WO2016125780A1 - Magnetic measuring device, magnetic measuring unit, magnetic measuring system, and magnetic measurement method - Google Patents

Abstract

Provided is a magnetic measuring device in which the influence of a magnetic field generated by a sense current is reduced. A magnetic measuring device (10) is provided with: magnetic resistance elements (1); upper wiring layers (2) that face magnetization free layers (7); and lower wiring layers (3) that face magnetization fixed layers (6), wherein upper inter-layer wires (4) are vertically provided between the upper wiring layers (2) and the magnetization free layers (7); and lower inter-layer wires (5) are vertically provided between the lower wiring layers (3) and the magnetization fixed layers (6).

Description

Magnetic measuring device, magnetic measuring unit, magnetic measuring system, and magnetic measuring method

The present invention relates to a magnetic measurement device, a magnetic measurement unit, a magnetic measurement system, and a magnetic measurement method for measuring a magnetic field to be measured using a magnetoresistive effect.

Currently, Hall elements that apply the Hall effect of semiconductors, magnetoresistive elements that apply the magnetoresistive effect of semiconductors and magnetic materials, fluxgate magnetometers with a conductive wire wound around a magnetic material, etc. Is widely used. In recent years, SQUID (Superducting Quantum Interference Device) using the quantum interference effect of a superconductor has been used as an ultrasensitive magnetometer.

However, the magnetic field detection sensitivity of a general semiconductor Hall element or magnetoresistive element is about 1 × 10 ⁻⁷ to 1 × 10 ⁻⁸ T (Tesla). Therefore, higher magnetic field detection sensitivity is required to measure the minute magnetic field associated with the life activity current of the human body, which has been attracting attention in recent years, and the residual magnetic force of electronic devices. Further, even in a fluxgate magnetometer with high magnetic field detection sensitivity, the magnetic field detection sensitivity is about 1 × 10 ⁻¹⁰ T, and further improvement in sensitivity is required. In addition, in the medical field, it is important to measure the spatial distribution of the strength of the magnetic field. To that end, it is necessary to arrange the elements for detecting the magnetic field in a grid pattern. However, since the fluxgate magnetometer measures a magnetic field using a coil, it is difficult to arrange elements for detecting the magnetic field in a lattice shape.

SQUID for measuring a magnetic field using the quantum interference effect of a superconductor exhibits a very high magnetic field detection sensitivity of about 1 × 10 ⁻¹⁴ T, but has a strict element structure and a FLL (Flux Locked Loop) circuit. And a complicated and large-scale drive circuit is required, and the apparatus must be cooled to a low temperature with liquid helium or the like. For this reason, the apparatus itself becomes a large-scale device and is generally difficult to use.

Therefore, there is a demand for a magnetic measuring device that has high magnetic detection sensitivity, is small, and can perform measurements easily.

For example, Patent Document 1 discloses a biomagnetic measurement apparatus that can measure biomagnetism with high accuracy using a magnetic sensor that can be used at room temperature. The biomagnetic measurement device described in Patent Document 1 includes a magnetization fixed layer in which the magnetization direction is fixed, a magnetization free layer whose magnetization direction changes under the influence of an external magnetic field, a magnetization free layer, and a magnetization fixed layer. The magnetic sensor of the living body is measured by disposing a magnetic sensor including a magnetoresistive element having an insulating layer disposed between them so as to face the living body. In the magnetoresistive element, the electric resistance value of the insulating layer changes due to the tunnel effect according to the angle difference between the magnetization direction of the magnetization fixed layer and the magnetization direction of the magnetization free layer. Therefore, biomagnetism can be measured by measuring the change in the electric resistance value.

International Publication No. 2012/032962

However, since the biomagnetism measuring device described in Patent Document 1 measures magnetism by changing the electrical resistance of the insulating layer, it is necessary to pass a current for measuring the electrical resistance (this current is referred to as a sense current). Call). Therefore, the inventors of the present application have found that the magnetic field generated by the sense current becomes noise with respect to the magnetic field to be measured. In particular, when measuring a weak magnetic field such as biomagnetism, the influence of noise of the magnetic field generated by the sense current is increased. However, in the biomagnetic measurement apparatus described in Patent Document 1, the magnetic field generated by the sense current is increased. Is not considered, and no measures are taken.

The present invention has been made in view of the above problems, and its object is to accurately reduce a weak magnetic field by reducing the influence of a magnetic field generated by a sense current in a magnetic measurement device using a magnetoresistive element. An object of the present invention is to provide a magnetic measuring device capable of measuring.

In order to solve the above problems, a magnetic measurement device according to one aspect of the present invention includes a magnetization free layer whose magnetization direction changes due to an external magnetic field, a magnetization fixed layer whose magnetization direction is fixed, and the magnetization free layer. And a magnetoresistive element in which an insulating layer disposed between the pinned layer and the magnetization fixed layer is stacked, a first wiring layer facing the magnetization free layer on the side opposite to the insulating layer side, and the pinned magnetization And a second wiring layer opposite to the insulating layer side with respect to the layer, and a magnetic current is caused by flowing a sense current from the first wiring layer or the second wiring layer to the magnetoresistive element. A first interlayer wiring is vertically provided between the first wiring layer and the magnetization free layer, and a first interlayer wiring is provided between the second wiring layer and the magnetization fixed layer. A two-layer wiring is provided vertically.

According to one aspect of the present invention, the first interlayer wiring is provided between the first wiring layer and the magnetization free layer, and the second interlayer wiring is also provided between the second wiring layer and the magnetization fixed layer. The distance from the first wiring layer and the second wiring layer to the magnetization free layer can be increased. Thereby, the influence of the magnetic field generated by the sense current is reduced, and even a weak magnetic field can be measured accurately.

(A) is a schematic diagram which shows the magnetic measuring device which concerns on Embodiment 1 of this invention, (b) is a figure which shows the flow path of the sense electric current in (a), and the magnetic field which generate | occur | produces with a sense electric current. . It is a schematic diagram which shows the magnetic measuring device which concerns on Embodiment 2 of this invention. (A) And (b) is a schematic diagram which respectively shows the magnetic field which generate | occur | produces with a sense electric current. (A) is a figure which shows distribution of the magnetic field in (a) of FIG. 3, (b) is a figure which shows distribution of the magnetic field in (b) of FIG. It is a schematic diagram which shows the magnetic measuring device which concerns on Embodiment 3 of this invention. It is a figure which shows distribution of the magnetic field generated by a sense current. It is a schematic diagram which shows the magnetic measuring device which concerns on Embodiment 4 of this invention. It is a schematic diagram which shows the magnetic measuring device which concerns on the modification of Embodiment 4 of this invention. It is a schematic diagram which shows the magnetic measuring device which concerns on the comparative example of Embodiment 4 of this invention. It is a schematic diagram which shows the magnetic measuring device which concerns on Embodiment 5 of this invention. It is a schematic diagram which shows the magnetic measuring device which concerns on the modification of Embodiment 5 of this invention. (A) And (b) is a schematic diagram which respectively shows the magnetic measuring device which concerns on the modification of Embodiment 5 of this invention. (A) is a schematic diagram which shows the magnetic measurement unit which concerns on Embodiment 6 of this invention, (b) is the elements on larger scale of the cell with which a magnetic measurement unit is provided. It is a block diagram which shows the component of the magnetic measurement system which concerns on Embodiment 6 of this invention. It is a flowchart which shows the flow of the magnetic measurement method using the magnetic measurement system which concerns on Embodiment 6 of this invention. (A) is a schematic diagram which shows the magnetic measuring apparatus used conventionally, (b) is a figure which shows the magnetic field which generate | occur | produces the sense current which flows through the magnetic measuring apparatus shown to (a), and a sense current. .

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

[Embodiment 1]
1A is a schematic diagram showing the magnetic measurement device 10 according to the present embodiment, and FIG. 1B is a diagram of the sense current I flowing through the magnetic measurement device 10 shown in FIG. The magnetic field B generated by the path and the sense current is shown.

As shown in FIG. 1A, the magnetic measuring device 10 according to this embodiment includes a magnetoresistive element 1, an upper wiring layer (first wiring layer) 2, a lower wiring layer (second wiring layer) 3, and an upper part. An interlayer wiring (first interlayer wiring) 4 and a lower interlayer wiring (second interlayer wiring) 5 are provided. 1A shows an example in which three magnetoresistive elements 1 are connected in series, the number of magnetoresistive elements 1 provided in the magnetic measuring device 10 is limited to this. Not.

The magnetoresistive element 1 includes a magnetization fixed layer 6 whose magnetization direction is fixed, a magnetization free layer 7 whose magnetization direction is changed by an external magnetic field, and an insulation disposed between the magnetization free layer 7 and the magnetization fixed layer 6. This is an element in which the layer 8 is laminated. The magnetoresistive element 1 has a rectangular cross section in a direction orthogonal to the stacking direction.

The upper wiring layer 2 is formed in a plane perpendicular to the laminating direction of the magnetoresistive element 1 and is opposed to the magnetization free layer 7 of the magnetoresistive element 1 on the side opposite to the insulating layer 8 side. The lower wiring layer 3 is formed in a plane perpendicular to the laminating direction of the magnetoresistive element 1, and faces the magnetoresistive element 1 on the opposite side to the insulating layer 8 side with respect to the magnetization fixed layer 6. As shown in FIG. 1A, the upper wiring layer 2 and the lower wiring layer 3 are formed so as to alternate between the adjacent magnetoresistive elements 1.

The upper interlayer wiring 4 is suspended between the upper wiring layer 2 and the magnetization free layer 7. Further, the lower interlayer wiring 5 is provided between the lower wiring layer 3 and the magnetization fixed layer 6.

Here, in the magnetoresistive element 1, as described above, the magnetization direction of the magnetization free layer 7 is changed by the external magnetization, and the angle between the magnetization direction of the magnetization fixed layer 6 and the magnetization direction of the magnetization free layer 7. According to the difference, the electric resistance value of the insulating layer 8 changes due to the tunnel effect. For this reason, a sense current I that is a current for measuring the electrical resistance is passed through the magnetoresistive element 1 and the electrical resistance value of the magnetoresistive element 1 is measured to act on the magnetization free layer 7 of the magnetoresistive element 1. The magnetic field can be measured.

1B shows a path of the sense current I flowing through the magnetic measuring device 10 shown in FIG. 1A and a magnetic field B generated by the sense current I. FIG. As shown in FIGS. 1A and 1B, the sense current I flowing from the lower wiring layer 3 flows to the magnetoresistive element 1 through the lower interlayer wiring 5. Then, the current flows through the upper interlayer wiring 4, the upper wiring layer 2, and the upper interlayer wiring 4 to the next magnetoresistive element 1. Thereafter, the sense current I flows through the lower interlayer wiring 5 and the lower wiring layer 3. Thereafter, the sense current I flows to the next magnetoresistive element 1 in the same manner.

When the sense current I flows, a magnetic field B is generated. The magnetic field B generated by the sense current I becomes noise relative to the magnetism to be measured. In particular, among the sense currents I flowing through the upper wiring layer 2 and the lower wiring layer 3 provided in parallel to the magnetization free layer 7, the magnetic field B generated by the sense current I flowing immediately above and immediately below the magnetization free layer 7. The impact is great. However, in the magnetic measuring device 10 according to the present embodiment, the upper interlayer wiring 4 is provided between the upper wiring layer 2 and the magnetization free layer 7, and the lower interlayer is provided between the lower wiring layer 3 and the magnetization fixed layer 6. Wiring 5 is provided. Therefore, there is a certain distance between the upper wiring layer 2 and the lower wiring layer 3 and the magnetization free layer 7, and the influence of the magnetic field B generated by the sense current I can be reduced.

(Contrast with conventional technology)
Here, the effect of the present invention will be described with reference to FIG.

FIG. 16A is a schematic diagram of a magnetic measuring device 200 having a magnetoresistive element 201 that is conventionally used, and FIG. 16B is a magnetic measuring device shown in FIG. 2 is a diagram showing a sense current I flowing through 200 and a magnetic field B generated by the sense current I. FIG.

16A, the magnetic measuring device 200 includes a magnetoresistive element 201, an upper wiring layer 202, and a lower wiring layer 203. That is, the configuration is the same as that of the magnetic measuring device 10 except that the upper interlayer wiring 4 and the lower interlayer wiring 5 are not provided. Similarly to the magnetoresistive element 1, the magnetoresistive element 201 is an element in which a magnetization fixed layer 206, a magnetization free layer 207, and an insulating layer 208 are stacked.

In the magnetic measuring device 200, the upper wiring layer 202 is directly connected to the magnetization free layer 207, and the lower wiring layer 203 is directly connected to the magnetization fixed layer 206. Therefore, the magnetization free layer 207 has a structure that is easily affected by the magnetic field B generated by the sense current I that flows immediately above and immediately below the magnetization free layer 207.

For example, the thickness of the upper wiring layer 202 is 5 nm, the thickness of the magnetization free layer 207 is 3 nm, the sense current I is 1 × 10 ⁻¹¹ A, and the sense current I is the top surface of the upper wiring layer 202 (one from the magnetization free layer 207). Even if it is assumed that it flows through the farthest surface), magnetism with a magnetic flux density of 3 × 10 ⁻¹⁰ T acts on the center of the magnetization free layer 207. Here, when considering a magnetic measuring device for measuring biomagnetism, the magnetoencephalogram is about 1 × 10 ⁻¹⁵ to 1 × 10 ⁻¹² T, and the magnetocardiogram is 1 × 10 ⁻¹⁴ to 1 ×. It is about 10 ⁻¹⁰ T. Therefore, it is difficult to accurately measure biomagnetism unless the influence of the magnetic field B generated by the sense current I is reduced.

On the other hand, the magnetic measurement apparatus 10 according to the present embodiment has a certain distance between the upper wiring layer 2 and the lower wiring layer 3 and the magnetization free layer 7. Therefore, for example, if the distance between the magnetization free layer 7 and the upper wiring layer 2 is 3 μm and the sense current I is 1 × 10 ⁻¹¹ A, the magnetization free layer 7 has a magnetism with a magnetic flux density of 7 × 10 ⁻¹³ T. Works. In this way, the influence of the magnetic field B generated by the sense current I can be reduced, and even weak magnetism such as biomagnetism can be accurately measured.

[Embodiment 2]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 2 is a schematic diagram showing the magnetic measuring device 20 according to the present embodiment. As shown in FIG. 2, the magnetic measuring device 20 according to this embodiment includes a magnetoresistive element 1, an upper wiring layer 2, a lower wiring layer 3, an upper interlayer wiring (first interlayer wiring) 24, and a lower interlayer wiring (first interlayer wiring). 2 interlayer wiring) 25. That is, the magnetic measurement apparatus 20 according to the present embodiment is the same as that of the first embodiment except that the upper interlayer wiring 24 is provided instead of the upper interlayer wiring 4 and the lower interlayer wiring 25 is provided instead of the lower interlayer wiring 5. It is the structure similar to the magnetic measuring device 10 concerning.

The upper interlayer wiring 24 is suspended between the upper wiring layer 2 and the magnetization free layer 7 of the magnetoresistive element 1. The upper interlayer wiring 24 is formed such that a straight line L passing through the center of gravity in a plane perpendicular to the direction of the sense current I flowing through the upper interlayer wiring 24 passes through the center of gravity in a plane perpendicular to the thickness direction of the magnetization free layer 7. Has been. The lower interlayer wiring 25 is provided between the lower wiring layer 3 and the magnetization fixed layer 6 of the magnetoresistive element 1. The lower interlayer wiring 25 is formed such that a straight line L passing through the center of gravity in a plane perpendicular to the direction of the sense current I flowing through the lower interlayer wiring 25 passes through the center of gravity in a plane perpendicular to the thickness direction of the magnetization free layer 7. Has been.

That is, in the magnetic measurement apparatus 20 according to the present embodiment, the centers of gravity of the upper interlayer wiring 24, the magnetization free layer 7, and the lower interlayer wiring 25 are all on the same straight line (straight line L). Therefore, the sense current I flows vertically through the center of gravity in the plane perpendicular to the thickness direction of the magnetization free layer 7.

FIG. 3 is a schematic diagram showing the magnetic field B generated by the sense current I. FIG. 3A shows the sense current I flowing vertically through the center of gravity in a plane perpendicular to the thickness direction of the magnetization free layer 7. FIG. 3B shows a case where the sense current I flows vertically through a position deviating from the center of gravity in a plane perpendicular to the thickness direction of the magnetization free layer 7. In FIG. 3, the sense current I flows from the front side of the paper toward the back of the paper.

As can be seen from FIG. 3, the magnetic field B generated by the sense current I is formed in a plane perpendicular to the sense current I, that is, in a plane parallel to the magnetization free layer 7. The magnetic field B is formed clockwise on a concentric circle with the sense current I as the center.

Here, as shown in FIG. 3A, when the sense current I flows perpendicularly through the center of gravity of the magnetization free layer 7, the magnetic field B in the magnetization free layer 7 is distributed symmetrically. On the other hand, as shown in FIG. 3B, when the sense current I flows at a position deviating from the center of gravity of the magnetization free layer 7, the magnetic field B in the magnetization free layer 7 shows a biased distribution.

FIG. 4 is a diagram showing the distribution of the magnetic field B generated by the sense current I. FIG. 4A shows the distribution of the magnetic field B along the α-α line in FIG. FIG. 3B shows the distribution of the magnetic field B along the β-β line in FIG. 4 (a) and 4 (b) show the magnetic flux density when the sense current I is 1.0 × 10 ⁻¹¹ A, and the place where the sense current I flows is set to the 0 position. . For reference, FIGS. 4A and 4B show a magnetic flux density of 5.0 × 10 ⁻¹³ T, which is a magnetic flux density at the brain magnetic level, with white arrows.

As shown in FIG. 4B, when the sense current I flows at a position deviated from the center of gravity of the magnetization free layer 7, the direction of the magnetic field is reversed on the left and right of the place where the sense current I flows. However, it can be seen that the distribution of the magnetic field in the magnetization free layer 7 is biased left and right. It can also be seen that the magnetic field B generated by the sense current I has a magnetic flux density that is greater than the magnetic flux density at the brain magnetic level.

Here, since the magnetic field B generated by the sense current I is determined by the magnitude of the sense current I and the distance from the position where the sense current I flows, there are cases where there is a magnetic field to be measured and cases where there is no magnetic field to be measured. In both cases, it is possible to reduce the influence of the magnetic field B generated by the sense current I by passing the sense current I and measuring the electrical resistance value and taking the difference.

However, the sense current I may fluctuate due to noise components (for example, Johnson noise or shot noise). As shown in FIG. 4B, the magnetic field generated by the noise component includes the above-described measured magnetic field when the magnetic field is biased at the left and right of the position where the sense current I flows, and the measured magnetic field. Even if the difference from the case where there is no magnetic field is taken, the influence cannot be subtracted.

On the other hand, in the magnetic measuring device 20 according to the present embodiment, the sense current I flows through the center of gravity of the magnetization free layer 7. For this reason, as shown in FIG. 4A, the magnetic flux density is distributed in the center of the position (position 0) where the sense current I flows so as to cancel each other symmetrically in the magnetization free layer 7. In the free layer 7, there is no bias in the distribution of magnetic flux density. As a result, even if the sense current I fluctuates due to the noise component described above, it is generated by the sense current I including the noise component by taking the difference between when the measured magnetic field is present and when there is no measured magnetic field. The effect of the magnetic field B to be reduced can be reduced.

In the present embodiment, the center of gravity of the upper interlayer wiring 24, the magnetization free layer 7, and the lower interlayer wiring 25 is shown as being all on the same straight line. However, the center of gravity and the straight line L are not necessarily the same. If the respective centers of gravity are formed on substantially the same straight line, the same effect as that of the magnetic measurement device 20 according to the present embodiment can be obtained.

Further, in the present embodiment, the center of gravity of the upper interlayer wiring 24, the magnetization free layer 7 and the lower interlayer wiring 25 is shown as being all on the same straight line, but the present invention is not limited to this. That is, the upper interlayer wiring 24 (first interlayer wiring) is a second predetermined region in which a straight line (first straight line) passing through the first predetermined region including the center of gravity of the upper interlayer wiring 24 includes the center of gravity of the magnetization free layer 7. The lower interlayer wiring 25 (second interlayer wiring) is arranged such that a straight line (second straight line) passing through a third predetermined region including the center of gravity of the lower interlayer wiring 25 is the center of gravity of the magnetization free layer 7. The first predetermined region to the third predetermined region including the center of gravity are set in a range in which the magnetic flux density distribution is not biased in the magnetization free layer 7. Just do it. For example, a straight line passing through the center of gravity of the upper interlayer wiring 24 (first straight line) is arranged so as to pass near the center of gravity of the magnetization free layer 7 and a straight line passing through the center of gravity of the lower interlayer wiring 25 (second straight line) It may be configured to pass through the vicinity of the center of gravity of the magnetization free layer 7. Even in such a configuration, the magnetic field B generated by the sense current I flowing in the upper interlayer wiring 24 and the lower interlayer wiring 25 is symmetrically distributed in the magnetization free layer 7, so that the magnetic field B generated by the sense current I is Can be reduced.

A second line (first line) in which at least the upper interlayer wiring 24 (first interlayer wiring) passes through the first predetermined region including the center of gravity of the upper interlayer wiring 24 includes the center of gravity of the magnetization free layer 7. What is necessary is just to arrange | position so that a predetermined area may be passed. That is, it is sufficient that at least a straight line (first straight line) passing through the center of gravity of the upper interlayer wiring 24 passes near the center of gravity of the magnetization free layer 7. This is because there is an insulating layer 8 (not shown) and a magnetization fixed layer 6 between the lower interlayer wiring 25 and the magnetization free layer 7, so that there is a constant between the lower interlayer wiring 25 and the magnetization free layer 7. This is because the distance is provided. Therefore, the influence of the magnetic field B generated by the sense current I flowing through the lower interlayer wiring 25 on the magnetization free layer 7 is slight, and at least the upper interlayer wiring 24 (first interlayer wiring) has a center of gravity of the upper interlayer wiring 24. If the straight line passing through the first predetermined area including the first predetermined line passes through the second predetermined area including the center of gravity of the magnetization free layer 7, the influence of the magnetic field B generated by the sense current I can be sufficiently reduced. it can.

[Embodiment 3]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 5 is a schematic diagram showing the magnetic measurement device 30 according to the present embodiment. As shown in FIG. 5, the magnetic measuring device 30 according to the present embodiment includes a magnetoresistive element 31, an upper wiring layer 2, a lower wiring layer 3, an upper interlayer wiring 24, and a lower interlayer wiring 25. That is, the magnetic measurement device 30 according to the present embodiment has the same configuration as the magnetic measurement device 20 according to the second embodiment, except that the magnetic resistance device 31 is provided instead of the magnetoresistive device 1.

As with the magnetoresistive element 1, the magnetoresistive element 31 includes a magnetization fixed layer 36 whose magnetization direction is fixed, a magnetization free layer 37 whose magnetization direction is changed by an external magnetic field, and a magnetization free layer 37 and a magnetization fixed layer 36. Is an element in which an insulating layer 38 disposed between and is laminated. The magnetoresistive element 31 has a circular cross section (hereinafter simply referred to as a cross section) in a direction orthogonal to the direction in which the sense current I flows.

FIG. 6 is a diagram showing a distribution in the magnetization free layer 37 of the magnetic field B generated by the sense current I. FIG. 6 is a cross-sectional view of the magnetization free layer 37 in a direction orthogonal to the direction in which the sense current I flows, and the sense current I flows from the front of the paper to the back.

As shown in FIG. 6, in the magnetic measurement device 30 according to the present embodiment, since the cross section of the magnetoresistive element 31 is circular, the distribution of the magnetic field B generated by the sense current I is symmetric within the magnetization free layer 37. It will be continuous. Therefore, even if the sense current I fluctuates due to the above-described noise component, the influence of the magnetic field B generated by the sense current I including the noise component can be mitigated.

In the present embodiment, the case where all the cross sections of the magnetization fixed layer 36, the magnetization free layer 37, and the insulating layer 38 of the magnetoresistive element 31 are circular is shown, but the present invention is not limited to this. In order to mitigate the influence of the magnetic field B generated by the sense current I on the magnetic field to be measured, it is sufficient that at least the cross section of the magnetization free layer 37 is circular. Further, the cross section of the magnetization free layer 37 is not limited to a circle, but may be an ellipse.

[Embodiment 4]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 7 is a schematic diagram showing the magnetic measurement device 40 according to the present embodiment. As shown in FIG. 7, the magnetic measurement device 40 according to the present embodiment is similar to the magnetic measurement device 10 according to the first embodiment, in that the magnetoresistive element 1, the upper wiring layer 2, the lower wiring layer 3, and the upper interlayer wiring 4. , And a lower interlayer wiring 5. In addition, the magnetoresistive element 1 includes a magnetization fixed layer 6, a magnetization free layer 7, and an insulating layer 8. In FIG. 7, the members other than the magnetoresistive element 1 are shown by the flow path of the sense current I, and the same applies to FIGS. 8 to 11 described later.

In the magnetic measuring device 40 according to the present embodiment, the upper wiring layer 2 and the lower wiring layer 3 are formed in parallel to the cross section of the magnetization free layer 7, and the sense current I flowing through the upper wiring layer 2 and the lower wiring layer 3. Are the same and parallel. Therefore, as shown in FIG. 7, the magnetic fields B generated by the sense currents I flowing in the upper wiring layer 2 and the lower wiring layer 3 immediately above and immediately below the respective magnetization free layers 7 are opposite to each other in the magnetization free layer 7. And weaken the magnetic field. As a result, the influence of the magnetic field B generated by the sense current I on the magnetic field of the measurement target can be reduced.

(Modification)
Next, a modification of the magnetic measurement device 40 according to this embodiment will be described. As described above, in order for the magnetic field B generated by the sense current I to weaken each other in the magnetization free layer 7 of the magnetoresistive element 1, the upper wiring layer 2 and the lower wiring layer immediately above and immediately below each magnetization free layer 7. It is only necessary that the sense currents I flowing through 3 have the same direction and are parallel.

FIG. 8 is a schematic diagram showing a magnetic measurement device 50 according to a modification of the present embodiment. The magnetic measurement device 50 includes an upper wiring layer 52 and a lower wiring layer 53 that are different from the magnetic measurement device 40. As shown in FIG. 8, the upper wiring layer 52 and the lower wiring layer 53 of the magnetic measuring device 50 are formed in a plane parallel to the cross section of the magnetization free layer 7 and have a substantially U shape. The upper wiring layer 52 and the lower wiring layer 53 are arranged alternately with respect to the adjacent magnetoresistive elements 1. In addition, the upper wiring layer 52 and the lower wiring layer 53 are arranged so that the sense currents I flowing through the upper wiring layer 52 and the lower wiring layer 53 are in the same direction and parallel immediately above and immediately below the respective magnetization free layers 7. Are arranged on different sides with respect to the parallel arrangement direction of the magnetoresistive elements 1. That is, the sense current I flowing from the upper interlayer wiring 4 or the lower interlayer wiring 5 to the upper wiring layer 52 or the lower wiring layer 53 passes through the upper wiring layer 52 or the lower wiring layer 53 formed in a substantially U shape. The flow direction is changed by 180 degrees, and the flow flows to the next upper wiring layer 52 or lower wiring layer 53.

As described above, if the sense currents I flowing through the upper wiring layer 52 and the lower wiring layer 53 are the same and parallel to each other immediately above and immediately below the respective magnetoresistive elements 1, the magnetic field B generated by the sense current I is used. Cancel each other out in the magnetization free layer 7. Therefore, the shape of the upper wiring layer 52 or the lower wiring layer 53 is such that the sense currents I flowing through the upper wiring layer 52 and the lower wiring layer 53 immediately above and immediately below the respective magnetization free layers 7 have the same direction and are parallel. There is no particular limitation.

(Comparative example)
On the other hand, a case will be described in which the sense currents I flowing through the upper wiring layer and the lower wiring layer are parallel but opposite to each other immediately above and directly below the respective magnetization free layers 7.

FIG. 9 is a schematic diagram showing a magnetic measuring device 60 according to a comparative example of the present embodiment. Similar to the magnetic measurement device 50, the magnetic measurement device 60 includes an upper wiring layer 62 and a lower wiring layer 63 that are formed in a substantially U-shape. In the magnetic measurement device 60, the parallel arrangement of the magnetoresistive elements 1 is performed so that the sense currents I flowing through the upper wiring layer 62 and the lower wiring layer 63 are parallel and opposite to each other directly above and directly below the respective magnetization free layers 7. It is arranged on the same side with respect to the installation direction.

As shown in FIG. 9, the magnetic fields B generated by the sense current I flowing through the upper wiring layer 62 and the lower wiring layer 63 immediately above and below the magnetization free layer 7 are in the same direction in each magnetization free layer 7. For this reason, in the magnetization free layer 7, the magnetic fields B strengthen each other and affect the magnetic field to be measured. In particular, when measuring a weak magnetic field such as biomagnetism, the influence of the magnetic field B generated by the sense current I is large.

[Embodiment 5]
Another embodiment of the present invention will be described with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

FIG. 10 is a schematic diagram showing a magnetic measuring device 70 according to the present embodiment. As shown in FIG. 10, the magnetic measurement device 70 according to the present embodiment is similar to the magnetic measurement device 40 according to the fourth embodiment, in which the magnetoresistive element 1, the upper wiring layer 2, the lower wiring layer 3, and the upper interlayer wiring are used. 4 and a lower interlayer wiring 5 are provided. Here, in the magnetization free layer 7, the center of the direction in which the sense current I flows (the stacking direction of the magnetoresistive element 1) flows as the center point O.

As shown in FIG. 10, in the upper interlayer wiring 4 and the lower interlayer wiring 5 according to this embodiment, the distance r from the center point O to the flow path of the sense current I in the upper wiring layer 2 and the lower wiring layer 3 is mutually equal. It is formed to be equal.

As described above, in the magnetic measurement device 70 according to the present embodiment, the sense current I flows in the same direction and in parallel immediately above and immediately below the magnetization free layer 7, and from the center of the magnetization free layer 7, The distance r to the flow path of the sense current I of the upper wiring layer 2 and the lower wiring layer 3 is equal to each other. For this reason, the magnetic field B generated by the sense current I is opposite in the center of the magnetization free layer 7 and has the same intensity, and weakens each other.

In the present embodiment, the distance from the center of the magnetization free layer 7 to the flow path of the sense current I in the upper wiring layer 2 and the flow path of the sense current I in the lower wiring layer 3 from the center of the magnetization free layer 7. However, if the sense current I flows in the same direction and in parallel immediately above and directly below the magnetization free layer 7, the distance from the center of the magnetization free layer 7 to the upper wiring layer is shown. 2 and the lower wiring layer 3 may be formed so that the distance to the flow path of the sense current I is substantially equal. That is, the distance from the center of the magnetization free layer 7 to the flow path of the sense current I of the upper wiring layer 2 and the distance from the center of the magnetization free layer 7 to the flow path of the sense current I of the lower wiring layer 3 are: It is only necessary that the magnetic field B generated by the sense current I is set at such a distance that it is in the opposite direction at the center of the magnetization free layer 7 and has the same strength and weakens each other.

(effect)
Next, effects of the magnetic measurement device 70 according to the present embodiment will be described.

First, the influence of the magnetic field B generated by the sense current I flowing through the upper wiring layer 202 and the lower wiring layer 203 on the magnetization free layer 207 will be described with reference to FIG.

Here, the thickness of the upper wiring layer 202 and the lower wiring layer 203 is 5 nm, the thickness of the magnetization free layer 207 is 3 nm, the thickness of the insulating layer 208 is 2 nm, the thickness of the magnetization fixed layer 206 is 26 nm, and the sense current I is 1 × 10. ^{It is} assumed that ⁻¹¹ A, and the sense current I flows through the uppermost surface of the upper wiring layer 202 and the lowermost surface of the lower wiring layer (the surface farthest from the magnetization free layer 207). Then, at the center of the magnetization free layer 207, magnetism with a magnetic flux density of 3 × 10 ⁻¹⁰ T acts by the sense current I flowing through the upper wiring layer 202, and 0.6 by the sense current I flowing through the lower wiring layer 203. Magnetism with a magnetic flux density of × 10 ⁻¹⁰ T acts.

Here, currents flowing through the upper wiring layer 202 and the lower wiring layer 203 are parallel to each other and in the same direction. Therefore, the magnetic fields B generated by the sense current I at the center of the magnetization free layer 207 cancel each other, and a 2.4 × 10 ⁻¹⁰ T magnetic field remains.

It can be seen that this is a large magnetic field compared to the magnetoencephalogram (1 × 10 ⁻¹⁵ to 1 × 10 ⁻¹² T) and the magnetocardiogram (1 × 10 ⁻¹⁴ to 1 × 10 ⁻¹⁰ T). On the other hand, the magnetic measuring device 70 according to the present embodiment not only makes the direction in which the sense current I flows parallel and the same direction, but also sense currents in the upper wiring layer 2 and the lower wiring layer 3 from the center of the magnetization free layer 7. By making the distances r to I equal to each other, the magnetic field B generated by the sense current I flowing through the upper wiring layer 2 and the magnetic field B generated by the sense current I flowing through the lower wiring layer 3 are within the magnetization free layer 7. Thus, the magnetic fields B generated by the sense current I can be weakened in the magnetization free layer 7 because they are distributed in opposite directions and with the same intensity. Therefore, even when biomagnetism such as brain magnetism or magnetocardiogram is used as the magnetic field to be measured, the influence of the magnetic field B generated by the sense current I flowing through the upper wiring layer 2 and the lower wiring layer 3 Thus, even if the magnetic field is weak, such as biomagnetism, the measurement can be performed accurately.

(Modification 1)
Next, a modified example of the magnetic measurement device 70 according to the present embodiment will be described. FIG. 11 is a schematic diagram showing a magnetic measurement device 80 according to the first modification of the present embodiment. The magnetic measuring device 80 includes a magnetoresistive element 1, an upper wiring layer 82, a lower wiring layer 83, an upper interlayer wiring 84, and a lower interlayer wiring 85.

The upper wiring layer 82 and the lower wiring layer 83 of the magnetic measuring device 80 have substantially the same shape as the upper wiring layer 52 and the lower wiring layer 53 of the magnetic measuring device 50 shown in FIG. . The upper interlayer wiring 84 and the lower interlayer wiring 85 are the same as the upper interlayer wiring 74 and the lower interlayer wiring 75 of the magnetic measuring device 70 shown in FIG. The distance r from the point O to the flow path of the sense current I in the upper wiring layer 82 and the lower wiring layer 83 is formed to be equal to each other.

Even if the magnetic measuring device 80 has such a configuration, the same effect as the magnetic measuring device 70 according to the fifth embodiment can be obtained.

(Modifications 2 and 3)
FIG. 12 is a schematic diagram showing a modification of the magnetic measurement device 70 according to the present embodiment. FIG. 12A shows the magnetic measurement device 90 according to the modification 2, and FIG. The magnetic measuring device 100 which concerns on the modification 3 is shown.

The magnetic measurement device 90 according to Modification 2 has substantially the same configuration as the magnetic measurement device 20 shown in FIG. That is, the magnetic measurement device 90 is similar to the magnetic measurement device 20 except that the magnetic measurement device 20 includes an upper interlayer wire 94 instead of the upper interlayer wire 24 and a lower interlayer wire 95 instead of the lower interlayer wire 25. Are the same.

Similar to the upper interlayer wiring 74 and the lower interlayer wiring 75 of the magnetic measuring device 70, the upper interlayer wiring 94 and the lower interlayer wiring 95 are connected to the upper wiring layer 22 and the lower wiring from the center point O of the magnetization free layer 7 of the magnetoresistive element 1. The distance r to the flow path of the sense current I in the layer 23 is formed to be equal to each other.

Even if the magnetic measuring device 90 has such a configuration, the same effect as the magnetic measuring device 70 according to the fifth embodiment can be obtained.

The magnetic measurement device 100 according to Modification 3 has substantially the same configuration as the magnetic measurement device 30 shown in FIG. That is, the magnetic measuring device 100 is similar to the magnetic measuring device 30 except that the upper interlayer wiring 104 is provided instead of the upper interlayer wiring 34 of the magnetic measuring device 30 and the lower interlayer wiring 105 is provided instead of the lower interlayer wiring 35. Are the same.

Similar to the upper interlayer wiring 74 and the lower interlayer wiring 75 of the magnetic measuring device 70 according to the fifth embodiment, the upper interlayer wiring 104 and the lower interlayer wiring 105 are located above the center point O of the magnetization free layer 7 of the magnetoresistive element 1. The distance r to the flow path of the sense current I in the wiring layer 32 and the lower wiring layer 33 is formed to be equal to each other.

Even if the magnetic measuring device 100 has such a configuration, the same effect as that of the magnetic measuring device 70 according to the fifth embodiment can be obtained.

In the magnetic measuring devices 80 to 100 of the first to third modifications, the distance from the center of the magnetization free layer 7 to the flow path of the sense current I of the upper wiring layer 2 and the center of the magnetization free layer 7 to the lower part The distance to the flow path of the sense current I of the wiring layer 3 is not necessarily equal, and the magnetic field B generated by the sense current I is in the opposite direction at the center of the magnetization free layer 7 and has the same strength. It is sufficient that the distance is set so as to weaken each other.

[Embodiment 6]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Magnetic measurement unit)
FIG. 13A is a schematic view showing the magnetic measurement unit 110 according to the present embodiment, and FIG. 13B is a partially enlarged view of the cell 113 provided in the magnetic measurement unit 110. As shown in FIG. 13, the magnetic measurement unit 110 is arranged so that a plurality of signal lines 111 extending in the row direction and a plurality of scanning lines 112 extending in the column direction intersect with each other. A plurality of cells 113 are arranged in an array shape (lattice shape) in each of the enclosed regions, and are configured by a substantially square active matrix substrate.

Each of the plurality of cells 113 includes a magnetic measuring device 114 in which a plurality of magnetoresistive elements 1 are connected in series, and a switching element 115 made of an oxide semiconductor formed on an insulating surface of the substrate. .

One end of the magnetic measurement device 114 is connected to the scanning line 112 via the switching element 115, and the other end is connected to the signal line 111. Here, the magnetic measurement device 114 is any one of the above-described magnetic measurement devices 10, 20, 30, 40, 50, 70, 80, 90, and 100.

In the magnetic measurement unit 110 according to the present embodiment, an input signal from a certain scanning line 112 is in a live line state, and a sense current I is supplied to a certain signal line 111, so that one cell 113 is selected. Can be measured. In this manner, the magnetic resistance in each cell 113 can be measured by sequentially switching the scanning line 112 to be in a live line state and the signal line 111 to which the sense current I is input. In addition, since the cells 113 are arranged in a lattice shape, the value of the magnetoresistance can be obtained two-dimensionally, thereby obtaining a two-dimensional distribution of the magnetic field to be measured. .

In addition, by using an oxide semiconductor with excellent off-leakage characteristics as the switching element 115, the influence of leakage current from other cells 113 in the array can be reduced. Therefore, for example, even when the sense current I is set to a low current of 1 × 10 ⁻¹² A or less, the magnetic resistance of each cell 113 can be measured.

In the above-described embodiment, an oxide semiconductor element having excellent off-leakage characteristics is used as the switching element 115. However, if it can be applied in consideration of the influence of the sense current I on the magnetic field to be measured. Other semiconductor elements may be used as the switching element 115.

(Magnetic measurement system and magnetic measurement method)
Next, a magnetic measurement system 120 including the magnetic measurement unit 110 and a magnetic measurement method using the magnetic measurement system 120 will be described with reference to FIGS. 14 and 15.

FIG. 14 is a block diagram showing components of the magnetic measurement system 120 according to the present embodiment. As shown in FIG. 14, the magnetic measurement system 120 includes a magnetic measurement unit 110, a power source 121, a difference detection device 122, and a magnetic calculation device 123.

The power supply 121 is connected to the magnetic measurement unit 110 and applies a sense current I having a predetermined magnitude to the cell 113 of the magnetic measurement unit 110.

The difference detection device 122 is connected to the magnetic measurement unit 110. The difference detection device 122 performs magnetic measurement in the presence of the first output voltage, which is the output voltage when the sense current I is applied to the magnetic measurement unit 110 in the absence of the magnetic field to be measured, and the magnetic field to be measured. A second output voltage that is an output voltage when the sense current I is applied to the unit 110 is measured, and a difference between the first output voltage and the second output voltage is detected.

The magnetism calculation device 123 is connected to the difference detection device 122, and calculates the magnetic field of the measurement target using the difference between the first output voltage and the second output voltage detected by the difference detection device 122.

FIG. 15 is a flowchart showing a flow of a magnetic measurement method using the magnetic measurement system 120. First, a predetermined sense current I is applied to the magnetic measurement unit 110 by the power supply 121 in a state where there is no magnetic field to be measured (S1). The difference detection device 122 measures the output voltage of the magnetic measurement unit 110 (S2) and records it as the first output voltage (S3) (first step). Next, a predetermined sense current I is applied to the magnetic measurement unit 110 by the power source 121 in the state where the magnetic field to be measured is present (S4), and the difference detection device 122 measures the output voltage of the magnetic measurement unit 110. (S5) and recorded as the second output voltage (S6) (second step). Finally, the difference detection device 122 detects the difference between the first output voltage and the second output voltage, and the magnetic calculation device 123 calculates the magnetic field to be measured using the difference (S7) (third step) ).

As described above, the magnetic measurement system 120 and the magnetic measurement method using the magnetic measurement system 120 according to the present embodiment set the sense current I to a predetermined value so that the magnetic field B generated by the sense current I is a constant value. It can be. In addition, the output voltage is measured when there is no magnetic field to be measured and there is a magnetic field B generated by the sense current I, and then there is a magnetic field to be measured and there is also a magnetic field B generated by the sense current. Measure the output voltage. Therefore, the influence of the magnetic field B can be taken into account by the sense current I, and the magnetic field to be measured can be accurately measured.

In all the above-described embodiments, the example in which the magnetization free layer is disposed above the magnetization fixed layer has been described. However, in the magnetoresistive element, the magnetization free layer may be disposed below the magnetization fixed layer. Good. Furthermore, the magnetic field to be measured is not limited to biomagnetism, and the above-described magnetic measurement device, magnetic measurement unit, magnetic measurement system, and magnetic measurement method can be widely used for magnetic measurement.

[Summary]
The magnetic measurement apparatus 10 according to the first aspect of the present invention includes a magnetization free layer 7 whose magnetization direction is changed by an external magnetic field, a magnetization fixed layer 6 whose magnetization direction is fixed, and the magnetization free layer 7 and the magnetization fixed layer. 6 and a magnetoresistive element 1 in which an insulating layer 8 disposed between the magnetoresistive element 1 and the magnetization free layer 7 is opposed to the insulating layer 8 side opposite to the first wiring layer (upper wiring layer 2). ) And a second wiring layer (lower wiring layer 3) facing the magnetization fixed layer 6 on the side opposite to the insulating layer 8 side, and the first wiring with respect to the magnetoresistive element 1 A magnetic measuring device 10 for measuring magnetism by flowing a sense current I from a layer (upper wiring layer 2) or the second wiring layer (lower wiring layer 3), the first wiring layer (upper wiring layer 2) When the first interlayer wiring (upper interlayer wiring 4) is provided between the magnetic free layer 7 and the magnetization free layer 7, , Second layer interconnects (lower interlayer wiring 5) is vertically between the second wiring layer (lower wiring layer 3) and the fixed magnetization layer 6.

According to the above configuration, the first interlayer wiring (upper interlayer wiring 4) is interposed between the first wiring layer (upper wiring layer 2) and the magnetization free layer 7, and the second wiring layer (lower wiring layer 3) is magnetized. By providing the second interlayer wiring (lower interlayer wiring 5) between the fixed layer 6 and the first free wiring layer (upper wiring layer 2) and the second wiring layer (lower wiring layer 3) to the magnetization free layer 7. The distance can be increased. Thereby, the influence of the magnetic field B generated by the sense current I is reduced, and even a weak magnetic field can be measured accurately.

The magnetic measurement apparatus 20 according to Aspect 2 of the present invention is the magnetic measurement apparatus 20 according to Aspect 1, wherein the first interlayer wiring (upper interlayer wiring 24) includes a center of gravity of the first interlayer wiring (upper interlayer wiring 24). Is arranged so as to pass through a second predetermined region including the center of gravity of the magnetization free layer 7, and the first predetermined region and the second predetermined region including the center of gravity are respectively in the magnetization free layer 7. The magnetic flux density distribution may be set in a range where no deviation occurs.

According to the above configuration, the magnetic field B generated by the sense current I flowing through the first interlayer wiring (upper interlayer wiring 24) close to the magnetization free layer 7 is distributed symmetrically in the magnetization free layer 7. Therefore, the influence of the magnetic field B generated by the sense current I flowing through the first interlayer wiring (upper interlayer wiring 24) can be reduced.

In the magnetic measurement apparatus 20 according to Aspect 3 of the present invention, in the Aspect 2, the second interlayer wiring (lower interlayer wiring 25) is a third predetermined region including the center of gravity of the second interlayer wiring (lower interlayer wiring 25). Is arranged so that it passes through a second predetermined region including the center of gravity of the magnetization free layer 7, and the third predetermined region including the center of gravity is biased in the distribution of magnetic flux density in the magnetization free layer 7. It may be set in a range that does not occur.

According to the above configuration, the magnetic field B generated by the sense current I flowing through the second interlayer wiring (lower interlayer wiring 25) is distributed symmetrically in the magnetization free layer 7. Therefore, the influence of the magnetic field B generated by the sense current I flowing through the second interlayer wiring (lower interlayer wiring 25) can be reduced.

The magnetic measurement apparatus 20 according to Aspect 4 of the present invention is the magnetic measurement apparatus 20 according to Aspect 3, wherein the first interlayer wiring (upper interlayer wiring 24) and the second interlayer wiring (lower interlayer wiring 25) are the first straight line and the first interlayer wiring. Two straight lines may be arranged so as to pass on the same straight line (straight line L).

According to the above configuration, the centroids of the first interlayer wiring (upper interlayer wiring 24), the magnetization free layer 7, the second interlayer wiring (lower interlayer wiring 25), and the magnetization fixed layer 6 are on the same straight line (straight line L). By disposing, the magnetic field B generated by the sense current I is distributed so as to cancel each other out in the magnetization free layer 7, so that the influence of the magnetic field B generated by the sense current I can be reduced.

The magnetic measurement device 30 according to aspect 5 of the present invention is the magnetic measurement apparatus 30 according to any one of the aspects 2 to 4, wherein at least the magnetization free layer 37 has a circular or elliptical cross section in a direction orthogonal to the direction in which the sense current I flows. There may be.

According to the above configuration, the magnetic field B generated by the sense current I is symmetrical and continuous in the magnetization free layer 37. Therefore, even if the sense current I fluctuates due to the noise component, the influence of the magnetic field B generated by the sense current I including the noise component can be reduced.

The magnetic measurement device 40 according to Aspect 6 of the present invention is the magnetic measurement apparatus 40 according to any one of the Aspects 1 to 5, wherein the sense current I that flows in the first wiring layer (upper wiring layer 2) and the second wiring layer (lower wiring). The sense current I flowing in the layer 3) may be in the same direction and parallel.

According to the above configuration, the magnetic field B generated by the sense current I flowing in the first wiring layer (upper wiring layer 2) and the magnetic field B generated by the sense current I flowing in the second wiring layer (lower wiring layer 3) are The magnetic free layers 7 are distributed so as to cancel each other. Thereby, the influence of the magnetic field B generated by the sense current I can be reduced.

In the magnetic measurement apparatus 70 according to the seventh aspect of the present invention, the sense current I in the first wiring layer (upper wiring layer 2) from the center (center point O) in the stacking direction of the magnetization free layer 7 in the sixth aspect. The distance r to the flow path is substantially equal to the distance r from the center (center point O) in the stacking direction of the magnetization free layer 7 to the flow path of the sense current I in the second wiring layer (lower wiring layer 3). Also good.

According to the above configuration, the distances from the first wiring layer (upper wiring layer 2) and the second wiring layer (lower wiring layer 3) to the magnetization free layer 7 are made substantially equal to each other in the magnetization free layer 7. The magnetic fields B generated by the current I can be distributed so as to cancel each other.

A magnetic measurement unit 110 according to Aspect 8 of the present invention includes a plurality of cells 113 to which the magnetic measurement device 114 according to any one of Aspects 1 to 7 and a switching element 115 are connected, and the cells 113 are arranged in an array. Has been placed.

According to the above configuration, the magnetic field distribution can be measured two-dimensionally by arranging the cells 113 including the magnetic measurement device 114 in an array.

In the magnetic measurement unit according to aspect 9 of the present invention, in the aspect 8, the switching element 115 may be an oxide semiconductor element.

According to the above configuration, by using an oxide semiconductor element made of an oxide semiconductor having excellent off-leakage characteristics as the switching element 115, the sense current I can be reduced and generated by the sense current I. The influence of the magnetic field can be reduced.

The magnetic measurement system 120 according to the tenth aspect of the present invention includes the magnetic measurement unit 110 according to the eighth or ninth aspect, a power supply 121 that applies a sense current I to each of the plurality of cells 113 in the magnetic measurement unit 110, When there is no magnetic field to be measured, when the power supply 121 applies a sense current I to each of the cells 113, the first output voltage measured from each cell 113 and the magnetic field to be measured are present. In addition, a difference detection device 122 that detects a difference from a second output voltage measured from each cell 113 by applying a sense current I to each of the cells 113 by the power supply 121 and detected by the difference detection device 122. And a magnetism calculation device 123 that calculates the magnetism of the measurement target.

According to the above configuration, the difference detection device 122 measures the output voltage by flowing the sense current I in the absence of the magnetic field to be measured. Therefore, it is possible to perform measurement taking into account the influence of the magnetic field B generated by the sense current I, and to accurately measure the magnetic field to be measured.

The magnetic measurement method according to the eleventh aspect of the present invention is a magnetic measurement method for measuring the magnetism of a target to be measured by passing a sense current I through the magnetic measurement unit 110 according to the eighth or ninth aspect. A first step of measuring the first output voltage by passing the sense current I when there is no magnetism to be measured, and a second output by passing the sense current I when the magnetism to be measured is present. A second step of measuring a voltage; and a magnetism to be measured by using a difference between the first output voltage measured in the first step and the second output voltage measured in the second step. 3 steps.

According to said method, there exists an effect similar to the said magnetic measurement unit 110, the measurement which considered the influence of the magnetic field B which the sense electric current I generate | occur | produces can be performed, and the magnetic field of to-be-measured object can be measured correctly. It becomes possible.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

The present invention can be used in a magnetic measuring device for measuring magnetism.

1 magnetoresistive element 2 upper wiring layer (first wiring layer)
3 Lower wiring layer (second wiring layer)
4, 24 Upper interlayer wiring (first interlayer wiring)
5, 25 Lower interlayer wiring (second interlayer wiring)
6 Magnetization fixed layer 7, 37 Magnetization free layer 8 Insulation layer 10, 20, 30, 40, 70, 114 Magnetic measurement device 110 Magnetic measurement unit 113 Cell 115 Switching element 120 Magnetic measurement system 121 Power supply 122 Difference detection device 123 Magnetic calculation device I sense current B magnetic field L straight line r distance O center point

Claims (11)

1. Magnetoresistive element in which a magnetization free layer whose magnetization direction is changed by an external magnetic field, a magnetization fixed layer whose magnetization direction is fixed, and an insulating layer disposed between the magnetization free layer and the magnetization fixed layer are stacked When,
   A first wiring layer facing the magnetization free layer on the side opposite to the insulating layer;
   A second wiring layer facing the magnetization pinned layer on the side opposite to the insulating layer side,
   A magnetic measuring device that measures magnetism by flowing a sense current from the first wiring layer or the second wiring layer to the magnetoresistive element,
   A first interlayer wiring is suspended between the first wiring layer and the magnetization free layer, and a second interlayer wiring is suspended between the second wiring layer and the magnetization fixed layer. Magnetic measuring device characterized by.
2. The first interlayer wiring is arranged such that a first straight line passing through a first predetermined region including the center of gravity of the first interlayer wiring passes through a second predetermined region including the center of gravity of the magnetization free layer,
   Each of the first predetermined area and the second predetermined area including the center of gravity is
   The magnetic measurement apparatus according to claim 1, wherein the magnetic free density layer is set in a range in which the magnetic flux density distribution is not biased.
3. The second interlayer wiring is arranged such that a second straight line passing through a third predetermined region including the center of gravity of the second interlayer wiring passes through a second predetermined region including the center of gravity of the magnetization free layer,
   3. The magnetic measurement apparatus according to claim 2, wherein the third predetermined region including the center of gravity is set in a range in which the distribution of magnetic flux density is not biased in the magnetization free layer.
4. 4. The magnetic measuring apparatus according to claim 3, wherein the first interlayer wiring and the second interlayer wiring are arranged so that the first straight line and the second straight line pass on the same straight line.
5. 5. The magnetic measuring device according to claim 2, wherein at least the magnetization free layer has a circular or elliptical cross section in a direction orthogonal to a direction in which the sense current flows.
6. 6. The sense current flowing in the first wiring layer and the sense current flowing in the second wiring layer have the same direction and are parallel to each other. Magnetic measuring device.
7. The distance from the center in the stacking direction of the magnetization free layer to the sense current flow path in the first wiring layer is the distance from the center in the stacking direction of the magnetization free layer to the sense current flow path in the second wiring layer. The magnetic measurement apparatus according to claim 6, wherein the magnetic measurement apparatus is substantially equal to
8. A plurality of cells to which the magnetic measuring device according to any one of claims 1 to 7 and a switching element are connected,
   A magnetic measurement unit, wherein the cells are arranged in an array.
9. The magnetic measurement unit according to claim 8, wherein the switching element is an oxide semiconductor element.
10. A magnetic measurement unit according to claim 8 or 9,
    A power supply for applying a sense current to each of the plurality of cells in the magnetic measurement unit;
    When there is no magnetic field to be measured, when a sense current is applied to each of the cells by the power source, when there is a first output voltage measured from each cell and the magnetic field to be measured. A difference detection device that detects a difference from a second output voltage measured from each cell by applying a sense current to each of the cells by the power source;
    A magnetic calculation device that calculates the magnetism of the measurement target using the difference detected by the difference detection device;
    A magnetic measurement system comprising:
11. A magnetic measurement method for measuring magnetism of a measurement target by passing a sense current through the magnetic measurement unit according to claim 8 or 9,
    A first step of measuring a first output voltage by passing the sense current when there is no magnetism to be measured;
    A second step of measuring a second output voltage by flowing the sense current when there is magnetism to be measured;
    And a third step of calculating the magnetism to be measured by using a difference between the first output voltage measured in the first step and the second output voltage measured in the second step. Magnetic measurement method.

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