 a, 24 b and 24 c installed in the support 20. The magnetic field detector 23, the DC power source 2 and the voltmeter 3 constitute a magnetic field detector. The magnetic field detector 23 is fixedly placed on the hill-like protrusion of the support 20 at a position shifted from the rotation center of the rotator 21. As the permanent magnet 22 rotates, the strength and direction of the magnetic field incident on the magnetic field detector 23 change.

  The biaxial magnetic field detection element in the magnetic field detection unit 23 is arranged so that the film surface of the internal free layer 11 and the rotation surface of the rotating body 21 are parallel to each other. That is, the external magnetic field Hex generated by the permanent magnet 22 is incident in a direction parallel to the film surface of the free layer 11 of the biaxial magnetic field detection element.

  The rotating body 21 has a rotating shaft coupled to a drive unit to be detected, and the drive unit rotates the rotating body 21 according to the movement of the detection target object.

  In the configuration of the rotation angle detection device shown in FIG. 14, the external magnetic field Hex from the permanent magnet 22 changes according to the rotation angle of the rotating body 21, and the free layer 11 of the biaxial magnetic field detection element in the magnetic field detection unit 23. The magnetization direction changes according to the direction and intensity of the external magnetic field Hex. Therefore, the magnetic field detection unit 23 extracts the resistance value of the magnetoresistive effect element that detects the magnetic field of each axis (X axis, Y axis) of the biaxial magnetic field detection element in the form of a change in voltage, etc. The angle of the magnetic field Hex with respect to the X axis of the biaxial magnetic field detection element can be calculated by Expression (6). Thereby, the rotation angle of the rotator 21 can be detected.

  The rotation of the rotator 21 can correspond to a monitor amount such as a moving amount of a moving object in accordance with a use application, and position detection and rotation amount detection can be performed. Therefore, the structure of the drive mechanism of the rotating body 21 is appropriately determined according to the application.

  As described above, the rotation angle detection apparatus according to the third embodiment is a small-sized device in which the elements for detecting the magnetic field components of the two axes on the same substrate are arranged close to each other, and detects the magnetic field distribution in detail. Since the magnetic field detector having the two-axis direction magnetic field detecting element capable of realizing the above-described structure is provided, the size can be reduced, the magnetic field detection range can be widened, and an accurate rotation angle can be detected.

  Moreover, since the magnetic field detector having the biaxial magnetic field detecting element capable of detecting the magnetic field distribution in detail is provided, it is not necessary to increase the magnetic field strength of the permanent magnet 22. Therefore, it is possible to reduce the leakage magnetic field leaking from the rotation angle detection device in the third embodiment. Thereby, it can be used also for a precision control device in which the influence of the leakage magnetic field becomes a problem.

  In addition, although the example which shifted the magnetic field detection part 23 from the rotating shaft of the rotary body 21 was demonstrated, it is not restricted to this example. Further, the triaxial magnetic field detection element shown in the second embodiment may be used. When using a triaxial magnetic field detection element, the magnetic field component in the rotational axis direction can be detected even if the triaxial magnetic field detection element is arranged at a position away from the vicinity of the rotating surface around which the permanent magnet 22 rotates. High-sensitivity magnetic field detection can be performed without causing a decrease. Thereby, the freedom degree of the arrangement position of a magnetic field detector can be raised. In addition, a magnetic field detector in which the magnetic field detector 23, the DC power source 2, and the voltmeter 3 are incorporated may be placed on the support 20.

The first to third embodiments shown here are merely examples, and the present invention is not limited to these. The lower electrode layer 6 and the upper electrode layer 12 use Ta films, but may be metal films, and are not limited to Ta films such as Cu, Ru, Al, Pt films, etc. Also good. The underlayer 7 uses a Ni—Fe film, but may be a Ta film or a Ru film like the lower electrode layer 6 and is not limited to a Ni—Fe film as long as it is a metal film. The antiferromagnetic layer 8 may be Ni—Mn, Ni—O, or Fe—Mn. The fixed layer 9 and the free layer 11 need to be ferromagnetic, but a metal containing any one of Co, Ni, and Fe as a main component, such as a Co—Ni alloy, Co—Fe—Ni, and Fe—Ni alloy, And alloys such as NiMnSb and Co ₂ MnGe. You may have the laminated structure by these films | membranes.

The tunnel insulating layer 10 is not limited to Al ₂ O _3, and may be an oxide such as Ta ₂ O ₅ , SiO ₂ , MgO, nitride, or fluoride. Further, the tunnel insulating layer 10 may be subjected to an oxidation treatment by plasma oxidation, natural oxidation, ozone, or the like after forming an Al film, for example. Furthermore, the formation of the tunnel insulating layer 10 is not limited to the oxidation of the metal film, but may be nitridation or fluorination. Also in this case, similarly to oxidation, it is possible to form a tunnel insulating layer by using radicals, plasma, and reactive gas.

  The wirings 4 and 5 are not limited to the Al film but may be other low resistance metal species such as a Cu film.

  Each metal film has been shown to be formed by DC magnetron sputtering, but may be formed by, for example, molecular beam epitaxy (MBE), various sputtering, chemical vapor deposition (CVD), or vapor deposition.

  The formation of the element shape can also be obtained by photolithography and reactive ion etching. Alternatively, pattern formation may be performed by electron beam lithography or a focused ion beam.

  Also, in the magnetic field detection methods shown in the first to third embodiments, a method for reading a voltage change when a constant DC current is applied is described here. However, an AC power source may be used, and a constant voltage may be used. It may be current detection.

It is a figure which shows schematic structure of the magnetic field detector in Embodiment 1 of this invention. It is a figure which shows the electrical equivalent circuit of the magnetic field detector shown in FIG. It is a figure which shows the cross-section in the magnetoresistive effect element shown in FIG. FIG. 3 is an element arrangement view of the biaxial magnetic field detection element in the first embodiment viewed from above the substrate surface. It is a figure which shows the cross-section of the biaxial direction magnetic field detection element cut | disconnected by the KK plane of FIG. It is a figure which shows the manufacturing process of FIG. FIG. 4 is a diagram showing the magnetic field strength dependence of the output voltage of the magnetoresistive element in the first embodiment. 2 is a diagram showing an electrical equivalent circuit of a magnetic field detector that detects a magnetic field in two axial directions in Embodiment 1. FIG. It is a figure which shows the magnetic field which injects into the biaxial direction magnetic field detection element of FIG. FIG. 6 is a diagram showing a cross-sectional structure of another biaxial magnetic field detection element in the first embodiment. It is a figure which shows the electrical equivalent circuit of the magnetic field detector in Embodiment 2 of this invention. 6 is a diagram illustrating a triaxial magnetic field detection element in a second embodiment. FIG. It is a figure explaining the magnetic field detection of the XZ plane in the magnetic field detection element of FIG. It is a figure which shows schematic structure of the angle detection apparatus in Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Magnetoresistance effect element, 8 Antiferromagnetic layer, 9 Fixed layer, 10 Tunnel insulating layer, 11 Free layer, 13 Substrate, 13a Main surface, 13b Inclined surface, 13c Inclined surface, 21 Rotating body, 22 Permanent magnet

Claims (6)

In a magnetic field detector formed with a first magnetoresistive element and a second magnetoresistive element formed on a substrate,
The first magnetoresistive element includes a first antiferromagnetic layer, a first pinned layer whose magnetization direction is fixed by the first antiferromagnetic layer, and a first magnetization layer whose magnetization direction is changed by an external magnetic field. 1 free layer, and a first tunnel insulating layer disposed between the first pinned layer and the first free layer,
The second magnetoresistive element has a second antiferromagnetic layer, a second pinned layer whose magnetization direction is fixed by the second antiferromagnetic layer, and a magnetization direction that is changed by the external magnetic field. A second free layer; a second tunnel insulating layer disposed between the second pinned layer and the second free layer;
The first blocking temperature at the bonding surface between the first antiferromagnetic layer and the first pinned layer is the second blocking temperature at the bonding surface between the second antiferromagnetic layer and the second pinned layer. Unlike
The magnetic field detector is characterized in that the magnetization direction of the first pinned layer is different from the magnetization direction of the second pinned layer. When the external magnetic field is a non-magnetic field, the magnetization direction of the first free layer is substantially perpendicular to the magnetization direction of the first pinned layer, and the magnetization direction of the second free layer is the second pinned layer. The magnetic field detector according to claim 1, wherein the magnetic field detector is substantially orthogonal to the magnetization direction of the layer. The substrate has a main surface and an inclined surface inclined with respect to the main surface;
A third magnetoresistance effect element is formed on the inclined surface;
The third magnetoresistance effect element has a third antiferromagnetic layer, a third pinned layer whose magnetization direction is fixed by the third antiferromagnetic layer, and a magnetization direction that is changed by the external magnetic field. A third tunnel insulating layer disposed between the third free layer and the third pinned layer and the third free layer, and the magnetization direction of the third pinned layer is the main surface; Arranged on the inclined surface to intersect
A third blocking temperature at the interface between the third antiferromagnetic layer and the third pinned layer is equal to the first blocking temperature or the second blocking temperature;
3. The magnetic field detector according to claim 1, wherein the magnetization directions of the first to third pinned layers are different from each other. The substrate has a main surface, a first inclined surface that is inclined with respect to the main surface, and a second inclined surface that is opposed to the first inclined surface and is inclined with respect to the main surface. ,
A third magnetoresistive element is formed on the first inclined surface;
The third magnetoresistance effect element has a third antiferromagnetic layer, a third pinned layer whose magnetization direction is fixed by the third antiferromagnetic layer, and a magnetization direction that is changed by the external magnetic field. A third tunnel insulating layer disposed between the third free layer and the third pinned layer and the third free layer, and the magnetization direction of the third pinned layer is the main surface; Arranged on the first inclined surface so as to intersect
The first magnetoresistive element is disposed on the second inclined surface so that the magnetization direction of the first pinned layer intersects the main surface;
A third blocking temperature at the interface between the third antiferromagnetic layer and the third pinned layer is equal to the first blocking temperature;
3. The magnetic field detector according to claim 1, wherein the magnetization directions of the first to third pinned layers are different from each other. 5. The magnetoresistive element according to claim 1, wherein the magnetoresistive element has a longitudinal direction and a short direction in a planar shape, and the magnetization direction of the pinned layer is the short direction. The magnetic field detector described in 1. A rotating body and a magnet disposed on the rotating body and rotating about the axis of the rotating body;
6. A rotation angle detection device, wherein the magnetic field detector according to claim 1 detects a magnetic field of the magnet.

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