JP2016001118A - Current detection device, magnetic field detection device, and methods thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current detection device, etc., in which the saturation and further the hysteresis of magnetic field responsiveness in a magnetoresistance effect element are improved and reproducibility in resistance-magnetism characteristic is improved.SOLUTION: Provided is a current detection device comprising a long and narrow magnetoresistance effect element in which a fixed layer whose magnetization direction is fixed and a free layer whose magnetization direction changes due to an external magnetic field are laminated, and a conductor extending to the vicinity of the magnetoresistance effect element, the current detection device detecting a current flowing in the conductor in accordance with the resistance value of the magnetoresistance effect element that changes due to the current induced magnetic field of the current flowing in the conductor. The magnetoresistance effect element is disposed at a position where it overlaps the conductor in whole or part as viewed from the lamination direction of the magnetoresistance effect element. The direction of the center line along a direction in which the conductor current flows differs from the direction of the center line along the longitudinal direction of the magnetoresistance effect element.

Description

  The present invention relates to a current detection device, a magnetic field detection device, and the like, and particularly to a current detection device, a magnetic field detection device, and the like using a tunnel magnetoresistance effect or a giant magnetoresistance effect having a spin valve structure.

  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. Etc., application to magnetic field detection devices is underway.

  The magnetoresistance (MR) effect is a phenomenon in which electric resistance changes depending on the magnetization direction of a magnetic material that changes with a magnetic field, and is used in a magnetic field detection device, a magnetic head, and 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 The resistance changes depending on the scattering probability, and the TMR element uses these characteristics because the magnitude of the tunnel current flowing through the insulating layer in the direction perpendicular to the film surface changes. 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 effect element having a spin valve structure can suppress a magnetic interaction between ferromagnetic layers via a metal layer or an insulating layer, and is 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 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 resistance of the element 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 set to 0 and a high-output magnetic field detection device is formed (for example, see Patent Document 1 below).

  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.

  By using the magnetic field detection method described above, it is possible to detect current in a conductor that is electrically insulated from the magnetoresistive effect element. At this time, a magnetic field induced by the current and proportional to the current is detected by the magnetoresistive element. In particular, a magnetoresistive element with a spin valve structure is suitable for detecting the magnetic field strength in the direction along the fixed layer magnetization, so that the magnetic field direction is always constant (if the conductor direction and the arrangement of the magnetoresistive element are fixed). Suitable for current detection.

  In the magnetoresistive effect element used in the magnetic field detection device, when the magnetization of the ferromagnetic material rotates, a hysteresis indicating a path depending on the previous magnetization state is generated, so that reproducibility of detection accuracy can be obtained. First, it becomes a detection error. As a countermeasure, it is necessary to control the magnetic anisotropy in the free layer. For this purpose and the purpose of adjusting the offset in the magnetic field response, a method of applying a bias magnetic field to the free layer from the outside of the element is used. As a method for applying the bias magnetic field, for example, there is a method using a permanent magnet as disclosed in Patent Document 2 below.

JP 2008-243920 A JP 2013-47610 A

  As described above, the TMR element with a spin valve structure has a high sensitivity to a magnetic field by exhibiting a large resistance change with respect to a small magnetic field, but the magnetization of the free layer is applied to the magnetic field. When the direction matches (saturates), the resistance becomes a constant value, and a large magnetic field beyond that cannot be detected, which limits the operation range.

  Further, when hysteresis occurs in the magnetization of the TMR element free layer, there is a problem in that the reproducibility in TMR element magnetic field detection is lowered and a detection error occurs.

  As a countermeasure for these problems, there is a method of applying a bias magnetic field to the free layer of the TMR element. However, the conventional method of using a permanent magnet as a bias magnetic field application method complicates the magnetic field and current detection and the manufacturing process of the device and occupies a certain area for installing the permanent magnet. To do. That is, there arises a problem that it is difficult to increase costs and to integrate elements. As a method different from the above, a method in which a bias magnetic field is applied by a magnetic field induced by current can be considered. In this case, however, the number of processes increases due to the formation of additional wiring, and the consumption for generating a current occurs. There is a problem of increasing electric power.

  The present invention has been made in order to solve the above-described problems. A current detection device and the like in which saturation of magnetic field responsiveness in a magnetoresistive effect element and further improvement in hysteresis and improved reproducibility in resistance-magnetic characteristics are provided. The purpose is to provide.

  The present invention includes an elongated magnetoresistive effect element in which a fixed layer whose magnetization direction is fixed and a free layer whose magnetization direction is changed by an external magnetic field, and a conductor extending in the vicinity of the magnetoresistive effect element, A current detecting device for detecting a current flowing through the conductor according to a resistance value of the magnetoresistive element that changes due to a current-induced magnetic field of the current flowing through the conductor, as viewed from the stacking direction in the magnetoresistive element, The magnetoresistive effect element is arranged at a position where the conductor and a part or all of the conductor overlap, and the direction of the center line along the direction in which the current of the conductor flows is the center along the longitudinal direction of the magnetoresistive effect element The current detecting device is characterized by being different from the direction of the line.

  According to the present invention, it is possible to provide a current detection device or the like in which saturation of magnetic field response in the magnetoresistive effect element and further improvement of hysteresis are improved and reproducibility in resistance-magnetic characteristics is improved.

It is the permeation | transmission perspective view which showed the positional relationship of the magnetoresistive effect element of the electric current detection apparatus by this invention and a magnetic detection apparatus, and the conductor which the electric current used as a measuring object applies. It is a figure which shows the structural example in case the detection apparatus of FIG. 1 functions as a current detection apparatus. It is a figure which shows distribution of the magnetic field which load current makes around a conductor. FIG. 2 is a sectional view taken along a dashed line a in FIG. 1. It is the top view seen from the upper surface which shows arrangement | positioning of the TMR element by Embodiment 1 of this invention, and the conductor through which the electric current used as a measuring object flows. It is a figure which shows the magnetization direction of the free layer of the TMR element of this Embodiment 1, and a fixed layer. It is a figure which shows the comparison of the change of the resistance of a TMR element with respect to the change of an electric current when an electric current is sent through a conductor. It is a figure for demonstrating the magnetic field which the electric current sent through a conductor induces. It is the top view seen from the upper surface which shows the positional relationship of the TMR element and conductor of the electric current detection apparatus by Embodiment 2 of this invention. It is a figure which shows the example which connected the several TMR element in Embodiment 2 of this invention in series. It is a figure which shows another example which connected the some TMR element in Embodiment 2 of this invention in series. It is the top view seen from the upper surface which shows the positional relationship of the TMR element and conductor of the electric current detection apparatus by Embodiment 3 of this invention. It is a figure which shows the magnetization direction of the free layer of a TMR element in Embodiment 4 of this invention, and a fixed layer. It is a figure which shows a mode that a part of magnetization of a free layer is reversed 180 degree | times. It is a figure which shows the mode after applying a fixed magnetic field to the A direction of FIG. 14, and aligning the magnetization direction of the free layer in the non-magnetic field. It is the typical top view which showed the structure of the electric current detection apparatus by Embodiment 5 of this invention. It is the typical top view which showed the structure of the electric current detection apparatus by Embodiment 6 of this invention. It is the typical top view which showed the structure of the electric current detection apparatus by Embodiment 7 of this invention. It is the typical top view which showed the structure of the electric current detection apparatus by Embodiment 8 of this invention. It is the typical top view which showed the structure of the magnetic field detection apparatus by Embodiment 9 of this invention. It is a flowchart which shows a series of procedures for performing the measurement of the external magnetic field in Embodiment 9 of this invention. It is the typical top view which showed the structure of the magnetic field detection apparatus by Embodiment 10 of this invention. It is a figure which shows the structure of the circuit element in Embodiment 10 of this invention. It is the typical top view which showed the structure of the magnetic field detection apparatus by Embodiment 11 of this invention. It is sectional drawing along the broken line X of FIG.

  In the current detection device and the magnetic detection device according to the present invention, the conductor through which the current to be detected crosses in the direction different from the longitudinal direction of the TMR element which is a magnetoresistive effect element, thereby generating a magnetic field generated by the current flowing through the conductor. A bias magnetic field can be applied in the longitudinal direction of the TMR element by applying it in both the longitudinal direction and the short direction of the TMR element. As a result, saturation of the magnetic field response of the TMR element can be suppressed, and operation in a wide magnetic field region is possible. In addition to this, the hysteresis of the TMR element is improved by the bias magnetic field and the reproducibility in the resistance-magnetic characteristics is improved, so that the current or magnetic field can be measured with high accuracy. At this time, there is no additional power consumption, an occupied area, or an increase in the number of processes.

  Hereinafter, a current detection device and the like according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
FIG. 1 is a transparent perspective view showing a positional relationship between a TMR element 1 which is a magnetoresistive effect element and a conductor 2 to which a current to be measured is applied, in the current detection apparatus and the magnetic detection apparatus according to the present invention. The upper electrode 3a and the upper surface of the TMR element 1, and the lower electrode 3b and the lower surface of the TMR element 1 are electrically connected, and the upper electrode 3a and the lower electrode 3b connect the TMR element 1 to a power source, ground or reference potential surface, and It is connected to wiring (not shown) for connecting to the voltmeter.

  FIG. 2 shows a configuration example when the detection device of FIG. 1 functions as a current detection device. Detection of the resistance change of the TMR element 1 is performed by passing a constant current from the current source 20 to the TMR element 1 and measuring the voltage at that time with the voltmeter 21. A load 22 that consumes a load current (detection target current) Il to be measured is connected to the conductor 2. FIG. 3 shows the distribution of the magnetic field generated around the conductor 2 by the load current Il at this time. A broken line b indicates the center of the conductor 2 in the width direction (x-axis direction in FIG. 3). The strength of the x-axis direction component of the magnetic field H2 generated when the load current Il flows through the conductor 2 increases as it approaches the broken line b, and increases as it approaches the conductor 2.

  4 is a cross-sectional view taken along the dashed line a in FIG. The TMR element 1 here has a spin valve structure, and an antiferromagnetic film 1aa, a ferromagnetic film 1bb, a nonmagnetic film 1cc, and a ferromagnetic film 1dd constituting a fixed layer are formed on the lower electrode 3b from below. A tunnel insulating layer 1ee is formed thereon, and a ferromagnetic film 1ff as a free layer is further formed thereon. The ferromagnetic film 1ff is electrically connected to the upper electrode 3a. The conductor 2 in the lower layer of the lower electrode 3b is disposed with the insulating layer 4 interposed therebetween in order to be electrically insulated from the lower electrode 3b. Each magnetic film is also called a magnetic layer.

  FIG. 5 shows a TMR element 1 according to the first embodiment and a conductor 2 through which a current to be measured flows, the TMR element 1 being a magnetoresistive effect element in the stacking direction, or the direction of the line connecting the TMR element 1 and the conductor 2. FIG. 4 is a plan view showing an arrangement when viewed from the element 1 side (hereinafter, simply viewed from the upper surface, for example). Note that the TMR element 1 usually has electrodes composed of electrode layers corresponding to the upper electrode 3a and the lower electrode 3b in FIG.

  The TMR element 1 is processed into a rounded rectangular shape when viewed from above. In each case, the long side length is l, the short side length (width) is w, and l> w. Here, a rectangle 101 connecting the sides of the TMR element 1 is assumed, and the intersection of the diagonal lines is defined as the center 0.

  FIG. 6 shows the magnetization directions of the free layer and the fixed layer of the TMR element 1 of the first embodiment. Due to the influence of shape magnetic anisotropy in the ferromagnetic material, the magnetization 10 of the free layer of the TMR element 1 is oriented in the longitudinal direction in the absence of a magnetic field. The magnetization 11 of the fixed layer is fixed in the short side direction of the shape of the TMR element 1.

  In the present embodiment, the center line c2 along the direction (longitudinal direction) in which the current of the conductor 2 flows is designed so that the center 0 of the TMR element 1 coincides. Here, when a current flows through the conductor 2, a magnetic field H2 is induced as shown in FIG. 3, and the free layer (1ff in FIG. 4) of the TMR element 1 is generated by the component of the magnetic field H2 in the x-axis direction. The magnetization 10 (see FIG. 6) receives a rotational force depending on the magnetic field strength, and tilts in the x-axis direction. At this time, since the magnetization of the fixed layer (1aa-1dd in FIG. 4) of the TMR element 1 is fixed, the magnetization direction 1fd of the free layer (ferromagnetic film 1ff) and the fixed layer via the tunnel insulating layer 1ee. The magnetization direction 1dd of the ferromagnetic film 1dd changes. As a result, the resistance of the TMR element 1 changes depending on the current of the conductor 2. A change in resistance of the TMR element 1 with respect to a change in current when a current is passed through the conductor 2 in the present invention is shown by a solid line A in FIG. When the conductor 2 and the TMR element 1 are arranged in parallel, that is, the center line c2 along the direction in which the current of the conductor 2 in FIG. 5 flows, and the center line c1 along the long side direction of the TMR element 1, The change in resistance of the TMR element 1 with respect to the change in current when the angle θ formed by

In actual use, a constant current is passed through the TMR element 1 and the voltage at the top and bottom thereof is measured to read the change in resistance of the TMR element 1. As a result, the current in the conductor 2 can be measured by the TMR element 1.
That is, for example, a constant current is supplied from the current source 20 of FIG. 2 to the TMR element 1, and the upper and lower voltages are measured by the voltmeter 21. Then, the measurement / control unit (not shown) calculates the resistance of the TMR element 1 from the current and voltage, and for example, the current of the conductor 2 and the current of the TMR element 1 as shown in FIG. -Obtain the current in the conductor 2 from the resistance characteristic table.

  When the current detection via the magnetic field is performed, the conductor 2 and the TMR element 1 are electrically insulated as shown in the cross-sectional view of FIG. Detection is possible.

  In the arrangement of the present embodiment, since the center 0 of the TMR element is at the position indicated by the broken line b in FIG. 3, it is possible to detect the maximum magnetic field in the xy plane at a certain distance z from the conductor 2. Yes, efficient detection is possible.

Also here
An angle θ between the extending direction of the TMR element 1 and the conductor 2,
The length l of the TMR element 1,
The width w0 of the conductor 2,
In relation to
w0 / l = sinθ
I met the conditions. In addition, the design is performed at an angle θ that is greater than 0 degrees. θ is preferably 3 degrees or more. As described above, the magnetic field generated from the conductor 2 is maximum in the portion along the center line c2, but the range included in the width of the conductor 2 is sufficient to function as a current detection device. A simple magnetic field can be applied. In the arrangement shown here, the center line c1 in the longitudinal direction of the TMR element 1 is all included in the range of the width w0 of the conductor 2. For this reason, the magnetic field H <b> 2 generated by the detection target current Il flowing through the conductor 2 is efficiently applied to the TMR element 1. As a result, efficient detection is possible even in current detection.

  The effects of this embodiment will be described below. As described above, in the present embodiment, the angle θ formed by the extending direction of the TMR element 1 and the conductor 2 is designed to be substantially larger than 0, particularly 3 degrees or more. In addition, for example, as shown in FIG. 5, since the entire TMR element 1 is disposed so as to overlap the conductor 2 when viewed from above, the TMR element 1 can be efficiently detected. At this time, the x-direction component of the magnetic field induced by the current flowing through the conductor 2 is the magnetic field component detected by the TMR element 1.

Here, in FIG. 8, when attention is paid to the magnetic field in the x direction of the magnetic field induced by the current flowing through the conductor 2, this magnetic field component is further divided into a component 211 facing the longitudinal direction of the TMR element 1 and a component 212 facing the short direction. Shows the state when disassembled. Assuming that the component 210 directed in the x-axis direction of the magnetic field induced by the current flowing through the conductor 2 is uniform and the magnitude is H0, the longitudinal component of the TMR element 1 is H0 · sin θ. The direction is H0 · cos θ. In this case, the magnetic field Hs at which the free layer of the TMR element 1 is saturated in the magnetic field direction is approximately,
Hs = Hk + H0 · sinθ
It is expressed as Hk is an anisotropic magnetic field of the magnetization of the free layer, and represents a magnetic field that tries to stay in the longitudinal direction of the shape. In order to design θ so as not to be 0 degrees, H0 · sin θ ≠ 0. That is, the magnetic field component 210 in the x-axis direction has an effect of simultaneously acting on the longitudinal component 211 and the transverse component 212 of the TMR element 1.

Due to this effect, when the magnetic field from the conductor 2 increases, the longitudinal component 211 increases, so that it is possible to suppress magnetization saturation in the short direction. This makes it possible to detect a larger magnetic field than when θ is zero. Specifically, in the case of the conventional element arrangement, the maximum current that can be measured is the current intensity i (Hk) (see FIG. 7) that generates a magnetic field equal to Hk. Thus, it is possible to measure up to a current that generates a magnetic field larger than i (Hk) and equal to Hk + H0 · sin θ.
At this time, when θ is 3 ° or more, the longitudinal component of the TMR element 1 is 5% or more of H0, and a significant effect is obtained.

  Further, the current detecting device here is composed only of the TMR element 1 and the conductor 2 through which the current to be detected flows, and no special mechanism for improving the characteristics of the free layer of the TMR element 1 is provided.

  By the way, when the angle θ between the extending direction of the TMR element 1 and the conductor 2 is 0, the magnetization of the free layer of the TMR element 1 generates hysteresis. This is mainly due to the effect that the magnetization at the end in the long side direction relaxes along the shape in the magnetization distribution in the free layer. In order to improve this, a method of applying a DC magnetic field in the longitudinal direction of the TMR element 1 is effective (the magnetic field applied at this time is generally called a bias magnetic field).

On the other hand, when the angle between the extending direction of the TMR element 1 and the conductor 2 is not 0 as in the present invention, the longitudinal component of the magnetic field generated from the conductor 2 has a significant magnetic field in the longitudinal direction of the TMR element 1. Since it is applied, a part of the magnetic field induced by the current to be measured can be used as a bias magnetic field, and the occurrence of hysteresis can be suppressed.
According to the above embodiment, in the current detection, it is possible to obtain the effect of the bias magnetic field without providing an additional mechanism other than the TMR element 1, so that an effect of ensuring a larger measurement region than the conventional one can be obtained. At the same time, the current can be detected with high accuracy.

Embodiment 2. FIG.
FIG. 9 is a plan view seen from above showing the positional relationship between the TMR element 1 and the conductor 2 of the current detection device according to Embodiment 2 of the present invention. The configuration viewed from the cross section and other basic configurations are the same as those of the first embodiment, and only the size and positional relationship in the plane of the TMR element 1 and the conductor 2 are different.

Here, the TMR element 1 is smaller than the width w0 of the conductor 2, and the conductor 2 overlaps the entire TMR element 1 when viewed from above. As in the first embodiment, the magnetic field generated from the conductor 2 is maximum at the portion along the center line c2 and is large at the portion included in the width of the conductor 2. When it is assumed that when the conductor 2 overlaps the TMR element 1, the center line c1 in the longitudinal direction of the TMR element 1 is all included in the width range of the conductor 2, the length l of the TMR element 1, the conductor 2 The relationship between the width w0, the angle θ between the longitudinal direction of the TMR element 1 and the longitudinal direction of the conductor 2 and the shortest distance a between the center 0 of the TMR element 1 and the center line c2 of the conductor 2 is w0> l · sin θ + 2a
Meet.

  With the above configuration, for example, it is possible to improve the degree of freedom of arrangement when using a plurality of TMR elements 1 in an integrated manner while obtaining the same effect as in the first embodiment. Examples of wiring in which a plurality of TMR elements are connected in series are shown in FIGS. For example, FIG. 25 shows an example of the arrangement of the TMR element, the upper electrode, and the lower electrode for realizing the series connection of the TMR elements shown in FIG. 25A is a cross-sectional view taken along the broken line X in FIG. 10, and FIG. 25B shows the magnetization direction in the cross section of each layer of each TMR element 1. Each TMR element is connected in series by an upper electrode 191 and a lower electrode 192.

  FIG. 10 shows an example in which a plurality of TMR elements 1 satisfying the conditions of this embodiment are arranged so as to overlap the conductor 2 and all the TMR elements 1 are connected in series. The TMR element 1 basically has an upper electrode and a lower electrode (the same applies to the present invention). In FIG. 10, wirings 191 and 192 indicate electrical wiring between the TMR elements 1, and specifically, the wirings 191 and 192 extend between the adjacent TMR elements and are shared as shown in FIG. (192) and the lower electrode (191). The plurality of TMR elements 1 are electrically connected in series with their upper portions and lower portions alternately connected in order. In order to show the arrangement of the TMR element 1, the wiring connecting the lower parts of the TMR element 1 is the wiring 191, the wiring connecting the upper parts is the wiring 192, the connection point between the lower wiring and the lower part of the TMR element 1 is the white circle 194, the upper wiring A black circle 193 indicates a connection point between the TMR element and the top of the TMR element. The wiring on the lower side (back side) of the TMR element 1 is indicated by a broken line, and the connection point is indicated by a white circle. These wirings 191 and 192 are realized by a lower electrode (191) and an upper electrode (192) as shown in FIG. 25, for example. A plurality of TMR elements 1 are arranged between the resistance measuring device 190 and the ground, and the upper parts and the lower parts of the adjacent TMR elements 1 are electrically connected in turn alternately. In the wiring of FIG. 11, two series circuits of the TMR elements 1 connected in series in the same manner are connected in parallel between the resistance measuring device 190 and the ground.

  By using the series connection, it is possible to average variations in manufacturing TMR elements and reduce variations in characteristics during manufacturing. In addition, since the resistance of the entire element can be increased by connecting in series, it is possible to prevent the element from being broken down and failing when a large voltage is applied unintentionally due to static electricity or the like.

  On the other hand, FIG. 20 shows an example in which a plurality of TMR elements 1 connected in series are connected in parallel between the resistance measuring device 190 and the ground. With such a configuration, the above-described effect of averaging the resistance variation at the time of manufacturing the TMR element 1 can be obtained, and the resistance of the TMR element 1 can be adjusted.

  With the configuration of the present embodiment, the degree of freedom can be extended to the layout of the TMR element on the conductor as described above.

Embodiment 3 FIG.
FIG. 12 is a plan view seen from above showing the positional relationship between the TMR element 1 and the conductor 2 of the current detection device according to Embodiment 3 of the present invention. The configuration viewed from the cross section and other basic configurations are the same as those of the first embodiment, and only the size and positional relationship in the plane of the TMR element 1 and the conductor 2 are different.

In the present embodiment, the TMR element 1 and the conductor 2 are partially overlapped when viewed in a plan view. Although the effect is small as compared with the first and second embodiments, the same effect can be obtained because the TMR element 1 and the conductor 2 partially overlap each other. Here, it is a condition for the TMR element 1 and the conductor 2 to partially overlap.
2a <l · sinθ and l · sinθ> w0
It has a configuration that meets the requirements.

  The sensitivity of the TMR element 1 decreases as the influence of the demagnetizing field increases with the miniaturization of the element. On the other hand, when the current flowing through the conductor 2 is constant, the strength of the magnetic field induced by the current increases as the width w0 of the conductor 2 decreases. With the configuration of this embodiment, sensitivity can be recovered by concentrating a large magnetic field on a part of the TMR element.

Embodiment 4 FIG.
The basic configuration and operation of the current detection device according to the fourth embodiment of the present invention are the same as those of the first embodiment. FIG. 13 shows the magnetization directions of the free layer and the fixed layer of the TMR element 1 according to the fourth embodiment, and shows the magnetization direction 10 of the free layer and the magnetization direction 11 of the fixed layer.

  As shown in FIG. 6 of the first embodiment, when the magnetization 11 of the fixed layer is fixed in the short side direction of the TMR element 1, the shape of the fixed layer 11 is affected by the demagnetizing field due to the shape, for example, when the temperature becomes high. It may be inclined in the longitudinal direction. The magnetization 11 of the fixed layer shown in FIG. 13 is fixed in advance so as to be in the longitudinal direction of the shape, and the fixation is more stable as compared with the case of fixing in the short direction. In this case, for example, even when the temperature rises and the fixation of the ferromagnetic film by the antiferromagnetic film becomes weak, the magnetization direction is maintained by the effect of shape magnetic anisotropy. The magnetization direction of the fixed layer is a desired magnetic field that can saturate the magnetization of the fixed layer at a temperature at which exchange coupling between the antiferromagnetic film and the ferromagnetic film in contact with the antiferromagnetic film disappears during the heat treatment in the manufacturing process of the TMR element 1. It can be determined by applying in the direction.

  In this configuration, a resistance change occurs when the magnetization 10 of the free layer shown in FIG. 13 is inverted by 180 °. As a countermeasure, for example, the magnetization 10 of the free layer is saturated in the upward direction on the paper before the operation. It is effective to apply a magnetic field.

  FIG. 14 shows a state in which a part of the magnetization of the free layer is inverted by 180 degrees. Arrows 220 and 221 in FIG. 14 indicate the respective magnetization directions when the magnetization of the free layer of the TMR element 1 is viewed at the level of the magnetic domain structure. In the initial state, the magnetization of the free layer of the TMR element 1 faces the longitudinal direction of the TMR element, but it is uncertain whether it faces the A direction or the B direction of the arrow 222 shown in FIG. In this state, the resistance of the TMR element 1 without a magnetic field becomes unstable, so that the magnetization direction of the free layer must be aligned before operation. For this purpose, for example, the direction can be made uniform by applying a constant magnetic field 231 in the A direction before the operation. FIG. 15 shows a state after applying a constant magnetic field 231 in the A direction and aligning the magnetization direction of the free layer without a magnetic field.

  According to the present embodiment, it is possible to stabilize the magnetization of the fixed layer and obtain the same effect as in the first embodiment. As a result, for example, it is possible to reduce the influence caused by the change in the magnetization direction of the fixed layer due to temperature and miniaturization.

Embodiment 5 FIG.
FIG. 16 is a schematic plan view showing the configuration of a current detection device according to Embodiment 5 of the present invention. In FIG. 16, in order to clearly show the positional relationship between the conductor 2 and the TMR element 1, the TMR element 1 is shown larger than the drawings in the first to third embodiments. A combination of the TMR element 1 and the conductor 2 shown in the first embodiment (61 in FIG. 6) and a combination in which the position of the conductor 2 is mirror-symmetric (62 in FIG. 6) are prepared. The one end 2a is connected. The longitudinal direction of the TMR element 1 is the same direction. The two TMR elements 1 shown here are connected in series. One TMR element is grounded and the other is connected to a power source, and detects the difference between the potential 63 and the ground potential between the TMR elements.
That is, one electrode of one TMR element 1 is grounded (GND), the other electrode is connected to one electrode of the other TMR element 1, and the other electrode of the other TMR element 1 is connected to the power supply (Vcc). The connection point between the TMR elements 1 is an output terminal (Vout). Reference numeral 15 denotes a detection target current, and 16 denotes a magnetic field induced by the current (current-induced magnetic field).

  Then, the difference between the potential (Vout) 63 between the TMR elements and the ground potential is detected. FIG. 16 shows one TMR element in each of the configuration of the combination 61 and the configuration of the combination 62. However, a plurality of TMR elements may be connected in series as long as they are the same number in each configuration, and further include a parallel connection. Also good.

  Since the arrangement of the conductors 2 is mirror-symmetric with respect to the longitudinal direction of the TMR element 1, the short direction component of the TMR element of the magnetic field induced by the current flowing through each conductor 2 is reversed. For this reason, the TMR element 1 exhibits resistance changes in opposite directions with respect to the current flowing through the conductor 2. Since each TMR element 1 constituting each has the same temperature characteristic, an error (offset) of an output when no current is applied to the conductor 2 as compared with the case where one of them has a different temperature characteristic such as a fixed resistance. Can be reduced. Further, in the present embodiment, the amount of change is twice as much as the resistance of each TMR element 1 changes in magnitude, compared to the case where one resistance is fixed. The output change for the same current flowing is doubled. As a result, a smaller current can be detected.

  According to the above configuration, it is possible to realize a current detection device that can suppress the influence of resistance variation of the TMR element due to temperature or the like and can obtain a large output signal. Further, by connecting a plurality of TMR elements, it is possible to suppress the influence of characteristic variations caused by the manufacturing process.

Embodiment 6 FIG.
FIG. 17 is a schematic plan view showing the configuration of a current detection device according to Embodiment 6 of the present invention. Here, two configurations (referred to as current detection units) shown in the fifth embodiment are connected in series (two configurations each composed of one conductor 2 and two TMR elements 1 are connected side by side). The connection point 70 is connected to the power source (Vcc). Furthermore, the middle point (the connection point between the TMR elements 1 connected in series) is connected to the voltmeter 18 and the remaining terminals are grounded (GND).

  That is, with respect to the W-shaped conductor 2 in which two mirror-symmetrical V-shaped conductors in FIG. 16 are connected in mirror symmetry, each inclined portion of the conductor 2 (the TMR element is inclined with respect to the conductor (θ ) Are arranged so that two series circuits of the two TMR elements 1 are formed between the power supply (Vcc) and the ground (GND). A voltmeter 18 is connected between the connection points of the TMR elements 1 of the two series circuits. At this time, the TMR elements of the two series circuits connected to the power supply (Vcc) side must be mirror-symmetric with respect to the arrangement of the conductors.

  In this configuration, when no current is applied to the conductor 2, the TMR elements 1 have the same resistance, so that the midpoints are equipotential to each other, so that no potential difference occurs. At this time, the voltmeter 18 connected between the middle points indicates zero. On the other hand, when a current is applied to the conductor 2, a potential difference is generated between the midpoints, so that a Wheatstone bridge is configured. When a current flows through the conductor 2, the current in the conductor 2 can be detected by measuring the voltage with the voltmeter 18.

  Each TMR element shown in FIG. 17 may be composed of a plurality of TMR elements as in the fifth embodiment.

  In the present embodiment, the output when no current is passed through the conductor 2 is 0, and a voltage change proportional to a resistance change with respect to the magnetic field induced by the current passed through the conductor is obtained as an output. The processing for calculating is unnecessary, and the peripheral circuit can be simplified. Further, since the temperature characteristics of the TMR elements that are configured are all equal, the offset can be reduced, and the influence of resistance change due to the temperature characteristics can be reduced.

Embodiment 7 FIG.
FIG. 18 is a schematic plan view showing the configuration of a current detection device according to Embodiment 7 of the present invention, and shows the configuration of a half bridge using a TMR element 17 for reference. Here, the TMR element 1 and the conductor 2 on the left side of the paper are the same as those in the first embodiment, but the reference TMR element 17 on the right side of the paper has the same longitudinal direction as the TMR element 1 on the left side, and the conductor 2 is arrange | positioned in the direction orthogonal to the longitudinal direction. The magnetization direction of the fixed layer is the same. As in the fifth embodiment, the respective conductors are connected, and the connection between the two TMR elements is the same as in the fifth embodiment shown in FIG.

  Here, with respect to the magnetization of the free layer of the reference TMR element 17, the magnetization direction 10a of the free layer of the reference TMR element 17 faces the longitudinal direction of the shape due to the shape anisotropy in a state where the magnetic field 16 is not applied. The magnetization direction 11a of the fixed layer is oriented in a direction perpendicular to this.

  When the current 15 to be detected flows through the conductor 2, the induced magnetic field 16 is applied to the reference TMR element 17 in a direction parallel to the longitudinal direction. Therefore, the resistance value of the reference TMR element 17 shows a constant value regardless of the presence or absence of the detection target current 15 flowing through the conductor 2.

  Each TMR element shown in FIG. 18 may be composed of a plurality of TMR elements as in the fifth embodiment.

  By forming a half bridge similar to that of the fifth embodiment by using these TMR elements, an output corresponding to the detection target current 15 can be output based on the resistance value of the reference TMR element 17. As a result, it is possible to suppress fluctuations in output with respect to resistance fluctuations such as temperature.

Embodiment 8 FIG.
FIG. 19 is a schematic plan view showing the configuration of a current detection device according to Embodiment 8 of the present invention, and shows the configuration of a full bridge using reference TMR elements 17a and 17b. Here, two half bridges (referred to as current detection units) shown in the seventh embodiment are connected in series (one conductor 2 and one TMR element (1a, 1b) and one reference). Two TMR elements (17b, 17a) are connected side by side), and the connection point 70 is connected to a power source (Vcc). Further, the midpoint of each half bridge (the connection point of the TMR elements (1a, 1b) and the reference TMR elements (17b, 17a)) is connected to the voltmeter 18, and the remaining terminals are grounded (GND). And constitutes a Wheatstone bridge.

  That is, each of the TMR elements (1a, 1b) disposed on the inclined portion of the conductor 2 (so that the TMR element has an inclination (θ) with respect to the conductor) and the conductor 2 are orthogonal to the longitudinal direction. Two series circuits composed of one reference TMR element (17b, 17a) arranged in a direction are connected between a power supply (Vcc) and a ground (GND), and reference is made to the TMR element 1 of the two series circuits. A voltmeter 18 is connected between the connection points of the TMR element 17 for use. Here, the TMR element connected to Vcc is connected to either one of the TMR elements (1a, 1b) and one of the TMR elements (17b, 17a) of the above two series circuits. It must be.

  When a current flows through the conductor 2, the current in the conductor 2 can be detected by measuring the voltage with the voltmeter 18.

  Each TMR element shown in FIG. 19 may be composed of a plurality of TMR elements as in the fifth embodiment.

  According to the present embodiment, in addition to the effects shown in the seventh embodiment, the output when no current is applied to the conductor 2 is 0, and the potential difference generated by applying the current is proportional to the current. The absolute value of the potential difference thus obtained can be handled as a measured value. Further, since a double output signal can be obtained with respect to the seventh embodiment, a smaller current can be detected.

Embodiment 9 FIG.
FIG. 20 is a schematic plan view showing the configuration of a magnetic field detection device according to Embodiment 9 of the present invention. Magnetic field detection is performed using the current detection device according to the present invention. Here, the external magnetic field H20 applied from the x-axis direction shown in FIG. 20 is detected. This external magnetic field H20 must be parallel to the x-direction component 16 of the magnetic field produced by the current flowing through the conductor 2.

  Here, first, the resistance of the TMR element 1 is measured to obtain a value in the state where the external magnetic field H20 to be measured does not exist (the resistance of the TMR element 1 when there is no external magnetic field H20 is defined as R0). Also, FIG. 20 compares the measuring instrument for measuring the resistance of the TMR element at this time with the obtained resistance and the value of R0, and according to the result, the current flowing through the conductor 2 to the current source 20a is compared. A measurement / control unit 102 including a control unit and a storage unit (both not shown) for supporting the increase / decrease is shown.

  Next, the resistance of the TMR element 1 is measured with the external magnetic field H20 to be measured applied (the measured value at this time is R1, and the absolute value of the difference between R0 and R1 is ΔR, where ΔR is , The absolute value of the resistance change due to the magnetoresistive effect generated in the TMR element 1 by applying the external magnetic field H20, and a current for supplying a direct current to the conductor 2 from the measurement / control unit 102 to the current source 20a. The supply command 103 is output, and the current supply command 103 also designates a current value to be supplied.As a result, the current-induced magnetic field 16 generated by the direct current supplied to the conductor 2 is applied to the external magnetic field H20. The resistance of the TMR element 1 in a state where a direct current is supplied to the conductor 2 is defined as ΔR ′.

  At this time, if ΔR> ΔR ′ (when the resistance of the TMR element 1 approaches R0), the direct current is further increased in the same direction. On the other hand, if ΔR <ΔR ′ (the resistance of the TMR element 1 moves away from R0), the current is decreased. This is repeated, and the current value when the resistance of the TMR element 1 becomes equal to the resistance (R0) when no magnetic field is applied is specified. Here, the condition for specifying the current value depends on whether ΔR ′ is smaller than a certain magnitude α. This α is a resistance change of the TMR element 1 that changes due to a current change at the lower limit of the control resolution of the current flowing through the conductor 2, or an error due to noise existing in the space, or a quantization error due to the measurement resolution of the measurement / control unit 102. By setting any one of the largest values, it is possible to measure the external magnetic field H20 with the smallest error.

  As a result, the specified current is regarded as a current that causes the magnetic field 16 induced by the current to generate a magnetic field having the same magnitude in the opposite direction to the external magnetic field H20 to be measured in the portion of the TMR element 1. be able to. In addition, since the strength of the magnetic field generated by the current is proportional to the current, the magnitude of the external magnetic field H20 can be specified by multiplying the specified current by a certain coefficient.

It has been shown that by using the method described so far, it is possible to detect an external magnetic field using the magnetic field detection device according to the present invention. In order to measure with high accuracy and to measure a magnetic field in a wide intensity range in such a method, the magnetic characteristics A (current-resistance characteristics) of the TMR element 1 in the case of applying the present invention shown in FIG. Such magnetic characteristics that are difficult to saturate and have no hysteresis are required, and the present invention makes it possible to realize a magnetic field detection device that achieves the above effects.
FIG. 21 is a flowchart showing a series of procedures for measuring an external magnetic field according to the present invention described so far. This is performed in the measurement / control unit 102. In brief,
The resistance R0 of the TMR element 1 is measured with the external magnetic field H20 applied, and then the resistance R1 of the TMR element 1 is measured with the external magnetic field H20 applied to determine the absolute value ΔR of the difference between R0 and R1 ( Step S1),
For example, the current in the A → B direction of the conductor 2 in FIG. 20 is increased or the current in the B → A direction is decreased (step S2).
The resistance R2 of the TMR element 1 in a state where a direct current is supplied to the conductor 2 is measured, and the absolute value ΔR ′ of the difference between R2 and R0 is obtained (step S3),
If ΔR> ΔR ′ (when the resistance of the TMR element 1 approaches R0), steps S1 to S4 are repeated to increase the direct current in the same direction, and ΔR ′ <α (α: a predetermined value). (Steps S4, S5)
The supply current I is converted into a magnetic field and output (step S11),
If ΔR <ΔR ′ (the resistance of the TMR element 1 moves away from R0) in step S4, the absolute value ΔR of the difference between R0 and R1 is obtained (step S6).
For example, the current in the B → A direction of the conductor 2 in FIG. 20 is increased or the current in the A → B direction is decreased (step S7).
An absolute value ΔR ′ of the difference between R2 and R0 is obtained (step S8),
If ΔR> ΔR ′ (when the resistance of the TMR element 1 approaches R0), steps S6 to S9 are repeated to increase the direct current in the same direction, and when ΔR ′ <α (steps S9, S10). ),
The supply current I is converted into a magnetic field and output (step S11),
If ΔR <ΔR ′ (the resistance of the TMR element 1 moves away from R0) in step S9, the process returns to step S1 to repeat the operation.
The current I supplied to the conductor 2 first flows in the direction from the end A to the end B of the conductor 2 in the flowchart of FIG. 21, but this order may be reversed.

Embodiment 10 FIG.
FIG. 22 is a schematic plan view showing the configuration of the magnetic field detection device according to the tenth embodiment of the present invention. The magnetic field detection device shown in the ninth embodiment is replaced with the bridge shown in the seventh embodiment. It is a figure at the time of comprising. In the tenth embodiment, the reference TMR element 17 disposed at a position orthogonal to the conductor 2 and the TMR element 1 intersecting at an angle θ with the conductor 2 are connected in series, and both ends thereof are connected to the power source (Vcc). Each is connected to an equipotential surface or a ground (GND) surface. When the external magnetic field H20 to be measured does not exist, the resistances of these two TMR elements 1 and 17 have the same value, so the potential at the connection point 251 between the TMR element 1 and the reference TMR element 17 is Vcc / 2.

  When the external magnetic field H20 is applied, the resistance of the TMR element 1 and the resistance of the reference TMR element 17 become unequal (the absolute value of the difference between the voltage at the connection point 251 and Vcc / 2 is defined as ΔV). Therefore, the potential at the connection point 251 is not Vcc / 2. Here, when a current is supplied to the conductor 2, the resistance of the TMR element 1 is changed by the magnetic field 16 induced by the current. As a result, since the magnitude relationship between the resistances of the reference TMR element 17 and the TMR element 1 changes, ΔV also changes (ΔV after this change is defined as ΔV ′). Similar to ΔR ′ in the ninth embodiment, the current applied to the conductor 2 is controlled by the voltmeter / control unit 252 and the current source 20a so as to minimize the ΔV ′. It is possible to specify a current for inducing a magnetic field that becomes a resistance when no external magnetic field is applied.

  At this time, it is possible to improve accuracy by covering the reference TMR element 17 with a magnetic shield 254 or the like so as not to be affected by the external magnetic field H20. FIG. 23 shows the configuration of the circuit elements of this embodiment. The resistor 261 in FIG. 23 is the reference TMR element 17, and the variable resistor 260 is the TMR element 1. The potential at these connection points is compared with Vcc / 2 using a comparator 262.

  Since the temperature characteristics of the TMR element 1 and the reference TMR element 17 are the same in this embodiment, the resistance when the external magnetic field H20 is not applied at each temperature can be obtained from the reference TMR element 17. It is possible to accurately specify the current that becomes a resistance when the TMR element 1 at each temperature does not apply the external magnetic field H20 without being affected by an error due to temperature characteristics.

  Note that the current source 20a in FIG. 22 may be configured to change the direction of the current flowing through the conductor 2 as in the current source 20a in FIG.

Embodiment 11 FIG.
FIG. 24 is a schematic plan view showing the configuration of the magnetic field detection device according to the eleventh embodiment of the present invention, and is a diagram in the case where a Wheatstone bridge is configured using the magnetic field detection device described in the tenth embodiment. is there. The configurations of the tenth embodiment are connected in series, a power supply (Vcc) is applied to the connection point 271, and the other ends are grounded (GND). The potential between the middle points of the TMR elements (1a, 1b) and the reference TMR elements (17c, 17d) is measured by a voltmeter / control unit 252 and connected so that the current source 20a can be controlled according to the result. Has been.

  Here, the resistances of the TMR elements 1a and 1b change with respect to the external magnetic field H20, but the reference TMR elements 17c and 17d always show resistance when the external magnetic field H20 is not applied. Here, when the external magnetic field H20 is not applied, since the TMR elements 1a and 1b and the reference TMR elements 17c and 17d all have the same resistance, the output measured by the voltmeter / control unit 252 is zero. On the other hand, if the external magnetic field H20 exists, the resistances of the TMR elements 1a and 1b and the reference TMR elements 17c and 17d become unequal, and a voltage is generated in the voltmeter / control unit 252. The voltage at this time is ΔV. Here, when a current is supplied from the current source 20a to the conductor 2, the resistance of the TMR elements 1a and 1b also changes and ΔV changes due to the magnetic field induced by the current (the voltage after the change is assumed to be ΔV ′). By comparing the voltages ΔV and ΔV ′ at this time and identifying the current that minimizes ΔV, the current that induces the magnetic field corresponding to the external magnetic field H20 can be identified.

  In this embodiment, since ΔV can be obtained as an absolute value, it is possible to amplify the obtained ΔV and determine the current to be applied to the conductor 2, thereby simplifying the circuit components. Is possible.

  Note that the current source 20a in FIG. 24 may be configured to change the direction of the current flowing through the conductor 2 as in the current source 20a in FIG.

Embodiment 12 FIG.
In each of the embodiments of the present invention, it goes without saying that the conductor 2, the upper electrode 3a, and the lower electrode 3b must be made of a conductive material. It is desirable to use a metal having a high conductivity such as aluminum, Cu, Au, or Ag as the material. As a result, the upper limit of the current that can be applied to the conductor 2 is improved, so that a larger current can be detected.

  The conductor 2 may be formed using a carbon nanotube having high conductivity, a conductive polymer, or the like as long as the material has a conductivity comparable to or exceeding the above-described substances. .

When a material such as aluminum, gold, or silver is used, the film is formed by sputtering. Cu or the like is formed by a damascene method using a plating technique and a planarization technique.
When the TMR element 1 is formed on the upper layer of the conductor 2 as shown in FIG. 4, the conductor 2 and the lower electrode 3b are formed, and then planarized by a method such as chemical mechanical polishing (CMP). Thereafter, it is desirable to form the TMR element 1.

  The present invention is not limited to the above-described embodiments, and includes all possible combinations thereof.

  1, 1a, 1b TMR element (magnetoresistance effect element), 1aa antiferromagnetic film, 1bb ferromagnetic film, 1cc nonmagnetic film, 1dd ferromagnetic film, 1ee tunnel insulating layer, 1ff ferromagnetic film, 2 conductor, 3a upper part Electrode, 3b Lower electrode, 4 Insulating layer, 17, 17a, 17b Reference TMR element (magnetoresistance effect element), 20, 21a Current source, 21 Voltmeter, 22 Load, 102 Measurement / control unit, 190 Resistance measuring device, 252 Voltmeter / control unit, 254 Magnetic shield, 262 Comparator.

Claims (11)

An elongated magnetoresistive effect element in which a fixed layer whose magnetization direction is fixed and a free layer whose magnetization direction is changed by an external magnetic field, and a conductor extending in the vicinity of the magnetoresistive effect element, In accordance with the resistance value of the magnetoresistive effect element that changes due to the current-induced magnetic field of the current that flows in the current detection device,
When viewed from the stacking direction of the magnetoresistive effect element, the magnetoresistive effect element is disposed at a position where the conductor and part or all of the conductor overlap, and the direction of the center line along the direction in which the current of the conductor flows is A current detection device characterized by being different from a direction of a center line along a longitudinal direction of the magnetoresistive effect element.   When viewed from the stacking direction of the magnetoresistive effect element, the center line of the conductor and the center of the magnetoresistive effect element overlap, the width w0 of the conductor and the longitudinal length l of the magnetoresistive effect element, The current detection device according to claim 1, wherein an angle θ between the center line of the magnetoresistive element and the center line of the conductor is w0 / l = sin θ.   The current detection device according to claim 1, wherein the magnetization direction of the fixed layer of the magnetoresistive effect element is a direction orthogonal to a longitudinal direction of the magnetoresistive effect element.   The current detection device according to claim 1, wherein a magnetization direction of the fixed layer of the magnetoresistive effect element is parallel to a longitudinal direction of the magnetoresistive effect element.   A distance a between the center line of the conductor and the center of the magnetoresistive effect element, a width w0 of the conductor, a length l in the longitudinal direction of the magnetoresistive effect element, as viewed from the stacking direction in the magnetoresistive effect element, 2. The current detection device according to claim 1, wherein an angle θ between the center line of the magnetoresistive effect element and the center line of the conductor is such that w0> l · sin θ + 2a.   A distance a between the center line of the conductor and the center of the magnetoresistive effect element, a width w0 of the conductor, a length l in the longitudinal direction of the magnetoresistive effect element, as viewed from the stacking direction in the magnetoresistive effect element, 2. The current detection device according to claim 1, wherein an angle θ between the center line of the magnetoresistive effect element and the center line of the conductor is 2a <l · sin θ and l · sin θ> w 0. An even number of magnetoresistive elements arranged in parallel in the longitudinal direction and electrically connected in series are provided, and half of the magnetoresistive elements are centered at a first angle. Intersecting with the other half of the magnetoresistive elements intersecting the conductors whose centerlines intersect at a second angle different from the first angle;
When a voltage is applied to the magnetoresistive effect elements connected in series, a current flowing through the conductor is detected from a potential at a connection point between the half of the magnetoresistive effect elements and the remaining half of the magnetoresistive effect elements. The current detection device according to claim 1, further comprising a control unit that performs the operation. Two current detection units including the even number of the magnetoresistive effect elements according to claim 7 and the conductor are connected in series,
When a voltage is applied to a connection point between the current detection units, a current flowing through the conductor from a potential difference between the connection points between the half of the magnetoresistive effect elements included in each of the current detection units and the remaining half. A current detection device having a control unit for detection.   The current detection device according to claim 1, wherein an output indicating a change in resistance value of the magnetoresistive effect element is detected, and at the same time, a current source is applied in a direction to cancel the external magnetic field applied to the conductor. The current is changed from the current value to the conductor to supply current, and the output indicating the resistance change of the magnetoresistive element matches the output when the external magnetic field does not exist according to the current value supplied to the conductor. A magnetic field detection apparatus including a control unit that detects an external magnetic field. A current-induced magnetic field of a current flowing in a conductor extending in the vicinity of the magnetoresistive effect element of an elongate magnetoresistive effect element in which a fixed layer whose magnetization direction is fixed and a free layer whose magnetization direction is changed by an external magnetic field are laminated A current detection method for detecting a current flowing through the conductor in accordance with a resistance value that varies according to:
When viewed from the stacking direction of the magnetoresistive effect element, the magnetoresistive effect element is positioned so that the conductor and a part or all of the conductor overlap, and the direction of the center line along the direction in which the current of the conductor flows is the magnetoresistive effect. A current detection method of arranging differently from the direction of the center line along the longitudinal direction of the element.   11. The current detection method according to claim 10, wherein an output indicating a change in resistance value of the magnetoresistive effect element is detected, and at the same time, a current value is supplied to the conductor in a direction to cancel the external magnetic field applied to the conductor. A magnetic field detection method for detecting the external magnetic field according to a current value supplied to the conductor when an output indicating a change in resistance value of the magnetoresistive effect element coincides with an output when the external magnetic field does not exist.

Images