JP5924695B2 - Magnetic field detection device, current detection device, semiconductor integrated circuit, and magnetic field detection method - Google Patents

Description

  The present invention relates to a magnetic field detection device, a current detection device, a semiconductor integrated circuit, and a magnetic field detection method, and more particularly to a magnetic field detection device, a current detection device, and a semiconductor integrated circuit that perform magnetic field detection by a giant magnetoresistance effect or a tunnel magnetoresistance effect. And a magnetic field detection method.

  In recent years, as a magnetoresistive effect element, a TMR element having a tunneling magnetoresistance (TMR) effect capable of obtaining a larger resistance change rate than a conventional giant magnetoresistance (GMR) effect has been developed. Applications to memory and magnetic heads are underway.

  The magnetoresistance (MR) effect is a phenomenon in which electric resistance changes by applying a magnetic field to a magnetic material, and is used in a magnetic field detection device, a magnetic head, or the like. In the GMR element, a laminated structure composed of a ferromagnetic layer / metal layer / ferromagnetic layer is used, and in the TMR element, a laminated structure composed of a ferromagnetic layer / insulating layer / ferromagnetic layer is used. In these elements, by setting the spins of the two ferromagnetic layers to be parallel (0 °) or antiparallel (180 °) to each other by an external magnetic field, in the GMR element, electrons at the ferromagnetic / metal layer interface Utilizing the fact that the resistance varies depending on the scattering probability, the TMR element utilizes the fact that the magnitude of the tunnel current flowing through the insulating layer in the direction perpendicular to the film surface varies. In the GMR element and the TMR element, it is possible to detect the relative magnetization directions of the two ferromagnetic layers by detecting a resistance change.

  In these magnetoresistive elements, one ferromagnetic layer is exchange-coupled with an antiferromagnetic layer to fix the magnetization of the ferromagnetic layer to a so-called pinned layer, and the magnetization of the other ferromagnetic layer with an external magnetic field. A so-called spin-valve type structure is known, which is a free layer that can be easily inverted.

  A magnetoresistive element having a spin valve structure can suppress a magnetic interaction between ferromagnetic layers through a metal layer or an insulating layer, and can be used as a highly sensitive magnetic field detection device. . When a magnetic field is applied to the spin valve magnetoresistive element from the outside, the magnetization of the pinned layer is ideally completely fixed, so that only the magnetization of the free layer rotates according to the externally applied magnetic field. As a result, the relative angle of magnetization of the two ferromagnetic layers changes, and the element resistance changes due to the magnetoresistive effect. This change in resistance value is detected as a change in voltage with a constant current flowing through the element, for example. This voltage change is read out as a signal that changes in accordance with the applied magnetic field, so that highly sensitive magnetic field detection is possible.

  Furthermore, instead of detecting a resistance change in a single magnetoresistive effect element, a Wheatstone bridge circuit is formed using four magnetoresistive effect elements, and elements whose magnetization directions of the pinned layer are reversed are combined. Thus, a technique has been proposed in which the output in the absence of a magnetic field is 0, and a high-power magnetic field detection device is formed (see, for example, Patent Document 1).

  Even in a half-bridge circuit in which two magnetoresistive elements whose magnetization directions of the pinned layer are opposite to each other are connected in series, the output signal is determined by the resistance ratio of the two magnetoresistive elements. It is possible to suppress the influence of resistance fluctuation caused by the manufacturing process.

  However, in order to realize the above-described bridge circuit technology, it is necessary to form magnetoresistive elements having different magnetization directions of the pinned layer on the same substrate. In this formation process, it is necessary to apply magnetic fields having different directions to each fixed layer during the heat treatment. More specifically, it is necessary to heat the pinned layer at a temperature higher than the blocking temperature and to apply a local magnetic field at which the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer in contact therewith is not observed. In general, heat treatment in a magnetic field that applies a uniform magnetic field to the substrate is used, but in this case, formation is impossible. When the above-mentioned bridge is formed using a heat treatment in a magnetic field with a general uniform magnetic field, it is necessary to form a plurality of elements on the same substrate, then cut the substrate and place it in a direction rotated by 180 ° There is a problem in that a process for arranging the cut substrates and making electrical connections is required. In addition, there is a problem that the substrate area of the entire detection device increases.

  For example, another conventional technique described in Patent Document 2 proposes a technique that uses a plurality of magnetoresistive elements having the same magnetization direction of the pinned layer and different magnetization easy axis directions of the free layer. In this technique, a reference element having the same magnetization direction and simultaneously formed on the same substrate as the detection element is used. This indicates that the minimum resistance or maximum resistance of the magnetoresistive effect element for detecting a magnetic field is obtained as a constant resistance, and it is possible to form a Wheatstone bridge or a half bridge without complicated processes. It is. Since it is possible to form the detecting element and the reference element on the same substrate in the same process, it is possible to suppress the influence of the resistance variation caused by the manufacturing process and temperature in the magnetoresistive effect element. is there.

Japanese Patent No. 3017061 Japanese Patent No. 4513804

  As described above, for example, as described in Patent Document 1, in a bridge circuit using an element in which the magnetization direction of the pinned layer is reversed, the output signal is large, but formation on the same substrate is difficult. After forming a plurality of elements on the substrate, it is necessary to cut the substrate and install it in a direction rotated by 180 °, which requires a process for arranging the cut substrate and making electrical connection. there were. In addition, there is a problem that the substrate area of the entire detection device increases.

  Further, for example, as described in Patent Document 2, if a technique using a plurality of magnetoresistive effect elements having the same magnetization direction of the pinned layer and different easy axis directions of the free layer is used, the manufacturing process is complicated. It is possible to form the aforementioned Wheatstone bridge or half bridge on the same substrate by the same process. Thus, if the bridge circuit technique is used, it is possible to suppress the influence of the resistance fluctuation caused by the manufacturing process and temperature of the magnetoresistive effect element, and to obtain an output signal having a large resistance. However, the magnetoresistive effect element for reference used as a constant resistance maintains its magnetization direction due to the shape magnetic anisotropy of the free layer, and the magnetization direction may be tilted or reversed by an external magnetic field. There was a problem that changed. Thereby, even when a reference magnetoresistive element is used, it is difficult to stably secure a resistance value at the zero point of the magnetoresistive element for detecting a magnetic field. For this reason, there has been a problem that a detection error occurs due to a change in the resistance value of the magnetoresistive effect element for reference, and the magnitude of the detection magnetic field is restricted.

  The present invention has been made to solve such a problem, and stabilizes the resistance value of a reference magnetoresistive effect element used as a constant resistance, thereby facilitating control of zero point output in a magnetic field detection device for detection. It is an object of the present invention to obtain a magnetic field detection device, a current detection device, a semiconductor integrated circuit, and a magnetic field detection method that can suppress detection errors, show a stable output signal, and are easy to manufacture. It is said.

The present invention is a magnetic field detection device that outputs an output signal corresponding to an external magnetic field, and includes two or more magnetoresistive effect elements for detecting a magnetic field provided on a substrate and two or more provided on the substrate. The reference magnetoresistive effect element, and a bias magnetic field applying wiring for simultaneously applying a magnetic field in the direction of the easy axis of the free layer of the two or more reference magnetoresistive effect elements, The magnetoresistive effect element for detecting a magnetic field includes a fixed layer composed of an antiferromagnetic layer and a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and a magnetic layer whose magnetization direction is changed by the external magnetic field. The two or more reference magnetoresistive elements have a structure in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. Antiparallel to And those states are include those connected in series, the direction of the magnetic field in which the bias magnetic field applying interconnection is applied, among the two or more reference magnetoresistive element, the magnetization direction of the pinned layer The magnetic field for the free layer in a state where the magnetization direction of the free layer is parallel is parallel to the magnetization direction of the pinned layer, and the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are antiparallel. The magnetic field for the state in the state is anti-parallel to the magnetization direction of the pinned layer, and the magnetoresistive element for detecting a magnetic field has a magnetic field in which the magnetization direction of the pinned layer is different from the magnetization direction of the free layer in the absence of a magnetic field. It is a detection device.

The present invention is a magnetic field detection device that outputs an output signal corresponding to an external magnetic field, and includes two or more magnetoresistive effect elements for detecting a magnetic field provided on a substrate and two or more provided on the substrate. The reference magnetoresistive effect element, and a bias magnetic field applying wiring for simultaneously applying a magnetic field in the direction of the easy axis of the free layer of the two or more reference magnetoresistive effect elements, The magnetoresistive effect element for detecting a magnetic field includes a fixed layer composed of an antiferromagnetic layer and a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and a magnetic layer whose magnetization direction is changed by the external magnetic field. The two or more reference magnetoresistive elements have a structure in which the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. Antiparallel to And those states are include those connected in series, the direction of the magnetic field in which the bias magnetic field applying interconnection is applied, among the two or more reference magnetoresistive element, the magnetization direction of the pinned layer The magnetic field for the free layer in a state where the magnetization direction of the free layer is parallel is parallel to the magnetization direction of the pinned layer, and the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are antiparallel. The magnetic field for the state in the state is anti-parallel to the magnetization direction of the pinned layer, and the magnetoresistive element for detecting a magnetic field has a magnetic field in which the magnetization direction of the pinned layer is different from the magnetization direction of the free layer in the absence of a magnetic field. Since it is a detection device, the manufacturing process is easy, the resistance value of the reference magnetoresistive effect element used as a constant resistance is stabilized, and control of the zero point output in the detection magnetic field detection device is facilitated. To suppress detection error, it is possible to exhibit stable output signal.

It is a figure explaining the magnetization direction of the free layer and fixed layer of a magnetoresistive effect element for a detection. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a detection. It is a figure explaining the magnetization direction of the free layer and pinned layer of a magnetoresistive effect element for a reference. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a reference. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 1 of this invention. It is a schematic diagram of the cross-sectional structure of the magnetoresistive effect element of the magnetic field detection apparatus of Embodiment 1 of this invention. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a reference in Embodiment 1 of this invention. It is a figure explaining the external magnetic field dependence of the output signal of the magnetic field detection apparatus in Embodiment 1 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 2 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 3 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 4 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus in the modification of Embodiment 4 of this invention. It is a top view for demonstrating the structure of the electric current detection apparatus of Embodiment 5 of this invention. It is a top view for demonstrating the application example of the electric current detection apparatus of Embodiment 5 of this invention. It is a top view for demonstrating the structure of the electric current detection apparatus in the modification of Embodiment 5 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus of Embodiment 6 of this invention. It is a figure explaining the external magnetic field dependence of the element resistance of the magnetoresistive effect element for a detection in Embodiment 6 of this invention. It is a flowchart which shows the magnetic field detection operation in Embodiment 6 of this invention. It is a flowchart which shows another magnetic field detection operation in Embodiment 6 of this invention. It is a top view for demonstrating the structure of the magnetic field detection apparatus in the modification of Embodiment 6 of this invention.

  Before describing the embodiment of the present invention, first, a specific detection operation of a magnetic field detection apparatus using a spin valve magnetoresistive effect element will be described with reference to FIG. The spin-valve magnetoresistive element 1 for detecting a magnetic field is configured by laminating a pinned layer and a free layer. Here, an ideal state is considered in which there is no interaction between the pinned layer and the free layer. . FIG. 1 is a schematic diagram showing the magnetization directions of the free layer and the pinned layer of the magnetoresistive element 1 for detecting a magnetic field. In FIG. 1, the magnetization direction 2 of the free layer of the spin-valve magnetoresistive element 1 in the absence of a magnetic field and the magnetization direction 3 of the fixed layer in the absence of a magnetic field are perpendicular to each other, and the angle formed by them is 90 °. . The magnetization direction 2 of the free layer in the absence of a magnetic field is determined by the shape of the free layer and is the longitudinal direction thereof. When an external magnetic field H is applied in the direction along the magnetization direction 3 of the pinned layer of the spin valve magnetoresistive element 1, the magnetization of the free layer changes its direction by the external magnetic field H and becomes the magnetization direction 2a. . At this time, the resistance value of the magnetoresistive effect element 1 changes linearly according to the angle θ formed by the changed magnetization direction 2a of the free layer and the magnetization direction 3 of the pinned layer.

Specifically, when the magnetization direction 3 of the pinned layer is 0 ° and the angle formed by the magnetization direction 2a of the free layer when an external magnetic field H is applied thereto is θ, the resistance of the magnetoresistive effect element 1 Is proportional to cos θ. If the free layer is a soft magnetic film having uniaxial anisotropy, and cosθ = H / H _k. That is, if a large external magnetic field H than a predetermined value H _k is applied, will magnetization direction 2a of the free layer is fixed to parallel (0 °) or antiparallel (180 °) the magnetization direction of the pinned layer, The resistance of the magnetoresistive effect element 1 does not change any more. That is, ideally, H _k is the saturation magnetic field of the free layer.

  As a result, the resistance (element resistance) R of the magnetoresistive effect element 1 is expressed by the following equation (2) when the magnetization direction 2 of the free layer and the magnetization direction 3 of the pinned layer are 90 ° in the absence of a magnetic field. 1), and changes as shown in FIG.

R = R _m + ΔR / 2 · H / H _k (where −H _k ≦ H ≦ H _k ) (1)

Here, R _m is the intermediate value between the maximum resistance value and minimum resistance values that can take the resistance R of the magnetoresistive element 1, by the resistance value of the magnetoresistive element 1 of the ideal no magnetic field in the is there. ΔR is the maximum magnetoresistance change amount of the magnetoresistive effect element 1 (that is, the difference between the maximum resistance value and the minimum resistance value). Since the resistance R of the magnetoresistive element 1 changes linearly with respect to the external magnetic field H, the magnitude of the external magnetic field H can be detected by obtaining the resistance R of the magnetoresistive element 1. The detected external magnetic field H is a directional component in the magnetization direction 3 of the pinned layer. The magnetic field region that can be detected in the magnetization direction of the pinned layer, that is, the operation region is −H _k ≦ H ≦ H _k .

Next, FIG. 3 is a schematic diagram showing the magnetization directions of the free layer and the pinned layer of the reference spin-valve magnetoresistive element 11. The reference magnetoresistive element 11 shown in FIG. 3 is arranged so that its longitudinal direction is orthogonal to the longitudinal direction of the magnetoresistive element 1 for detection shown in FIG. That is, the elements 1 and 11 are arranged on the substrate so that the longitudinal direction of the magnetoresistive element 1 for detection and the longitudinal direction of the magnetoresistive element 11 for reference are different from each other by 90 °. . The magnetization direction 3 of the pinned layer in the magnetoresistive element 11 is the same as that of the magnetoresistive element 1 for detection shown in FIG. In FIG. 3, as in FIG. 1, the magnetization direction 3 of the pinned layer in the absence of a magnetic field is set to 0 °. In FIG. 3A, the magnetization direction 2 of the free layer of the magnetoresistive effect element 11 is the same as the magnetization direction 3 of the pinned layer in the absence of a magnetic field, and both are 0 °. That is, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are in parallel. In this magnetoresistive effect element 11, when a magnetic field H is applied in the 0 ° direction, which is the same direction as the magnetization direction 3 of the pinned layer, the direction of the magnetic field coincides with the magnetization direction 3 in the absence of a magnetic field. Thus, the magnetization direction 2a of the free layer is stabilized. On the other hand, when a magnetic field is applied in the 180 ° direction, the magnetization direction is reversed to the magnetic field direction after maintaining the magnetization direction up to a certain magnetic field Hc. That is, since the magnetization direction 2a of the free layer and the magnetization direction 3 of the fixed layer under a magnetic field are stable at 0 ° and 180 °, the resistance value of the magnetoresistive element 11 has two values. This is shown in FIG. 4. Specifically, the resistance value represents R _m ± ΔR / 2. In this case, the resistance value of R _m −ΔR / 2 is stable when H ≦ + H _c , and the resistance value of R _m + ΔR / 2 is stable when H ≧ −H _c .

  On the other hand, in FIG. 3B, the magnetization direction 2 of the free layer of the spin valve magnetoresistive element 11 and the magnetization direction 3 of the pinned layer in the absence of a magnetic field are opposite, and the angle formed by them is 180 °. It is. That is, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are antiparallel (parallel and reverse). Also in this case, the resistance value of the magnetoresistive effect element 11 basically shows the dependency shown in FIG. 4 with respect to the external magnetic field.

The resistance R of the magnetoresistive effect element 11 for reference exhibits a constant resistance up to a constant magnetic field without depending on the external magnetic field. Therefore, when the area of the magnetoresistive effect element for detection is the same, The maximum resistance or the minimum resistance of the magnetoresistive element for detection can be obtained from the value of the resistance R of the magnetoresistive element 11. In the reference element shown in FIG. 3A, the magnetizations of the pinned layer and the free layer are previously in parallel, and the resistance is R _m −ΔR / 2. On the other hand, in the reference element shown in FIG. 3B, the magnetization of the pinned layer and the free layer is antiparallel in advance, and the resistance is R _m + ΔR / 2.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

Embodiment 1.
FIG. 5 is a top view showing the magnetic field detection apparatus according to Embodiment 1 of the present invention. The magnetic field detection apparatus shown here includes four detection magnetoresistance effect elements 101a, 101b, 102a, and 102b (hereinafter referred to as detection elements) and four reference magnetoresistance effect elements 111a, 111b, and 112a. 112b (hereinafter referred to as a reference element). These magnetoresistive elements each have a rounded rectangular shape with the same area and shape when viewed from above, so that the longitudinal direction differs by 90 ° between the detection element and the reference element. Has been placed. Further, the number of detection elements and the number of reference elements are both four, which is the same number.

  The detection elements 101a and 101b and 102a and 102b are connected in series by metal wirings 51 and 52, respectively. The reference elements 111a and 111b and 112a and 112b are connected in series by metal wirings 53 and 54, respectively. Further, the detection element 101 a and the reference element 111 a are connected by the metal wiring 55, the detection element 102 b and the reference element 112 b are connected by the metal wiring 56, and the detection element 102 a and the reference element 111 b are connected by the metal wiring 57. The detection element 101b and the reference element 112a are connected by a metal wiring 58. The metal wiring 55 is connected to a power source (not shown), and the metal wiring 56 is grounded. The metal wirings 57 and 58 are each connected to a signal detection circuit (not shown) provided outside. In this manner, the magnetic detection device of FIG. 5 forms a bridge circuit.

  The detection elements 101a and 101b and the detection elements 102a and 102b are arranged in parallel. The detection elements 101a and 101b and the detection elements 102a and 102b are separated by a predetermined distance. The reference elements 111a and 111b and the reference elements 112a and 112b are arranged in parallel. Further, the reference elements 111a and 111b and the reference elements 112a and 112b are separated by a predetermined distance.

In addition, a magnetic field application wiring 151 that is electrically insulated from the reference elements 111a, 111b, 112a, and 112b is disposed immediately below the reference elements 111a, 111b, 112a, and 112b. Direction or wiring direction) is arranged in a direction orthogonal to the longitudinal direction of the reference elements 111a, 111b, 112a, 112b. The magnetic field applying wiring 151 can simultaneously apply a magnetic field _Hbias to the left of the paper for the reference elements 111a and 112a and to the right of the paper for the reference elements 111b and 112b when a current flows. As shown, it is folded back into a U shape. In other words, the magnetic field application wiring 151 is composed of a single wiring folded back 180 ° in the same plane.

  The detection elements 101a, 101b, 102a, and 102b and the reference elements 111a, 111b, 112a, and 112b all have the same laminated structure, and a schematic diagram of the cross-sectional structure is shown in FIG.

  In FIG. 6, an electrode layer 62 is formed on a substrate 61, and then an antiferromagnetic layer 63 is formed. Next, the antiferromagnetic layer 63 forms a ferromagnetic layer 64 whose magnetization direction is fixed. Subsequently, a nonmagnetic layer 65 and a ferromagnetic layer 66 are formed. Further, a nonmagnetic layer 67 to be a tunnel insulating layer is formed, and a free layer 68 made of a magnetic material whose magnetization direction is changed by an external magnetic field is formed thereon. Is formed. An electrode layer 69 is formed on the free layer 68. The ferromagnetic layers 64 and 66 are magnetically antiparallel coupled via the nonmagnetic layer 65. Here, a laminated structure including the antiferromagnetic layer 63, the ferromagnetic layer 64, the nonmagnetic layer 65, and the ferromagnetic layer 66 functions as the fixed layer 70. In the following description, the magnetization of the ferromagnetic layer 66 is referred to as the magnetization of the pinned layer 70 for simplicity of description.

  In this pinned layer 70, since the two ferromagnetic layers 64 and 66 are coupled in antiparallel, the apparent magnetization of the entire pinned layer 70 can be suppressed, and the magnetic force applied to the free layer 68 can be reduced. It is possible to suppress a general influence and an influence that the fixed layer 70 receives from a magnetic field.

  Here, the configuration in which the antiferromagnetic layer 63 to the free layer 68 are sequentially stacked is shown, but the configuration is not limited to this, and conversely, the free layer 68 is at the bottom and the free layer 68 is reversed. The elements can also be configured by stacking in this order.

  The free layers 68 of the detection elements 101a, 101b, 102a, 102b and the reference elements 111a, 111b, 112a, 112b have a longitudinal direction because the shapes of these elements are rectangular, and thus have a shape magnetic anisotropy. Thus, the magnetization direction of the free layer 68 is the longitudinal direction of each of these elements. Since the magnetization direction of the pinned layer 70 is the same for the detection element and the reference element, in the four detection elements 101a, 101b, 102a, and 102b, the magnetization direction of the pinned layer 70 is free in a non-magnetic field. It is orthogonal to the magnetization direction of the layer 68 in the element plane (90 °). On the other hand, the magnetization direction of the pinned layer 70 of the four reference elements 111a, 111b, 112a, 112b is parallel (0 °) or antiparallel (180 °) to the magnetization direction of the free layer 68 in the absence of a magnetic field. It has become.

  In FIG. 5, as described above, the magnetic field application wiring 151 for applying the magnetic field to the four reference elements simultaneously is provided. The magnetic field application wiring 151 can simultaneously apply a magnetic field to each of the reference elements 111a and 112a and the reference elements 111b and 112b, but directly below the reference elements 111a and 112a, The direction of the current flowing through the magnetic field application wiring 151 immediately below the reference elements 111b and 112b is opposite. For this reason, the magnetic field applied to each element is leftward on the paper surface for the reference elements 111a and 112a and rightward on the paper surface for the reference elements 111b and 112b. That is, the magnetic field application wiring 151 has directions that are 180 ° different from each other in the easy axis direction of the free layer of the reference elements 111a and 112a and the easy axis direction of the free layer of the reference elements 111b and 112b. A magnetic field can be applied simultaneously.

By _passing a current I _bias that generates a magnetic field H _bias having a value larger than Hc shown in FIG. 4 through the magnetic field applying wiring 151, the reference elements 111a and 112a have the magnetizations of the fixed layer and the free layer antiparallel. Thus, the resistance value is R _m + ΔR / 2. The reference elements 111b and 112b are in a parallel state, and the resistance value is R _m −ΔR / 2. As shown in FIG. 4, the resistance of these reference elements to the magnetic field has hysteresis, so that the above resistance value can be maintained even after the current I _bias of the magnetic field application wiring 151 is stopped. is there. In this state, the reference device 111a and 111b, and, the reference device 112a and 112b, respectively, because they are connected in series, each of the series resistance becomes 2R _m. Similarly, for detection elements, detection elements 101a and 101b, and, the detection elements 102a and 102b, respectively, are connected in series, the resistance at the non-magnetic field becomes mutually equal resistance becomes 2R _m.

  Here, as a material constituting the ferromagnet in the free layer 68 and the pinned layer 70 of each element, the ferromagnetic layer 64 uses a Co—Fe alloy, and the ferromagnetic layer 66 uses a Co—Fe—B alloy. In the free layer 68, a Co—Fe—B alloy is used. However, the present invention is not limited to this, and any ferromagnetic film that has at least one of Co, Ni, and Fe such as Fe and Co as a main component may be used.

The nonmagnetic layer 67 that is a tunnel insulating layer is made of an MgO film. The nonmagnetic layer 67 that is a tunnel insulating layer is not limited to this, and may be Al ₂ O ₃ , HfO ₂ , Ta ₂ O ₅ , MgAl ₂ O _4, or the like, which is an oxide film of another metal, Not only oxides but also nitrides and fluorides may be used.

  The antiferromagnetic layer 63 that fixes the magnetization of the ferromagnetic layer 64 in the fixed layer 70 is made of an Ir—Mn alloy film. Note that the antiferromagnetic layer 001c is not limited to the Ir—Mn alloy film, and may be any antiferromagnetic film such as a Pt—Mn alloy, an Fe—Mn alloy, or a Ni—Mn alloy, and obtains the same effect. Is possible.

  The nonmagnetic layer 65 in the pinned layer 70 is made of a Ru film. The nonmagnetic layer 65 is not limited to the Ru film, and may be any nonmagnetic film of a transition metal mainly composed of a platinum group such as Rt, Rb, and the like, and the same effect can be obtained.

  The lower electrode layer 62 and the upper electrode layer 69 are each made of a Ta (tantalum) film. Each of the lower electrode layer 62 and the upper electrode layer 69 may be another metal such as a Ru film, but is not limited thereto. Lower electrode layer 62 and upper electrode layer 69 are connected to respective metal wirings shown in FIG. Cu (copper) is used for each metal wiring. The metal wiring may be other metal such as Al (aluminum), and is not limited to this.

  Next, a method for manufacturing the magnetoresistive effect element and the magnetic field detection device according to the first embodiment will be described.

  Referring to FIG. 6, each metal film constituting the magnetoresistive effect element is formed on substrate 61 by DC (direct current) magnetron sputtering. The substrate 61 is made of Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), glass, or the like. In addition, the board | substrate 61 is not limited to this, Other materials may be sufficient. Here, a substrate is used in which the magnetic field application wiring 151 is formed directly below the magnetoresistive effect element. Other wirings, electronic circuits such as transistors and diodes may be formed under the magnetoresistive element.

  First, a Ta film is formed on the substrate 61 as the lower electrode layer 62 using DC magnetron sputtering. After the Ta film as the lower electrode layer 62 is formed, an Ir—Mn alloy film is formed as the antiferromagnetic layer 63 in the same apparatus without being exposed to the atmosphere. Subsequently, a Co—Fe alloy film as the ferromagnetic layer 64 is formed without being exposed to the atmosphere. Next, a Ru film as the nonmagnetic layer 65 and a Co—Fe—B alloy film as the ferromagnetic layer 66 are formed. , Respectively. Subsequently, after the MgO film is formed as the nonmagnetic layer 67 using RF (high frequency) magnetron sputtering without being exposed to the atmosphere, a Co—Fe—B alloy film is formed as the ferromagnetic film of the free layer 68. Thereafter, a Ta film is formed as the upper electrode layer 69 using DC magnetron sputtering.

  When these films are formed, a magnetic field of 100 Oe is applied in the film surface direction. Thereby, magnetic anisotropy is imparted to the Ir—Mn film, the Co—Fe film, and the Co—Fe—B film constituting the fixed layer 70. The films from the lower electrode layer 62 to the upper electrode layer 69 constituting the magnetoresistive effect element 1 are all formed in the same device. The MgO film that is the nonmagnetic layer 67 may be formed by exposing to an oxidizing atmosphere containing oxygen after the Mg film is formed by DC magnetron sputtering.

  The above film may be formed by, for example, molecular beam epitaxy (MBE) method, various sputtering methods, chemical vapor deposition (CVD) method, vapor deposition method, or plating.

  Thereafter, heat treatment is performed. The purpose is to promote crystallization of the MgO film and the two Co-Fe-B films sandwiching it, and to impart magnetic anisotropy to the film of the pinned layer 70. Here, 10 kOe, which is a magnetic field for saturating the magnetizations of the Co—Fe—B film as the ferromagnetic layer 64 of the pinned layer 70 and the Co—Fe film as the ferromagnetic layer 66, is applied. The direction of the magnetic field application is the same as that during film formation of the magnetoresistive effect element, and is the short direction of the detection elements 101 and 102 and the long direction of the reference elements 111 and 112. The heat treatment temperature is 300 ° C., in which the magnetoresistive element can crystallize the Co—Fe—B film, and the exchange coupling between the Ir—Mn film and the Co—Fe film of the pinned layer is substantially eliminated. Yes. This temperature was maintained for 1 hour.

  After the heat treatment described above, the magnetizations of the ferromagnetic layers 64 and 66 of the pinned layer are directed in directions different from each other by 180 °. That is, the magnetization of the Co—Fe alloy film and the magnetization of the Co—Fe—B alloy film facing each other across the Ru film which is the nonmagnetic layer 65 are opposite to each other.

  In this embodiment, since the magnetization directions of the pinned layers of the detection element and the reference element are the same, the applied magnetic field during the heat treatment may be the same direction, and a uniform magnetic field can be applied. .

  Thereafter, a desired pattern is formed by photolithography. After a film constituting the laminated magnetoresistive effect element is formed, a desired pattern is formed by a photoresist. Thereafter, the magnetoresistive effect element is electrically and magnetically separated by reactive ion etching using a desired pattern formed of a photoresist as a mask, thereby obtaining the shape of the magnetoresistive effect element. The magnetoresistive effect element here is a rounded rectangle as described above. At this time, the longitudinal direction of the detection elements 101 and 102 is a direction orthogonal to the magnetic field application direction at the time of forming the fixing layer 70 in the laminated film, and the longitudinal direction of the reference elements 111 and 112 is the fixing layer in the laminated film. This is the same direction as the magnetic field application direction when forming 70.

  The magnetoresistive effect element for detection and the magnetoresistive effect element for reference are preferably formed simultaneously on the same substrate in the same process, and these patterns are formed using electron beam lithography, focused ion beam, or ion milling. May be.

  With the above pattern formation, in the magnetoresistive effect element, the magnetization of the Co—Fe—B film, which is a ferromagnetic layer serving as the free layer 68, is affected by the demagnetizing field depending on the shape and faces the longitudinal direction of the shape. Thereby, in the absence of a magnetic field, the magnetizations of the free layers of the detection element and the reference element are orthogonal.

  Thereafter, as shown in FIG. 5, the metal wirings 51 to 58 are connected to the magnetoresistive effect elements 101, 102, 111, and 112. As a result, the metal wiring 55 is connected to a power source (not shown), and the metal wiring 56 is grounded. The metal wires 57 and 58 are connected to a signal detection circuit that detects a voltage, respectively. Although a detailed description is omitted here, a magnetic field detection device using the magnetoresistive effect element of the present embodiment is thereby formed.

  Next, the detection operation of the magnetic field detection apparatus according to the present embodiment will be described with reference to FIG.

A predetermined constant detection current I _sense is supplied from the power supply via the metal wiring 55. At this time, since the metal wiring 56 is grounded, the current flows through the detection elements 101a and 101b and the reference element 112a to the reference element 112b, and the reference elements 111a and 111b and the detection element. There are two paths for the current flowing through the element 102a to the detecting element 102b. In no magnetic field, the resistance of these pathways are both 4R _m, current is the route _{1/2 · I sense.} Further in this case, two detection elements and two reference elements are 4R _m, since the same resistance, the potential V1 of the potential V2 and the metal wiring 58 of the metal wire 57 becomes the same potential, The output voltage represented by the potential difference (V1−V2) is 0. That is, 0 output can be obtained without a magnetic field.

  The above is a description of the case where the magnetic field is 0, but a state under a magnetic field is considered. Here, a state where no current is flowing through the magnetic field application wiring 151 will be described.

The output voltage ΔV in the bridge circuit shown in FIG. 5 is obtained by detecting V1-V2 when a constant detection current _Isense is flowed, and is expressed by the following equation (2).

ΔV = I _sense · ΔR / 2 · H / H _k (2)

That is, an output signal linear with respect to the magnetic field is obtained. By converting this output signal into a magnetic field, the magnetic field H can be detected. Since H _c ≦ H _k , the output signal V1-V2 is obtained in the region of | H | ≦ H _c . In the region of | H | ≧ H _c , the sum of the resistances of the two reference elements changes from 2R _m to 2 (R _m + ΔR) or 2 (R _m −ΔR). Output signal. Further, Once in its resistive state, unless a current magnetic field applying interconnection 151, two resistors 2R _m by reference resistance can not be obtained.

From the above, in a state where no current flows to the magnetic field application wire 151, H _c of the reference device is to provide a constraint on the operation area of the magnetic field detecting apparatus.

  Next, consider a case where a current is passed through the magnetic field application wiring 151.

The magnetic field application wiring 151 can simultaneously apply a magnetic field _Hbias to each of the reference elements 111a and 112a and the reference elements 111b and 112b. The directions of current immediately below the reference elements 111a and 112a and the reference elements 111b and 112b are opposite to each other. For this reason, the magnetic field H _bias applied to each element is leftward on the paper surface for the reference elements 111a and 112a and rightward on the paper surface for the reference elements 111b and 112b.

When the magnetic field _Hbias is generated by the current _Ibias , the resistance change with respect to the external magnetic field in which the reference elements 111a and 111b are connected in series is as shown in FIG. Referring to FIG. 7, reference elements 111 a and 111 b each have the characteristics shown in FIG. 4, but here, in addition to external magnetic field H, a constant magnetic field H _bias is applied. Thereby, in the reference element 111a, the entire hysteresis is shifted in the positive direction by H _bias . As a result, the resistance of the single element is stabilized at R _m −ΔR / 2 when H ≧ −H _c −H _bias . In the reference element 111b, the entire hysteresis is shifted in the negative direction by H _bias . As a result, the resistance of the single element is stabilized at R _m + ΔR / 2 in H ≦ H _c + H _bias . That, | H | 2 pieces in the region of ≦ _H c _{+ H bias} it is possible to obtain the 2R _m is the midpoint of the resistance of the detection elements connected in series. As described above, when there is no H _bias , the region is | H | ≧ H _c , so that the region where the reference element functions can be enlarged by 2H _bias .

FIG. 8 shows an output signal (V1-V2) when a current is passed through the magnetic field application wiring 151 with the configuration shown in FIG. Since the resistance value of the reference element indicates a resistance value that is the midpoint of the detection element, a characteristic that accurately outputs 0 in the absence of a magnetic field can be obtained. In the region | H | ≧ H _k , the external magnetic field H In contrast, a linear output signal (V1-V2) is obtained. _Here, from the fact that using the _{H bias} to be _{H c + H bias ≧ H k} , it is possible to operate without restrictions of _{H c} of the reference device.

In the above, the detection operation using a constant current has been described as an example, but a constant voltage may be used. In this case, the metal wiring 55 operates with a constant voltage _Vcc . The output signal ΔV is expressed by the following equation (3).

_{ΔV = -V cc · ΔR / 2} · H / H k / (4R m + ΔR · H / H k) (3)

  In the above-described operation at a constant voltage, even when the resistance of the magnetoresistive element changes due to the manufacturing process and temperature, the output signal is determined by the relative relationship of resistance. Since all the magnetoresistive hard effect elements here are formed in the same process, the influence of the resistance variation caused by the manufacturing process and temperature is similarly received by all the elements. For this reason, it becomes possible to suppress the influence of the resistance fluctuation resulting from a manufacturing process or temperature.

Here, an example in which the magnetic field applying wiring 151 is disposed immediately below the reference element is shown, but the direction parallel to the film surface direction of the free layer of the reference element and along the longitudinal direction (easily magnetized) As long as the magnetic field can be applied in the axial direction), the magnetic field may be disposed immediately above the reference element. In this case, the direction of the magnetic field applied to the reference element is opposite to that described above, but as a result, the same effect can be obtained. Further, if the direction of flowing the current _Ibias is reversed, the same direction as described above can be obtained.

  According to the present embodiment, by using the detection element and the reference element having the same area and the magnetization being in the parallel state and the antiparallel state, the resistance at the midpoint of the detection element is obtained. Is possible. In addition, the parallel and anti-parallel states of the reference element are formed at the same time, and the magnetic field application wiring for stabilizing each state during magnetic field detection is provided, so that stable zero-point output can be obtained and operation is possible. The magnetic field range is large, and reversal of free layer magnetization in the reference layer can be prevented.

  These can be realized without complicating the manufacturing process.

As described above, according to the first embodiment, the magnetic field detection device outputs an output signal corresponding to the external magnetic field, and includes four magnetic field detection magnetoresistive effect elements 101 provided on the substrate 61. 102, four reference magnetoresistive effect elements 111 and 112 provided on the substrate 61, and a bias magnetic field _Hbias in the easy axis direction of the free layer of the reference magnetoresistive effect elements 111 and 112 are simultaneously applied. The reference magnetoresistance effect elements 111 and 112 and the magnetic field detection magnetoresistance effect elements 101 and 102 have magnetization directions fixed by the antiferromagnetic layer 63 and the antiferromagnetic layer 63, respectively. The fixed layer 70 made of the ferromagnetic layer 64 and the free layer 68 whose magnetization direction is changed by the external magnetic field H are laminated. The reference magnetoresistive elements 111 and 112 are fixed. The magnetization direction of the adhesion layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field include those in a parallel state and those in an antiparallel state. Among the magnetoresistive effect elements 111 and 112, the magnetic field with respect to the state in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the non-magnetic field are parallel, the magnetization direction of the pinned layer 70, and the absence of the free layer 68 The magnetic field of the magnetoresistive effect elements 101 and 102 for detecting the magnetic field is 180 ° different from the magnetic field with respect to the anti-parallel direction of the magnetization direction in the magnetic field. Therefore, by applying a bias magnetic field, the resistance values of the reference magnetoresistive elements 111 and 112 used as constant resistance are stabilized, and the bias magnetic field is applied. it is possible to enlarge the amount corresponding operating magnetic field of applying _bias, it is possible to get a midpoint of the resistance value of the magnetic field detecting magnetoresistive element 101 stably, the magnetic field detecting magnetoresistive element Control of the zero point output in 101 and 102 is facilitated, a stable zero point of the magnetoresistive effect elements 101 and 102 for detecting the magnetic field is obtained, and detection errors can be suppressed. As a result, it is possible to realize a magnetic field detection device that suppresses fluctuations in the resistance value of the magnetoresistive element due to temperature and manufacturing process, is easy to manufacture, and exhibits a stable output signal.

  The reference magnetoresistive elements 111 and 112 and the magnetic field detecting magnetoresistive elements 101 and 102 are arranged in the same area, with the longitudinal directions different from each other by 90 °, and the number thereof is equal to each other. The magnetoresistive effect elements 101 and 102 and the reference magnetoresistive effect elements 111 and 112 can be formed simultaneously, and the same resistance value can be obtained.

  Further, since the magnetic field application wiring 151 is a single wiring folded back 180 ° in the same plane, it is possible to easily control the magnetization of the free layer 68 of the reference magnetoresistance effect elements 111 and 112.

Embodiment 2. FIG.
FIG. 9 is a top view showing the magnetic field detection apparatus according to Embodiment 2 of the present invention. The magnetic field detection apparatus shown here has two detection elements 101a and 101b and two reference elements 111a and 111b. These elements 101a, 101b, 111a, and 111b are the same as the elements 101a, 111a, and the like described in the first embodiment, and detailed description thereof is omitted. Also in the present embodiment, these elements 101 and 111 each have a rounded rectangular shape with the same area and shape when viewed from above, and the detection element 101 and the reference element 111. And are arranged so that their longitudinal directions differ by 90 °. The number of detection elements 101 and the number of reference elements 111 are both two, which is the same number.

  The detection elements 101 a and 101 b are connected in series by a metal wiring 51. The reference elements 111 a and 111 b are connected in series by a metal wiring 53. Further, the detection element 101 b and the reference element 111 a are connected by a metal wiring 57. The detection element 101 a is connected to a power source (not shown) by a metal wiring 55, and the reference element 111 b is grounded by a metal wiring 56. The metal wiring 57 is connected to a signal detection circuit provided outside in order to detect a potential.

As in the first embodiment, an electrically insulated magnetic field application wiring 151 is disposed immediately below the reference elements 111a and 111b, and extends in a direction perpendicular to the longitudinal direction of the reference elements 111a and 111b. Has been placed. The magnetic field applying wiring 151 is folded back 180 ° so that a magnetic field can be simultaneously applied to the reference element 111a leftward on the paper surface and to the reference 111b rightward on the paper surface when a current is applied. Has been placed. That is, the magnetic field application wiring 151 can simultaneously apply magnetic fields in directions different from each other by 180 ° in the easy axis directions of the free layers of the two reference elements 111a and 111b. The resistance values of the two reference elements 111a and 111b are maintained at R _m + ΔR / 2 and R _m −ΔR / 2, respectively, as in the first embodiment by the magnetic field of the magnetic field applying wiring 151.

  The cross-sectional structures and formation methods of the detection elements 101a and 101b and the reference elements 111a and 111b are the same as those in the first embodiment, and thus the description thereof is omitted.

  Next, the detection operation of the magnetic field detection apparatus according to the present embodiment will be described with reference to FIG.

The metal wiring 55 is kept at a constant voltage _Vcc . At this time, since the metal wiring 56 is grounded, the potential V _out in the metal wiring 57 is expressed by the following equation (4).

_{V out = V cc · 2R m} / (4R m + ΔR · H / H k) (4)

Thus, an output signal of V _cc / 2 is obtained in the absence of a magnetic field, and a voltage depending on the magnetic field H is obtained when the magnetic field H is applied from the outside.

As in the first embodiment, when a current is passed through the magnetic field application wiring 151, a reverse bias magnetic field H _bias is simultaneously applied to the reference elements 111a and 111b. As shown in FIG. 7, | H | in the region of ≦ _H c _{+ H bias,} it is possible to obtain the 2R _m is the midpoint of the series-connected two detection elements 101a, the resistance value of 101b . Also in the present embodiment, using H _{bias satisfying} H _c + H _bias ≧ H _k makes it possible to operate without being restricted by H _c of the reference element.

In this example, the magnetic field applying wiring 151 is arranged immediately below the reference elements 111a and 111b. However, the magnetic field applying wiring 151 is parallel to the film surface direction of the free layer of the reference elements 111a and 111b and is in the longitudinal direction. As long as a magnetic field can be applied to the reference elements 111a and 111b, they may be disposed immediately above. In this case, the direction of the magnetic field applied to the reference elements 11a and 111b is opposite to that described above, but the same effect can be obtained. Further, the direction in which the current I _{bias is} passed may be reversed.

  In the configuration of the present embodiment, similarly to the first embodiment, even when the resistance value of the magnetoresistive effect element changes due to the manufacturing process and temperature, the influence can be suppressed.

  According to the present embodiment, by using the detection elements 101a and 101b and the reference elements 111a and 111b having the same area and a magnetization in a parallel state and an antiparallel state, the detection elements 101a and 101b It is possible to obtain a resistance value at the midpoint of 101b. Furthermore, since the reference elements 111a and 111b are formed with the parallel state and the anti-parallel state at the same time, and are provided with the magnetic field application wiring 151 for stabilizing each state at the time of detecting the magnetic field, an operable magnetic field range is provided. And the reversal of magnetization of the free layer in the reference elements 111a and 111b can be prevented.

  These can be realized without complicating the manufacturing process.

As described above, according to the present embodiment, a magnetic field detection device that outputs an output signal corresponding to an external magnetic field, the two magnetoresistance effect elements 101 a and 101 b for magnetic field detection provided on the substrate 61. A magnetic field that simultaneously applies a bias magnetic field H _{bias in the} direction of the easy axis of the free layers of the two reference magnetoresistive elements 111a and 111b provided on the substrate 61 and the reference magnetoresistive elements 111a and 111b. The reference magnetoresistive elements 111a and 111b and the magnetic field detecting magnetoresistive elements 101a and 101b have their magnetization directions fixed by the antiferromagnetic layer 63 and the antiferromagnetic layer 63, respectively. The reference magnetoresistive element 1 has a structure in which a fixed layer 70 formed of a ferromagnetic layer 64 and a free layer 68 whose magnetization direction is changed by an external magnetic field H are laminated. 11 and 112 include those in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field are parallel and antiparallel, and the magnetic field applied by the magnetic field application wiring 151. Of the reference magnetoresistive effect elements 111a and 111b with respect to the one in which the magnetization direction of the pinned layer 70 and the magnetization direction of the free layer 68 in the absence of a magnetic field are parallel, and the magnetization direction of the pinned layer 70 The magnetic field of the free layer 68 when the magnetization direction in the non-magnetic field is antiparallel is 180 ° different from each other, and the magnetoresistive effect elements 101a and 101b for magnetic field detection have different magnetization directions of the fixed layer 70 and the free layer 68. Since the magnetization direction in the non-magnetic field is different, the resistance value of the reference magnetoresistive effect element 111 used as a constant resistance is stabilized, and the midpoint of the resistance value of the magnetoresistive effect element 101 for magnetic field detection is determined. This makes it easy to control the zero point output of the magnetoresistive effect element 101 for magnetic field detection, so that a stable zero point of the magnetoresistive effect element 101 for magnetic field detection is obtained, and detection errors are suppressed. can do. As a result, it is possible to realize a magnetic field detection device that suppresses fluctuations in the resistance value of the magnetoresistive element due to temperature and manufacturing process, is easy to manufacture, and exhibits a stable output signal.

  The reference magnetoresistive effect elements 111a and 111b and the magnetic field detecting magnetoresistive effect elements 101a and 101b are arranged in the same area, with the longitudinal directions being different from each other by 90 °, and the number thereof is equal to each other. The magnetoresistive effect elements 101a and 101b and the reference magnetoresistive effect elements 111a and 111b can be simultaneously formed, and the same resistance value can be obtained.

  Further, since the magnetic field application wiring 151 is a single wiring folded back 180 ° in the same plane, it is possible to easily control the magnetization of the free layer 68 of the reference magnetoresistance effect elements 111a and 111b.

Embodiment 3 FIG.
FIG. 10 is a top view showing a magnetic field detection apparatus according to Embodiment 3 of the present invention. The magnetic field detection device of the present embodiment has the same number of detection elements 101a, 101b, 102a, 102b and reference elements 111a, 111b, 112a, 112b in the magnetic field detection device of the first embodiment shown in FIG. They are connected in parallel.

  Specifically, in FIG. 9, the detection elements 101a and 101b are connected to the metal wiring 51 in place of the serial body composed of the detection elements 101a and 101b in the magnetic field detection apparatus of the first embodiment shown in FIG. Are connected to each other in parallel, and a serial body in which the detection elements 101a ′ and 101b ′ are connected by a metal wiring 51 ′.

  Similarly, in FIG. 9, the detection elements 102 a and 102 b are connected by the metal wiring 52 instead of the series body composed of the detection elements 102 a and 102 b in the magnetic field detection device of the first embodiment shown in FIG. 5. A bridge circuit is provided in which the series body and the series body in which the detection elements 102a ′ and 102b ′ are connected by the metal wiring 52 ′ are connected in parallel to each other.

  Similarly, in FIG. 9, the reference elements 111 a and 111 b are connected by the metal wiring 53 instead of the serial body composed of the reference elements 111 a and 111 b in the magnetic field detection device of the first embodiment shown in FIG. 5. A bridge circuit is provided in which the series body and the series body in which the reference elements 111a ′ and 111b ′ are connected by the metal wiring 53 ′ are connected in parallel to each other.

  Similarly, in FIG. 9, the reference elements 112 a and 112 b are connected by the metal wiring 54 instead of the serial body composed of the reference elements 112 a and 112 b in the magnetic field detection device of the first embodiment shown in FIG. 5. A bridge circuit is provided in which the series body and the series body in which the reference elements 112a ′ and 112b ′ are connected by the metal wiring 54 ′ are connected in parallel to each other.

  Since other operations and configurations are the same as those of the first embodiment, detailed description thereof is omitted.

  In the present embodiment, the number of detection elements 101 and 102 and the reference elements 111 and 112 are twice as many as those in the first embodiment (that is, in the first embodiment, the detection elements are all included). In contrast to the four reference elements and the four reference elements, in Embodiment 3, there are eight detection elements and eight reference elements). Even if it occurs, the characteristics can be averaged as the number of elements increases.

  Although not shown, the same effect can be obtained even when four elements are all connected in series without using a bridge circuit, or when serial connection and parallel connection are combined. These connections are also effective in adjusting the resistance. In addition, here, an example in which the present invention is applied to the configuration shown in the first embodiment has been described, but it is obvious that the present invention is effective even if applied to the configuration of the second embodiment.

  As described above, according to the present embodiment, the same effect as in the first embodiment can be obtained. Furthermore, in the present embodiment, since the number of elements for both the detection elements 101 and 102 and the reference elements 111 and 112 are doubled as compared with the first embodiment, even when characteristic variations between elements occur. Since the number of elements is large, the characteristics can be averaged.

Embodiment 4 FIG.
A fourth embodiment of the present invention will be described with reference to FIG. The configuration shown in FIG. 11 is the same as that of the first embodiment except for the magnetic field application wiring 151. In the present embodiment, as shown in FIG. 11, the magnetic field application wiring 151A extends directly below the detection elements 101a, 101b and 102a, 102b, and in that portion, the length of each detection element is long. It faces the direction orthogonal to the direction.

  That is, in the present embodiment, the magnetic field application wiring 151A is disposed in a direction that passes directly under all the elements and is orthogonal to the longitudinal direction of all the elements. Specifically, the magnetic field application wiring 151A first passes directly under the reference element 111a, and then bent by 90 °, passes directly under the detection element 101a, and then becomes a U-shape. Bent twice to 90 °, pass directly under the detection element 101b, and then bend 90 °, pass directly under the reference element 112a, and then have a U-shape twice. Bent at 90 °, passed directly under the reference element 112b, then bent at 90 °, passed directly under the detection element 102b, and then bent at 90 ° twice to form a U-shape, It passes directly under the detection element 102a, and then is bent 90 ° and passes directly under the reference element 111b.

According to this embodiment, the magnetic field H _bias applied in the longitudinal direction of the four reference elements 111 and 112 is simultaneously applied in the longitudinal direction of the four detection elements 101 and 102. That is, by the magnetic field application wiring 151A, simultaneously in the easy axis direction of the free layers of the four reference elements 111 and 112 and in the easy axis direction of the free layers of the four detection elements 101 and 102, A magnetic field _Hbias is applied. This magnetic field H _bias additionally imparts longitudinal magnetic anisotropy in the free layers of the detection elements 101 and 102. As a result, it is possible to suppress the occurrence of hysteresis. Further, the apparent anisotropic magnetic field of the free layer is expressed by the following formula (5).

H _k ′ = H _k + H _bias (5)

  That is, the sensitivity and operating magnetic field of the detection elements 101 and 102 can be controlled simultaneously while stabilizing the resistance values of the reference elements 111 and 112.

In FIG. 11, the magnetic field H _bias due to the wiring 151 </ b> A is opposite to each other, such that the detection elements 101 a and 102 a face upward and the detection elements 101 b and 102 b face downward. About this, it is not limited, The arrangement | positioning to which a magnetic field is applied to the same direction may be sufficient.

However, when the configuration in which the magnetic field H _bias by the magnetic field application wiring 151A is reversed between the detection elements 101a and 102a and the detection elements 101b and 102b as shown in FIG. It is possible to suppress the influence of the tilt of the magnetization of the pinned layer, which can be caused by a manufacturing process such as formation or heat treatment. When the external magnetic field H is applied, the free layer magnetization rotates in the opposite direction in the detection elements 101a, 102a and 101b, 102b. If the magnetization of the pinned layer is tilted relative to the assumption (direction perpendicular to the longitudinal direction), the absolute value of the angle between the free layer and the pinned layer in the absence of a magnetic field increases and decreases, respectively. Therefore, it is possible to cancel the influence.

  According to the present embodiment, it is possible to suppress the hysteresis of the free layer of the detection element while simultaneously stabilizing the resistance value of the reference element, and to control the sensitivity and the operating magnetic field. Furthermore, it is possible to suppress the influence when the magnetization of the pinned layer is tilted.

In this example, the magnetic field applying wiring 151A is arranged immediately below the reference element. However, if the magnetic field can be applied in a direction along the longitudinal direction parallel to the film surface direction of the free layer of the reference element. It may well be placed directly above the reference element. In this case, the direction of the magnetic field applied to the reference element is opposite to that described above, but as a result, the same effect can be obtained. In addition, the direction in which the current I _{bias is} passed may be reversed.

  The operation here is only different in the extending direction of the magnetic field application wiring 151A, and FIG. 11 shows an example applied to the configuration of the first embodiment. However, the present embodiment is not limited to this, and it is obvious that the present embodiment can be applied to the second embodiment and the third embodiment. FIG. 12 shows an application example to the magnetic field detection device shown in the second embodiment as an example.

  As described above, according to the present embodiment, the same effects as those of the first to third embodiments can be obtained, and in addition, in this embodiment, the magnetic field application wirings 151A and 151B are provided with a reference magnetoresistance. Simultaneously with the effect elements 111 and 112, a bias magnetic field is applied to the magnetic field detection magnetoresistive effect elements 101 and 102, so that the magnetization control of the free layer 68 of the reference elements 111 and 112 can be facilitated.

Embodiment 5 FIG.
FIG. 13 is a top view showing a current detection device according to Embodiment 5 of the present invention. The configuration of FIG. 13 uses a magnetic field detector having basically the same configuration as that of the first embodiment shown in FIG. 5, but in FIG. 13, the detection elements 101a and 101b and the detection elements 102a and 102b Are arranged at positions adjacent to each other. In the current detection apparatus according to the fifth embodiment of the present invention, immediately below these detection elements 101 and 102, a current I _line to be measured for detection, which is electrically insulated from these detection elements, is provided. A flowing metal wiring 152 is provided. The metal wiring 152 is arranged in a direction along the longitudinal direction of the detection elements 101 and 102.

Here, when a current I _line flows through the metal wiring 152 to be measured, an annular magnetic field is generated in a direction perpendicular to the metal wiring 152 by the action of this current. The magnitude of the magnetic field H _line is expressed by the following equation (6).

H _line = k · I _line / r (6)

In the above formula (6), k is a proportional constant, and r is the distance from the metal wiring 152 to the detection element 101 or 102. If the distance r between the detection element and the metal wiring 152 is measured, the proportionality constant k is known, so that the current I _line can be measured by measuring the magnetic field H _line .

  A magnetic field detector using a spin valve type element detects a magnetic field component along the magnetization direction of the pinned layer. For this reason, the magnetic field direction is always suitable for magnetic field detection in the same direction. The magnetic field generated by the current whose wiring direction and position are fixed is always in the same direction. For this reason, the current detection device according to the present embodiment using the magnetic field detection device shown in the first embodiment is suitable for current detection by detecting a magnetic field.

  Note that FIG. 13 shows a current detection device in which the present embodiment is applied to the configuration of the first embodiment. However, the present embodiment is not limited to this, and the operation here detects a current using a magnetic field. The present invention can be applied to all the magnetic field detection devices described in the first to fourth embodiments. FIG. 15 shows an application example of the magnetic field detection device shown in Embodiment 2 shown in FIG. 9 as an example. In FIG. 15, a metal wiring 152 to be measured is added to the configuration of FIG.

  In this embodiment, FIGS. 13 and 15 show examples in which the magnetic field application wiring 151 and the metal wiring 152 to be measured are arranged directly below the reference element and the detection element. It may be arranged immediately above the element. In this case, the direction of the magnetic field applied to the element is opposite to that described above, but the same effect can be obtained.

  Further, according to the present embodiment, it is possible to detect the current in the wiring of the semiconductor integrated circuit by using the effect described in the first embodiment. When applied to a semiconductor integrated circuit, since the distance between the detection element and the wiring 152 that is the object to be measured is determined by the interlayer insulating film, the distance between the magnetic detection element and the object to be measured can be reduced. As a result, highly sensitive current detection is possible.

  FIG. 14 shows an example of a semiconductor integrated circuit to which this is applied. In the semiconductor integrated circuit of FIG. 14, a power supply unit 202 that supplies power is connected to a memory unit 204 and an arithmetic circuit unit 205 through power supply lines 206 and 207, and is supplied with power. These power supply lines 206 and 207 are provided with a current detection device 201 configured by the magnetic field detection device described in the first to fourth embodiments. The current detection device 201 constantly detects the currents of the power supply lines 206 and 207 of the memory unit 204 and the arithmetic circuit unit 205 and feeds back the detected current value to the control circuit 203.

  According to this configuration, it is possible to realize current detection with high accuracy and high sensitivity without affecting the semiconductor integrated circuit. As a result, the power consumption of the semiconductor integrated circuit can be reduced by monitoring and feeding back the operation state of the integrated circuit depending on the environment.

  As described above, according to the present embodiment, since the current detection device using the magnetic field detection device shown in the first to fourth embodiments is obtained, the same effects as in the first to fourth embodiments can be obtained. By applying the magnetic field detection device according to the first to fourth embodiments, a stable current detection device can be realized. In addition, since the semiconductor integrated circuit including such a current detector is used, it is possible to reduce the power consumption of the semiconductor integrated circuit and also to integrate the functions of the magnetic field detection device and the current detection device. it can.

Embodiment 6 FIG.
FIG. 16 shows a top view of the magnetic field detection apparatus according to the sixth embodiment of the present invention. The configuration shown in FIG. 16 is the same as that of the first embodiment except for the magnetic field application wiring 151C. Here, the magnetic field application wiring 151 </ b> C extends not only to the reference elements 111 and 112 but also directly below the detection elements 101 and 102. In the detection elements 101 and 102, the longitudinal direction of each element is extended. A magnetic field application wiring 151 </ b> C is arranged in the direction along the line.

  The magnetic field application wiring 151C passes right under the detection elements 101b and 101a, and is then bent twice at 90 ° so as to form a U shape, and passes directly under the reference elements 111a and 112a. Thereafter, it is bent 90 ° twice so as to form a U-shape, and passes through the reference element 112b, the detection elements 102b and 102a, and the reference element 111b in that order. That is, the magnetic field application wiring 151 </ b> C is a single wiring that is folded twice at 180 ° in the same plane.

According to this embodiment, the magnetic field H _bias applied in the longitudinal direction of the reference elements 111 and 112 (in the direction of the easy axis of magnetization of the free layer of the reference element) is applied in the longitudinal direction of the detection elements 101 and 102. They are applied simultaneously in the orthogonal direction (the hard axis direction of the free layer of the detection element). At this time, the magnetic field H _bias due to the magnetic field application wiring 151 is all rightward with respect to the detection elements 101a and 102a and 101b and 102b. By this magnetic field H _bias , the magnetic field responsiveness of the detection elements 101 and 102 can be offset by the magnetic field H _bias . That is, it is possible to simultaneously change the operation region of the detection elements 101 and 102 while stabilizing the resistance values of the reference elements 111 and 112.

In a magnetoresistive effect element, due to the manufacturing process, an interaction occurs between the pinned layer magnetization and the free layer magnetization such as a leakage magnetic field generated from the magnetization of the pinned layer and magnetic exchange coupling through the tunnel insulating film. In addition, an offset may occur in the magnetic field response of the free layer. If this embodiment is used, the influence of the offset of the detection element can be corrected using the magnetic field _Hbias . This is shown in FIG. As shown in FIG. 17, the magnetic field responsiveness offset generated in the free layers of the detection elements 101 and 102 is corrected by the magnetic field H _bias , and a stable zero-point output can be obtained. The influence of the offset in the reference elements 111 and 112 can be suppressed for the same reason as the effect described in FIG. 7 of the first embodiment.

  FIG. 18 shows an operation example in the present embodiment. Here, a method of correcting the offset of the magnetic field responsiveness of the detection element using the characteristic that the reference element indicates the resistance of the midpoint of the detection element will be described.

First, in step S1, a predetermined constant current _Ibias is passed through the wiring 151C in the absence of a magnetic field, and the output signals V1-V2 are detected. Next, in step S2, it is determined whether V1-V2 is 0 or not. If V1-V2 is not 0, the current _Ibias is changed in step S6, and the processing in steps S1, S2, and S6 is repeated to obtain a current _{Ibias in} which V1-V2 is 0. If it is determined in step S2 that V1-V2 = 0, the process proceeds to step S3, and the current _Ibias is stored in a storage device in the magnetic field detection device or an external storage device. When the current I _{bias at} which V1−V2 = 0 is flowing, a magnetic field H _bias having a resistance value at the midpoint is applied to the detection element, in other words, the magnetic field response of the detection element. sexual offset H _OS is corrected. This is shown in FIG. Subsequently, the process proceeds to step S4, and the output signal V1-V2 is detected under the magnetic field in the state where the magnetic field H is applied while the current _Ibias obtained in the previous step S2 at which V1-V2 = 0 is passed through the wiring 151. To do. Next, in step S5, the detected output signal V1-V2 is converted into a magnetic field, and the magnetic field H is detected.

  Another operation example is shown in FIG. Here, a method for correcting the offset of the magnetic field response of the detection element in the operation by the magnetic balance method will be described.

First, in step S1, a predetermined constant current _Ibias is passed through the wiring 151C in the absence of a magnetic field, and the output signals V1-V2 are detected. In step S2, it is determined whether or not this value is 0. If not, in step S6, the current _Ibias is changed, the process returns to step S1 again, and the processes in steps S1, S2, and S6 are repeated, and V1- A current _{Ibias at} which V2 becomes 0 is obtained. The value of the current _Ibias thus obtained is stored in a storage device in the magnetic field detection device or an external storage device in step S3. In this state, a magnetic field H _{bias serving as} a midpoint resistance is applied to the detection element. In other words, the magnetic field responsive offset H _OS of the detection element is corrected. Up to this point, the operation is the same as that described with reference to FIG.

Thereafter, 19, followed by, in the state under a magnetic field a magnetic field is applied to H, and change the current _{I bias,} obtain current _{I bias} for the V1-V2 = 0. The current I _{bias at} which V 1 −V 2 becomes 0 under a magnetic field is a current that _neutralizes the external magnetic field and the offset of the magnetic field responsiveness of the detection element and makes the resistance of the detection element a middle point.

That is, in FIG. 19, in step S11, in the state under the magnetic field to which the magnetic field H is applied, the predetermined current I _bias is passed through the wiring 151, and the output signals V1-V2 are detected. In step S12, it is determined whether or not this value is 0. If not, in step S15, the current _Ibias is changed, the process returns to step S11 again, and the processes in steps S11, S12, and S15 are repeated, and step S13 is repeated. Thus, a current I _bias where V1−V2 becomes 0 is obtained. The current I _bias thus obtained, is compared with I _bias stored in the previous step S3, it excludes the influence of the offset of the magnetic field response of the sensing element. The external magnetic field H can be detected by converting the current value I _bias of the wiring 151 finally obtained in this way into a magnetic field.

  If the above configuration and operation are used, in addition to the effect of the operation described with reference to FIG. 18, the magnetic balance method is used. Therefore, the characteristics of the detection element need only stably indicate the zero point and are not necessarily linear. There is no need.

  According to the present embodiment, it is possible to stably obtain the zero point of the magnetic field detection device, and it is possible to stably suppress the influence of the element resistance change due to the temperature and the manufacturing process and the offset of the magnetic field response. An operation magnetic field detection device can be realized.

In this example, the magnetic field application wiring 151C is arranged immediately below the reference elements 111 and 112. However, the magnetic field application wiring 151C is parallel to the film surface direction of the free layer of the reference elements 111 and 112 and extends along the longitudinal direction. The magnetic field may be applied in the direction, and may be disposed immediately above the reference elements 111 and 112. In this case, the direction of the magnetic field applied to the reference elements 111 and 112 is opposite to that described above, but the same effect can be obtained as a result. The direction in which the current _Ibias flows may be reversed.

Since the operation here is only different in the extending direction of the magnetic field application wiring 151C, it is possible to apply all the magnetic field detection devices described in the first to third embodiments in a modified manner. FIG. 20 shows, as an example, a modification in which the present embodiment is applied to the magnetic field detection apparatus according to the second embodiment shown in FIG. In FIG. 20, the magnetic field application wiring 151 passes directly under the detection elements 101a and 101b and the reference elements 111a and 111b in this order. In this case, in the operation described with reference to the flowcharts of FIGS. 18 and 19, the same effect can be obtained by _changing I _{bias where} V 1 −V 2 is 0 to I _bias where V _out is 1/2 · V _cc. can get.

  As described above, according to the present embodiment, the same effects as those of the first to third embodiments can be obtained. Further, in the present embodiment, the magnetic field application wiring 151 </ b> C is a reference magnetoresistive element. Since the bias magnetic field is applied to the magnetic field detecting magnetoresistive elements 101 and 102 simultaneously with the magnetic field detecting elements 111 and 112, the magnetization control of the free layer 68 of the reference elements 111 and 112 can be facilitated.

  In the first to sixth embodiments, the magnetic field detection device, the current detection device using the magnetic field detection device, and the semiconductor integrated circuit have been described. However, the present invention is not limited thereto, and the object to be measured generates a magnetic field. Any detection device that emits light can be widely applied to other similar devices.

  In addition, although it is preferable to use a tunnel magnetoresistive effect element as the magnetoresistive effect element, the present invention is not limited to this, and other magnetoresistive effect elements such as a giant magnetoresistive effect element including a ferromagnetic layer in which one magnetization direction is fixed are used. A magnetoresistive element may be used.

  In addition, the bending angle of the magnetic field application wiring 151 has been described as 90 °. However, the present invention is not limited to this, and the point is that only one wiring folded back 180 ° within the same plane may be used. The number of bendings can be any number of times. Or you may bend in a U shape etc., without providing an angle.

  1, 101, 102 Magnetoresistive effect element for detection (detection element), 2 Magnetization direction of free layer in non-magnetic field, 2a Magnetization direction of free layer when magnetic field is applied, 3 Magnetization direction of pinned layer, 11, 111, 112 Reference magnetoresistance effect element (reference element), 51, 52, 53, 54, 55, 56, 57, 58 Metal wiring, 151 Magnetic field application wiring, 152 Metal wiring, 61 Substrate, 62 Lower electrode layer , 63 Antiferromagnetic layer, 64, 66 Ferromagnetic layer, 65 Nonmagnetic layer, 67 Tunnel insulating layer, 68 Free layer, 69 Upper electrode layer, 70 Fixed layer, 201 Current detection device.

Claims (10)

A magnetic field detection device that outputs an output signal corresponding to an external magnetic field,
Two or more magnetoresistive elements for detecting a magnetic field provided on a substrate;
Two or more reference magnetoresistive elements provided on the substrate;
A bias magnetic field applying wiring for simultaneously applying a magnetic field in the direction of the easy axis of the free layer of the two or more reference magnetoresistive effect elements;
The reference magnetoresistive effect element and the magnetic field detecting magnetoresistive effect element are each composed of a fixed layer composed of an antiferromagnetic layer and a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and the external magnetic field. And has a structure in which a free layer made of a magnetic layer whose magnetization direction changes is laminated,
Wherein two or more reference magnetoresistive element for are those wherein the magnetization direction of the pinned layer and the magnetization direction in the free field of the free layer and that of the parallel state and that of the antiparallel state is connected in series Contains
The direction of the magnetic field applied by the bias magnetic field application wiring is such that, among the two or more reference magnetoresistive elements, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. The magnetic field for the pinned layer is parallel to the magnetization direction of the pinned layer, and the magnetic field for the pinned layer and the free layer in a state where the magnetization direction of the free layer in the non-magnetic field is antiparallel is opposite to the magnetization direction of the pinned layer. Parallel ,
In the magnetoresistive effect element for detecting a magnetic field, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are different.
Magnetic field detection device. 2. The magnetic field detection device according to claim 1, wherein the magnetoresistive effect element for reference and the magnetoresistive effect element for magnetic field detection are arranged in the same area, the longitudinal directions being different from each other by 90 °, and the number thereof is the same.   3. The magnetic field detection apparatus according to claim 1, wherein the bias magnetic field application wiring is a single wiring folded back 180 ° within the same plane. 4. 4. The magnetic field detection device according to claim 1, wherein the bias magnetic field applying wiring applies the magnetic field to the magnetic field detection magnetoresistive effect element simultaneously with the reference magnetoresistive effect element. 5. . 5. The bias magnetic field application wiring simultaneously applies the magnetic field in the easy axis direction of the free layer of the reference magnetoresistive element and the easy axis direction of the free layer of the magnetic field detecting magnetoresistive element. The magnetic field detection apparatus described in 1. 5. The bias magnetic field applying wiring applies the magnetic field simultaneously in the easy axis direction of the free layer of the reference magnetoresistive element and the hard axis direction of the free layer of the magnetic field detecting magnetoresistive element. The magnetic field detection apparatus described in 1.   A current detection device using the magnetic field detection device according to claim 1.   A semiconductor integrated circuit comprising the current detector according to claim 7. A magnetic field detection method for outputting an output signal corresponding to an external magnetic field,
Two or more magnetoresistive elements for detecting a magnetic field provided on a substrate, two or more magnetoresistive elements for reference provided on the substrate, and two or more magnetoresistive elements for reference Providing a magnetic field detection device comprising a bias magnetic field application wiring for simultaneously applying a bias magnetic field in the easy axis direction of the free layer;
Detecting the output signal in a state where a predetermined bias magnetic field is applied to the reference magnetoresistive element by the bias magnetic field application wiring under a magnetic field to which the external magnetic field is applied, and
The magnetoresistive effect element for reference and the magnetoresistive effect element for magnetic field detection are each composed of an antiferromagnetic layer and a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and an external magnetic field. It has a structure in which a free layer made of a magnetic layer whose magnetization direction changes is laminated,
Wherein two or more reference magnetoresistive element for are those wherein the magnetization direction of the pinned layer and the magnetization direction in the free field of the free layer and that of the parallel state and that of the antiparallel state is connected in series Contains
The direction of the magnetic field applied by the bias magnetic field application wiring is such that, among the two or more reference magnetoresistive elements, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. The magnetic field for the pinned layer is parallel to the magnetization direction of the pinned layer, and the magnetic field for the pinned layer and the free layer in a state where the magnetization direction of the free layer in the non-magnetic field is antiparallel is opposite to the magnetization direction of the pinned layer. Parallel ,
In the magnetoresistive effect element for detecting a magnetic field, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are different.
Magnetic field detection method. A magnetic field detection method for outputting an output signal corresponding to an external magnetic field,
Two or more magnetoresistive elements for detecting a magnetic field provided on a substrate, two or more magnetoresistive elements for reference provided on the substrate, and two or more magnetoresistive elements for reference Provided is a magnetic field detection device including a bias magnetic field applying wiring that simultaneously applies a magnetic field in a direction of easy magnetization of a free layer and a direction of hard magnetization of free magnetic layers of the two or more magnetic field detecting elements. Steps,
By applying a bias current to the bias magnetic field application wiring in the absence of a magnetic field without applying the external magnetic field, the magnetization easy axis direction of the free layer of the reference magnetoresistance effect element and the magnetic resistance detection element of the magnetic field detection Detecting the output signal in a state where a magnetic field is applied in the hard axis direction of the free layer;
Determining whether the output signal is a predetermined value, and obtaining a value of the bias current at which the output signal becomes a predetermined value;
The magnetic field detecting magnetoresistive effect element and the reference magnetoresistive effect are obtained by flowing the bias current at which the output signal has a predetermined value through the bias magnetic field applying wiring under the magnetic field to which the external magnetic field is applied. Detecting the output signal with a bias magnetic field applied to the element, and
The magnetoresistive effect element for reference and the magnetoresistive effect element for magnetic field detection are each composed of an antiferromagnetic layer and a fixed layer composed of a magnetic layer whose magnetization direction is fixed by the antiferromagnetic layer, and an external magnetic field. It has a structure in which a free layer made of a magnetic layer whose magnetization direction changes is laminated,
Wherein two or more reference magnetoresistive element for are those wherein the magnetization direction of the pinned layer and the magnetization direction in the free field of the free layer and that of the parallel state and that of the antiparallel state is connected in series Contains
The direction of the magnetic field applied by the bias magnetic field application wiring is such that, among the two or more reference magnetoresistive elements, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are parallel to each other. The magnetic field for the pinned layer is parallel to the magnetization direction of the pinned layer, and the magnetic field for the pinned layer and the free layer in a state where the magnetization direction of the free layer in the non-magnetic field is antiparallel is opposite to the magnetization direction of the pinned layer. Parallel ,
In the magnetoresistive effect element for detecting a magnetic field, the magnetization direction of the pinned layer and the magnetization direction of the free layer in the absence of a magnetic field are different.
Magnetic field detection method.

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