JP2002207071A - Magnetic sensing element and azimuth sensing system using the same - Google Patents

Abstract

(57) [Problem] To provide a small, lightweight, and highly sensitive magnetic sensing element. SOLUTION: TM originally manufactured by using a thin film technique or the like.
By configuring the magnetic sensing element 1 using the R element 2, the size and weight can be reduced, and one surface of the element 1 has a coercive force lower than the coercive force of the magnetic layer 4 and an anisotropic axis of the magnetic layer 4. 4
A magnetic field detection assisting soft magnetic film 7 set independently of the anisotropic axis of the magnetic field is used, and the magnetic force detection can be performed by separating the function by utilizing the difference in coercive force. The magnetic field sensitivity was improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensing element such as a geomagnetic sensor for measuring a magnetic field and for navigation, and an azimuth detecting system using the element.

[0002]

2. Description of the Related Art Conventionally, as this type of magnetic sensor, a magnetoresistive element (MR element), a magnetic impedance element (MI element), a flux gate sensor, a semiconductor Hall effect sensor, and the like have been used. Of these, the recently developed MI sensor has been actively improved in recent years because it is easy to make it thinner and smaller by using a magnetoresistive element called an MI element. Also, in the case of an MR element, the magnetic field strength can be detected based on a change in the high-frequency impedance caused by a magnetic field when a high-frequency current flows through the MR element.

[0003] Specific examples of magnetic detection means or methods using such elements include the following proposals.

[0004] For example, according to Japanese Patent Application Laid-Open No. 6-176930, a high sensitivity with improved sensitivity is obtained by annealing a magnetic wire of a magnetic inductance element while applying a direct current or a time-varying current. Sensors have been proposed. Further, Japanese Patent Application Laid-Open No. 6-253573 proposes a current detection circuit that can control the motor drive current with high accuracy by detecting the motor drive current with a magnetic inductance sensor. JP-A-7-181399 proposes a magneto-impedance element capable of detecting a current without using a bridge circuit by increasing the frequency of an energizing current. JP-A-9-318719 proposes a magnetic sensor circuit in which a magnetic impedance element is connected in an oscillation circuit to improve the detection sensitivity. According to JP-A-10-307145, there is proposed a tire rotation position detecting device in which the residual magnetization of a steel belt of a tire is differentially detected from outside using a lead plate composed of a pair of magnetic sensors and a magnetic material. ing. Further, according to Japanese Patent Application Laid-Open No. 11-109006, a high-frequency current is applied to the sensor unit, and a negative feedback coil is provided in an element whose impedance change is proportional to the magnetic field strength at that time, so that the output linearity with respect to the magnetic field is improved. The proposed magnetic impedance sensor has been proposed.

[0005]

However, such conventional magnetic detection sensors are not yet sufficient in terms of size and weight and sensitivity, and there is much room for improvement.

Accordingly, it is an object of the present invention to provide a small, lightweight, and highly sensitive magnetic sensing element.

In addition, it is another object of the present invention to provide an azimuth detecting system which can improve the accuracy of geomagnetic detection and the like by utilizing the above magnetic detecting element, and is effective for a navigation system and the like.

[0008]

According to the first aspect of the present invention,
Using a tunnel magnetoresistive effect element or a giant magnetoresistive effect element having a magnetic layer, a magnetic detection unit is a flat magnetic detection element that detects magnetism by flowing a current in a direction perpendicular to the film surface, A magnetic field-sensing auxiliary soft member which is arranged on one surface of the element and has a coercive force lower than the coercive force of the magnetic layer and whose anisotropic axis is set independently of the anisotropic axis of the magnetic layer. It has a magnetic film.

Therefore, by using a tunnel magnetoresistive element (TMR element) or a giant magnetoresistive element (GMR element) which is originally manufactured by using a thin film technique or the like, it is possible to reduce the size and size of the device.
In addition to being able to reduce the weight, the coercive force arranged on one surface of the element is lower than the coercive force of the magnetic layer, and its anisotropic axis is independent of the anisotropic axis of the magnetic layer. By providing a set magnetic field sensing auxiliary soft magnetic film, magnetic force detection can be performed by separating functions by utilizing the difference in coercive force.
The magnetic field sensitivity as a sensor can be improved. The soft magnetic film for assisting magnetic field sensing may be on the top surface or the bottom surface as long as it is one surface of the element.

According to a second aspect of the present invention, in the magnetic sensing element of the first aspect, the soft magnetic film for assisting magnetic field sensing is individually formed in the magnetic sensing portion as a plurality of magnetic films in an array. The magnetic layer is formed as one common electrode intersecting the plurality of magnetic films.

Therefore, in realizing the first aspect of the present invention, it is possible to easily form an array, and it is possible to widen the application.

According to a third aspect of the present invention, in the magnetic sensing element according to the first or second aspect, a high magnetic permeability layer is provided near the magnetic sensing portion and connected to the soft magnetic film for assisting magnetic field sensing. .

Therefore, since the high magnetic permeability layer connected to the soft magnetic film for assisting magnetic field sensing is provided in the vicinity of the magnetic sensing portion, the high magnetic permeability layer functions as a magnetic flux sink, and the sensitivity can be further improved. it can.

According to a fourth aspect of the present invention, in the magnetic sensing element of the first, second, or third aspect, a bulk magnetic body is disposed near the magnetic sensing portion.

Therefore, a magnetic permeability and coercivity far lower than those of the magnetic thin film can be realized, and a bulk type magnetic material having a characteristic of being hardly saturated due to a large amount of magnetic flux that can be handled is provided near the magnetic sensing portion, so that it is further improved. Sensitivity can be improved.

According to a fifth aspect of the present invention, in the magnetic sensing element of the third aspect, a bulk type magnetic body is disposed on the high magnetic permeability layer.

Therefore, since the bulk type magnetic material is provided on the high magnetic permeability layer near the magnetic sensing portion, the sensitivity can be further improved.

The invention according to claim 6 is the invention according to claims 1 to 5
In the magnetic sensing element according to any one of the above, the soft magnetic film for assisting magnetic field sensing is formed as a laminated structure of a plurality of soft magnetic layers on a non-magnetic layer.

Therefore, in order to realize the invention according to any one of the first to fifth aspects, a soft magnetic film for assisting magnetic field sensing is formed on the non-magnetic layer as a laminated structure of a plurality of soft magnetic layers. In addition, it is possible to prevent the formation of a return magnetic domain, thereby achieving low noise and high frequency (high-speed sampling), and further improving the element performance.

[0020] The invention according to claim 7 is the invention according to claims 1 to 6.
In the magnetic sensing element according to any one of the above, the soft magnetic film for assisting magnetic field sensing is formed in a circular planar shape.

Therefore, in order to realize the invention of any one of claims 1 to 6, the soft magnetic film for assisting magnetic field sensing has a circular planar shape (a perfect circular shape, an elliptical shape, etc.).
Since the magnetostatic energy can be made smaller, the generation of magnetic charge is reduced, and the stability of the magnetic domain can be expected.
Low noise or high sensitivity can be achieved, and element performance can be further improved.

The invention according to claim 8 is the first to sixth aspects.
In the magnetic sensing element according to any one of the above, the soft magnetic film for assisting magnetic field sensing is formed by being divided into a plurality of portions.

Therefore, in realizing the invention according to any one of claims 1 to 6, the soft magnetic film for assisting the sensing of the magnetic field is divided into a plurality of portions so that the size of each can be reduced. For example, the generation of return magnetic domains can be suppressed, noise can be reduced, and the sensitivity can be further improved by making the anisotropy uniform.

According to the ninth aspect of the present invention, there are provided the first to sixth aspects.
In the magnetic sensing element according to any one of the above, a plurality of cuts are formed in the soft magnetic film for assisting magnetic field sensing.

Therefore, in order to realize the invention according to any one of claims 1 to 6, the size of each of the magnetic field sensing assisting soft magnetic films can be reduced by forming the soft magnetic film into a plurality of cuts. For example, the generation of return magnetic domains can be suppressed, noise can be reduced, and the sensitivity can be further improved by making the anisotropy uniform.

According to a tenth aspect of the present invention, in the magnetic sensing element according to any one of the first to ninth aspects, there is provided a reset magnetic field generating means for returning the magnetization state of the magnetic sensing unit to a predetermined state.

Therefore, even in the case where the operating point is changed due to the magnetization of the magnetic detection unit due to the influence of the temporary strong magnetic field and erroneous detection is performed, the reset magnetic field generation means is used to detect the magnetic detection unit. By returning the magnetization state to a predetermined state,
Thereafter, a normal detection operation can be performed.

According to an eleventh aspect of the present invention, in the magnetic sensing element of the tenth aspect, the reset magnetic field generating means includes a reset current wiring portion integrally formed near the magnetic sensing portion.

Therefore, by utilizing the reset current wiring portion integrally formed in the vicinity of the magnetic sensing portion, the tenth aspect is provided.
The described invention can be easily realized.

According to a twelfth aspect of the present invention, in the magnetic sensing element according to the tenth aspect, the reset magnetic field generating means includes an external coil for generating a reset magnetic field with respect to the magnetic detecting unit.

Therefore, by utilizing an external coil for generating a reset magnetic field for the magnetic detection unit, a tenth aspect is provided.
The described invention can be easily realized.

The azimuth detecting system according to the thirteenth aspect of the present invention is a plurality of magnetic sensing elements according to any one of the first to twelfth aspects, wherein the azimuth detecting systems are independently arranged in directions of three or more axis vectors to detect terrestrial magnetism. Detecting means for detecting vectors of three or more axes based on the detection outputs of these magnetic detection elements; and abnormality in the detection result based on the absolute value of the detection outputs of the magnetic detection elements and a preset threshold. Abnormality detecting means for judging whether or not the abnormality is detected, and a notifying means for notifying, when an abnormality is detected by the abnormality detecting means, that fact.

Therefore, when the present invention is applied to an azimuth detecting system in which terrestrial magnetism is to be detected, basically a high sensitivity is independently provided in directions of three or more axis vectors. The vector of three or more axes detected based on the detection output of the magnetic sensing element is used. At this time, the absolute value of the detection output of the magnetic sensing element is determined by comparing the absolute value of the detection output of the magnetic sensing element with a threshold obtained by adding a measurement margin to the measured geomagnetic intensity. It is determined whether or not there is an abnormality in the detection result by comparison, and when an abnormality is detected, the fact is notified so that use of an erroneous detection result can be prevented beforehand.

The azimuth detecting system according to the fourteenth aspect of the present invention is the azimuth detecting system according to the tenth, eleventh, or twelfth aspect of the present invention, wherein the plurality of magnetic sensing elements are independently arranged in directions of three or more axis vectors to detect geomagnetism. Detecting means for detecting vectors of three or more axes based on the detection outputs of these magnetic detection elements; and whether or not the detection result is abnormal based on the absolute value of the detection outputs of the magnetic detection elements and a preset threshold. Abnormality detecting means for judging whether the abnormality has been detected, notifying means for notifying that abnormality has been detected by the abnormality detecting means, and magnetization of the magnetic detecting section if an abnormality has been detected by the abnormality detecting means. Reset means for flowing a reset current to the reset magnetic field generating means so as to return the state to a predetermined state.

Therefore, the present invention is basically the same as the invention of the thirteenth aspect. However, in particular, when an abnormality is detected in the detection result, a reset current is supplied to the reset magnetic field generating means to cause the magnetic detection unit to operate. By resetting the magnetized state to the predetermined state and resetting, it is possible to avoid subsequent erroneous detection operations.

[0036]

FIG. 1 shows a first embodiment of the present invention.
A description will be given with reference to FIG. The magnetic sensing element 1 of the present embodiment is a TMR element (tunnel magnetoresistive element)
2 is used for a magnetic sensing portion, and basically includes a first layer 4 laminated on an insulating substrate 3, a second layer 5 of an insulating film, and a third layer as shown in FIG. The TMR element 2 having a structure in which a tunnel current flows from the first layer 4 through the second layer 5 to the third layer 6 is formed by a junction structure having a predetermined pattern with the fourth layer 7 and the fourth layer 7. Prepare for 8. Here, the fourth
The layer 7 functions as a soft magnetic film for assisting magnetic field sensing and an electrode,
The third layer 6 functions as a magnetic layer, and the first layer 4 functions as a magnetic layer and an electrode.

The TMR element used in the present embodiment is formed by a phenomenon found in recent years, that is, by a junction structure of a ferromagnetic material, an insulating film and a ferromagnetic material, and the magnetization of both ferromagnetic materials is reduced. It utilizes the phenomenon of ferromagnetic tunnel effect, in which the tunnel effect appears depending on the relative angle. For example,
JP-A-10-91925, JP-A-10-2552
As described in Japanese Unexamined Patent Publication No. 31 (Kokai), the S.I. Makesaw
a and V. Gafvert et al., IEEE Trans. Magn., M
AG-18,707 (1982) theoretically and experimentally shows that a tunnel effect is defined depending on the relative angle of magnetization of both magnetic layers in the magnetic / insulator / magnetic coupling. .

The detailed configuration of the magnetic sensing element 1 including such a TMR element 2 will be described including its manufacturing method. First, as shown in FIG. 1, a general non-magnetostrictive Fe20-Ni8 layer is formed as a first layer 4 on an insulating substrate such as quartz or glass, or a substrate 3 such as a Si substrate with an insulating layer.
The 0 film is formed to a thickness of 0.1 μm by a sputtering method. The Fe20-Ni80 film itself is a magnetoresistive element film, but the first layer 4 may be a film other than the Fe20-Ni80 film as long as it is a magnetic member having a high spin polarization. Magnetic properties such as coercive force may be selected according to the target magnetic field strength. Further, the Fe20-Ni80 film can also be manufactured by a plating method. Also, the first
Although the thickness of the layer 4 is set to 0.1 μm, it may be appropriately set according to the sensitivity and other necessary conditions.

Next, a general photolithography technique used in a semiconductor manufacturing process and RI using CF ₄ + H ₂
The first layer 4 is patterned by the E method (reactive ion etching method) as shown in FIG. Here, the first layer 4
Was formed in a linear shape so as to function as one electrode of the TMR element 2 and in a pattern shape having a width of 10 μm and a length of 1 mm, which was a size capable of functioning as a magnetoresistive element.
However, the dimensions and the shape of the first layer 4 may be appropriately changed according to the purpose. Further, the etching treatment may be a wet etching method, and in this case, aqua regia may be used as an etching solution.

Subsequently, as shown in FIG. 3, on the first layer 4, Al _{2 is used} as an insulating tunnel layer of the second layer 5.
An O ₃ film is formed by a sputtering method. For this film formation, an EB method (electron beam method), a CVD method (chemical vapor deposition method), or the like may be used. Then, as in the case of the first layer 4, a general photolithography technique and CF ₄ + H ₂
The second layer 5 is patterned by the RIE method using. As the insulating material of the second layer 5, other insulating materials such as SiO ₂ can function, but an Al ₂ O ₃ film is excellent in characteristics. After the Al film is formed, a method of performing plasma oxidation in the air or in a vacuum may be used. The second layer 5 serving as the insulating tunnel layer may be etched by wet etching. However, if the substrate 3 is also etched, the back surface of the substrate 3 needs to be protected by a resist or the like.

The substrate 3 may be an insulating substrate other than quartz or a flexible insulating substrate using PET (polyethylene terephthalate), polyimide, or the like. Depending on the design rule, a step of forming a film from the beginning using a metal mask may be used instead of the photolithography step.

Thereafter, as shown in FIG. 4, on the second layer 5 which is an insulating tunnel layer, Fe-Co5
A zero film is formed by a sputtering method, and is patterned into a pattern orthogonal to the pattern of the first layer 4 by a photolithography method as in the case of the first layer 4. This third layer 6 is also the first layer
As in the case of the layer 4, any other material having a high spin polarization may be used. Further, another antiferromagnetic film is provided to adopt an exchange mutual layer structure, that is, a spin valve structure. You may do so.

Further, in the present embodiment, as shown in FIG. 5, a fourth layer 7 is formed on the third layer 6 as a soft magnetic film for assisting magnetic field sensing. This fourth layer 7 is the first layer 4
And the anisotropic axis is formed so as to be independent of the anisotropic axis of the first layer 4.
More specifically, Ni-Fe prepared by changing the film forming conditions
Film and other magnetic materials such as CuMo permalloy film and Co
It is formed of a ZrNb amorphous film or the like.
The anisotropic axis can be changed by changing the magnetization method at the time of film formation or changing the annealing conditions between the film formation of the first layer 4 to the third layer 6 and the film formation of the fourth layer 7. I try to be independent. In the present embodiment, the fourth layer 7 is formed of, for example, a CoZrNb amorphous film.

In the magnetic sensing element 1 having such a configuration, when the current flows in the direction perpendicular to the film surface to the magnetic sensing portion 8 using the first layer 4 and the fourth layer 7 as electrodes, the change in the current is minute. A detection method of detecting with an ammeter (not shown) is employed. In this detection operation, an external magnetic field to be detected is applied to the magnetic detection unit 8. In this case, the coercive force is set to be lower than the coercive force of the first layer 4 while being arranged on one surface of the magnetic sensing element 1 and changing the film forming conditions, and the anisotropic axis of the first layer 4 is changed. Independently of the anisotropic axis of
Since the fourth layer 7 (soft magnetic film for assisting magnetic field sensing) is provided shifted by 0 °, the difference between the original coercive force and the difference between the magnetization of the magnetic film in the easy axis direction and the hard axis direction can be utilized. It is known that the third layer 6 is large with respect to the MR change, so that the optimum function separation as a sensor can be achieved and the magnetic field sensitivity can be improved. That is, high sensitivity can be achieved. Further, according to the magnetic sensing element 1 of the present embodiment, basically, the TMR element 2 is
Since the sensor can be reduced in size and weight, and can be detected with high sensitivity as described above, when applied to an azimuth detection system and the like described below,
It is extremely effective.

In this embodiment, the magnetic detection unit 8 is provided with the TMR element 2. However, the present invention is not limited to the TMR element 2. A similar configuration can be used even when a GMR element (giant magnetoresistive element) of the system is used.

FIGS. 6 and 7 show a second embodiment of the present invention.
It will be described based on. The same parts as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted (the same applies to each of the following embodiments).

In the magnetic sensing element 11 of the present embodiment, the fourth layer 7 functioning as a soft magnetic film for assisting magnetic field sensing is divided into a plurality (for example, six) as shown by fourth layers 7a to 7f. By arranging them in parallel, with respect to the magnetic detection unit 8,
The lower first layer 4 has an array-like configuration that intersects as one common electrode. The third layer 6 also has an array configuration corresponding to the fourth layer 7. As a result, each fourth layer 7
A TMR element is formed with the first layer 4 for each of a to 7f (each third layer).

As a manufacturing method, after forming the first layer 4 and the second layer 5 as in the case of the first embodiment, an Fe-Co50 film is formed by a sputtering method as in the above-described case. Further, the fourth layers 7a to 7f (also the third layers) are formed by a patterning process of forming a CoZrNb amorphous film and dividing the film into a plurality by a photolithography method.
It is produced by forming

In this case, as an example of the configuration of the detection circuit for the magnetic detection element 11, as shown in FIG. 7, the fourth layer 7a to 7f, which also function as electrodes, is located between the first layer 4 and the fourth layer 7a to 7f. While the DC power supply 13 is connected,
A micro ammeter 15 is connected to the layers 7a to 7f via a switching circuit 14, and the switching circuit 13
By the switching operation described above, magnetic changes in the fourth layers 7a to 7f are individually and reliably detected as changes in the MR ratio of the individual TMR elements for each of the detection points 12a to 12f.

Therefore, the magnetic sensing element 11 of the present embodiment
According to the method, since the detection points 12a to 12f are arranged in an array as a plurality of points, the same effects as those of the first embodiment can be obtained, and further, the use applications can be appropriately expanded. Be practical.

A third embodiment of the present invention will be described with reference to FIG. In the magnetic sensing element 21 of the present embodiment, the high magnetic permeability layer 22 is formed by a sputtering method, a CVD method, a plating method, or a sol-gel method by being positioned near the magnetic sensing unit 8, here, the TMR element 2. Things. Desirably, the magnetic permeability of such a high magnetic permeability layer 22 is 100 or more. Specifically, a CoZrNb film, NiCoFe
It is formed of a film, an FeNi film, or the like. Also, as a manufacturing method, a photolithography method, a mask deposition method, a bonding method, and the like can be used as appropriate. And such a high magnetic permeability layer 22 is the fourth
It is completed in a form electrically connected to the soft magnetic film for assisting magnetic field sensing of the layer 7.

According to the magnetic sensing element 21 of the present embodiment, since the high magnetic permeability layer 22 functions as a magnetic flux sink,
Further higher sensitivity can be achieved.

A fourth embodiment of the present invention will be described with reference to FIG. The magnetic sensing element 31 of the present embodiment has a Mn-Z layer on the high magnetic permeability layer 22 located near the magnetic sensing section 8.
An n ferrite block obtained by dicing is formed as a bulk type magnetic body 32. The bulk type magnetic body 32 is not limited to the one obtained by dicing a Mn-Zn ferrite block.

In general, it is known that a bulk type magnetic material can realize much lower magnetic permeability and coercivity than a magnetic thin film, and has a characteristic that it is hardly saturated because of a large amount of magnetic flux that can be handled. Therefore, according to the magnetic sensing element 31 of the present embodiment, the bulk magnetic body 32 is
By having it above, the sensitivity can be further improved.

It should be noted that the bulk type magnetic body 32 does not necessarily need to be formed on the high magnetic permeability layer 22, and it is only necessary that the bulk type magnetic body 32 be formed near the magnetic sensing unit 8.

A fifth embodiment of the present invention will be described with reference to FIG. In the magnetic sensing element 41 of the present embodiment, the fourth layer 42 as a soft magnetic film for assisting magnetic field sensing is formed of Ti, T
a, a plurality of soft magnetic layers (for example, a Co—Zr—Nb film, an Fe—Ni film) via a nonmagnetic layer (not shown) such as SiO _2.
, Etc.) are formed as a laminated structure.

According to the magnetic sensing element 41 of the present embodiment, the fourth layer (magnetic field sensing assisting soft magnetic film) 42 is formed as a laminated structure of a plurality of soft magnetic layers via a nonmagnetic layer. Can prevent the formation of a return magnetic domain,
Low noise and high frequency (that is, high-speed sampling) can be achieved, and the element function can be further improved.

A sixth embodiment of the present invention will be described with reference to FIG. In the magnetic sensing element 51 of the present embodiment, for example, the planar shape of the fourth layer 52 as a soft magnetic film for assisting magnetic field sensing such as a Co—Zr—Nb film or an Fe—Ni film is formed into an elliptical circular shape. It was done. The shape is not limited to the elliptical shape, and may be, for example, a perfect circle shape.

According to the magnetic sensing element 51 of the present embodiment, since the fourth layer (magnetic field sensing auxiliary soft magnetic film) 52 is formed in a circular shape, the magnetostatic energy can be further reduced. Therefore, the generation of magnetic charge is reduced,
Since the magnetic domain is stabilized, low noise can be realized. As a result, the sensitivity of the device can be increased.

A seventh embodiment of the present invention will be described with reference to FIG. The magnetic sensing element 61 of the present embodiment is formed by dividing a fourth layer 62 as a soft magnetic film for assisting magnetic field sensing into a plurality of portions 62a, 62b,. More specifically, for example, Fe-Ni
The fourth layer (soft magnetic film for assisting magnetic field sensing) 62 is
Portions 62a, 62 each having a size of about 5 μm × 0.5 μm
, 62n. Each part 62a, 62
When b,..., 62n have such a size, the generation of the return magnetic domain can be suppressed, and a substantially single magnetic domain configuration is obtained. As a result, noise can be reduced. At the same time, the anisotropy is easily aligned, and the sensitivity of the device can be increased.

It is to be noted that the present invention is not limited to the completely divided structure as shown in FIG. 12, but for example, a plurality of cuts 71a, 71b,
, 71n can suppress generation of return magnetic domains and reduce noise even in the case of a divided shape.

An eighth embodiment of the present invention will be described with reference to FIG. The magnetic sensing element 81 of the present embodiment is, for example, in addition to the magnetic sensing element 21 having the configuration shown in FIG.
As a reset magnetic field generating means for returning the magnetization state of each magnetic layer (the first layer 4, the third layer 6, the fourth layer 7, etc.) of the magnetic detection unit 8 to a predetermined state, here, an initial state. The reset current wiring portion 82 is formed by the magnetic sensing portion 8 and the high magnetic permeability layer 2.
2 is formed over the entire length in the vicinity of 2.

According to the magnetic sensing element 81 having such a configuration, for example, when it is detected that an abnormality has occurred in the measured value by using the azimuth detecting system described later,
A reset current is caused to flow through the reset current wiring portion 82, and each magnetic layer (the first layer 4, the third layer 6,
By returning the magnetization state of the fourth layer 7 and the like) to the initial state, it becomes possible to perform a normal detection operation thereafter. That is, the change of the operating point due to the magnetization of the TMR element 2 portion due to the temporary strong magnetic field can be canceled, and the device can function normally after the cancellation. The present invention is useful not only in the case of application to an azimuth detection system for detecting terrestrial magnetism described later but also in the case of application as a normal magnetic sensor.

The reset magnetic field generating means includes:
The present invention is not limited to the reset current wiring section 82 provided integrally on the element. For example, as shown in FIG. 15, an external coil 83 that generates a reset magnetic field by passing through the element 81 may be used. Good.

A ninth embodiment of the present invention will be described with reference to FIG. This embodiment shows an example of application to a azimuth detection system of geomagnetism detection using a magnetic detection element as in each of the above-described embodiments. First, for example, three magnetic sensing elements 91a, 91b, 91c (the above-described magnetic sensing elements 1, 11, 21, 31, 41, 51, 61, 7).
1, 81) may be provided independently in the direction of the xyz three-axis vector. These magnetic sensing elements 91a, 91b, 91
The detection output of c is input to a three-magnetic-component detection unit 94 as detection means via a data acquisition unit 93. The three-magnetic-component detecting unit 94 detects three-axis vector components based on detection outputs of the magnetic detecting elements 91a, 91b, and 91c with respect to geomagnetism detection. On the other hand, the magnetic sensing elements 91a, 91b, 91 captured via the data capturing section 93
an absolute value calculation unit 95 for calculating the absolute value of the detected output c, and a threshold value obtained by adding a measurement margin to a preset comparative geomagnetism intensity with a magnitude of the absolute value calculated by the absolute value calculation unit 95; An abnormality detecting means 97 is provided by a comparing section 96 for comparison. When the magnitude of the calculated absolute value exceeds the threshold, the comparing unit 96 determines that the detection result is abnormal. On the output side of the comparing section 96, there is provided an alarm section 98 as an informing means which operates based on the abnormality detection output.

Thus, according to the azimuth detecting system of the present embodiment, when a detection result having a magnitude exceeding a preset threshold is obtained by adding a measurement margin to the measured geomagnetic intensity. In this case, the fact that there is an abnormality in the measured value is notified through the alarm unit 98, so that use of an erroneous detection result can be prevented. More practically, a system configuration may be used in which the output of the alarm unit 98 is notified to the user of the system via the communication unit 99 by communication, together with the detection result obtained from the three magnetic component detection unit 94.

Further, in constructing the present system, if the magnetic sensing element 81 shown in FIGS. 14 and 15 is used as the three magnetic sensing elements 91a, 91b, 91c, the detection result by the comparing section 96 is obtained. When an abnormality is detected at the time, a reset current is passed by reset means (not shown) using the reset current wiring portion 82 or the external coil 83, thereby setting the magnetization state of the magnetic detection portion 8 to the initial state. If the reset is performed, the geomagnetic detection operation can be performed normally after the reset.

In the azimuth detecting system of the present embodiment, three magnetic detecting elements 91a, 91b and 91c are used. However, three or more magnetic detecting elements are independently arranged in directions of three or more axis vectors. The detection of the terrestrial magnetism direction may be performed as vector detection of three or more axes.

[0069]

According to the magnetic sensing element of the first aspect of the present invention, a tunnel magnetoresistive element (TMR element) or a giant magnetoresistive element (GMR element) originally manufactured by using a thin film technique or the like is used. As a result, the size and weight can be reduced, and the coercive force disposed on one surface of the element is lower than the coercive force of the magnetic layer, and the anisotropic axis of the magnetic layer is anisotropic. A magnetic field sensing auxiliary soft magnetic film set independently of the sex axis is provided, so that magnetic force detection can be performed by separating functions by utilizing the difference in coercive force, thereby improving the magnetic field sensitivity as a sensor be able to.

According to the second aspect of the present invention, in realizing the first aspect of the present invention, it is possible to easily form an array and to broaden its use.

According to the third aspect of the present invention, in the magnetic sensing element according to the first or second aspect, the high magnetic permeability layer connected to the soft magnetic film for assisting magnetic field sensing is provided in the vicinity of the magnetic sensing portion. The magnetic permeability layer functions as a magnetic flux sink, so that higher sensitivity can be achieved.

According to the invention set forth in claim 4, according to claim 1,
2. In the magnetic sensing element described in 2 or 3, a bulk magnetic material having characteristics that can realize a much lower magnetic permeability and coercivity than a magnetic thin film, and have a characteristic of being hardly saturated because of a large amount of magnetic flux that can be handled is provided near the magnetic sensing unit. Therefore, the sensitivity can be further improved.

According to the fifth aspect of the present invention, in the magnetic sensing element according to the third aspect, since the bulk magnetic material is provided on the high magnetic permeability layer near the magnetic sensing portion, the sensitivity is further improved. be able to.

According to the sixth aspect of the present invention, in order to realize the invention according to any one of the first to fifth aspects, a magnetic field sensing auxiliary is formed as a laminated structure of a plurality of soft magnetic layers on a nonmagnetic layer. Since the soft magnetic film is formed, it is possible to prevent the formation of the return magnetic domain, so that the noise can be reduced and the frequency can be increased (high-speed sampling), and the element performance can be further improved. Can be.

According to the seventh aspect of the present invention, in realizing the invention of any one of the first to sixth aspects, the soft magnetic film for assisting magnetic field sensing has a circular planar shape. Since the energy can be reduced, the generation of magnetic charge is reduced, and the stability of the magnetic domain can be expected. Therefore, the noise or the sensitivity can be reduced, and the element performance can be further improved.

According to the eighth aspect of the present invention, in order to realize any one of the first to sixth aspects of the present invention, the soft magnetic film for assisting magnetic field sensing is formed by being divided into a plurality of portions. Therefore, if the individual sizes are reduced, the generation of the return magnetic domain can be suppressed, the noise can be reduced, and further, the anisotropy can be made uniform and the sensitivity can be further improved.

According to the ninth aspect of the present invention, in order to realize the invention of any one of the first to sixth aspects, the soft magnetic film for assisting magnetic field sensing is formed in a plurality of cuts so as to be divided. Therefore, if the individual sizes are reduced, the generation of the return magnetic domain can be suppressed, the noise can be reduced, and the anisotropy can be made uniform to further increase the sensitivity.

According to the tenth aspect of the present invention, the first aspect
10. In the magnetic sensing element according to any one of claims 9 to 9, even in a case where an erroneous detection is performed due to a change in the operating point due to the magnetization of the magnetic sensing unit due to the influence of a temporary strong magnetic field, for example, , The magnetization state of the magnetic detection unit can be returned to a predetermined state, so that a normal detection operation can be performed thereafter.

According to the eleventh aspect of the present invention, the tenth aspect of the present invention can be easily realized by using the reset current wiring portion integrally formed near the magnetic sensing portion.

According to the twelfth aspect, the invention according to the tenth aspect can be easily realized by using an external coil for generating a reset magnetic field for the magnetic detection unit.

According to the azimuth detecting system of the thirteenth aspect, when the present invention is applied to an azimuth detecting system in which terrestrial magnetism is to be detected, basically, the heights independently arranged in directions of three or more axis vectors. A vector of three or more axes detected based on the detection output of the magnetic sensing element according to any one of claims 1 to 12 having high sensitivity is used. At this time, the absolute value of the detection output of the magnetic sensing element has been measured. It is determined whether or not there is an abnormality in the detection result by comparing with the threshold obtained by adding the measurement margin to the terrestrial magnetism intensity.If an abnormality is detected, this fact is notified, and an erroneous detection result Use can be prevented beforehand.

According to the azimuth detecting system of the fourteenth aspect of the present invention, it is basically the same as the thirteenth aspect of the present invention. By causing a reset current to flow through the generation means to reset the magnetization state of the magnetic detection unit to a predetermined state and resetting, the subsequent erroneous detection operation can be avoided.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a substrate on which a first layer is formed according to a first embodiment of the present invention.

FIGS. 2A and 2B show a pattern shape of a first layer, wherein FIG. 2A is a plan view and FIG.

3A and 3B show a pattern shape of a second layer formed on a first layer, wherein FIG. 3A is a plan view and FIG. 3B is a vertical sectional front view.

4A and 4B show a pattern shape of a third layer formed on a second layer, wherein FIG. 4A is a plan view and FIG. 4B is a vertical sectional front view.

5A and 5B show a pattern shape of a fourth layer formed on a third layer, wherein FIG. 5A is a plan view and FIG. 5B is a vertical sectional front view.

6A and 6B show a magnetic sensing element according to a second embodiment of the present invention, wherein FIG. 6A is a plan view and FIG. 6B is a longitudinal sectional front view.

FIG. 7 is a plan view showing a measurement circuit.

8A and 8B show a magnetic sensing element according to a third embodiment of the present invention, wherein FIG. 8A is a plan view and FIG. 8B is a longitudinal sectional front view.

9A and 9B show a magnetic sensing element according to a fourth embodiment of the present invention, where FIG. 9A is a plan view and FIG. 9B is a longitudinal sectional front view.

FIGS. 10A and 10B show a magnetic sensing element according to a fifth embodiment of the present invention, wherein FIG. 10A is a plan view and FIG.

FIG. 11 is a plan view showing a magnetic sensing element according to a sixth embodiment of the present invention.

FIG. 12 is a plan view showing a magnetic sensing element according to a seventh embodiment of the present invention.

FIG. 13 is a plan view showing a magnetic sensing element according to a modified example.

FIG. 14 is a plan view showing a magnetic sensing element according to an eighth embodiment of the present invention.

FIG. 15 is a plan view showing a magnetic sensing element of a modified example.

FIG. 16 is a schematic system configuration diagram showing an azimuth detecting system according to a ninth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic sensing element 2 Tunneling magnetic effect resistance element 3 Magnetic layer 7 Soft magnetic film for assisting magnetic field sensing 8 Magnetic sensing unit 11 Magnetic sensing element 21 Magnetic sensing element 22 High permeability layer 31 Magnetic sensing element 32 Bulk magnetic material 41 Magnetic sensing Element 42 Soft magnetic film for assisting magnetic field sensing 51 Magnetic sensing element 52 Soft magnetic film for assisting magnetic field sensing 61 Magnetic sensing element 62 Soft magnetic film for assisting magnetic field sensing 62a, 62b, ..., 62n Part 71 Magnetic sensing element 72 For assisting magnetic field sensing Soft magnetic films 72 a, 72 b,..., 72 n Notches 81 Magnetic sensing element 91 Magnetic sensing element 94 Detecting means 97 Abnormality detecting means 98 Reporting means

Claims (14)

[Claims] 1. A flat-plate-type magnetic sensor in which a tunneling magnetoresistive element or a giant magnetoresistive element having a magnetic layer is used, and a magnetic detecting unit detects magnetism by passing a current in a direction perpendicular to the film surface. An element, wherein the coercive force disposed on one surface of the element is lower than the coercive force of the magnetic layer, and the anisotropic axis thereof is set independently of the anisotropic axis of the magnetic layer. A magnetic sensing element comprising a soft magnetic film for assisting magnetic field sensing. 2. The magnetic field sensing assisting soft magnetic film is formed on the magnetic sensing portion as a plurality of magnetic films individually in an array, and the magnetic layer intersects with the plurality of magnetic films. The magnetic sensing element according to claim 1, wherein the magnetic sensing element is formed as a common electrode. 3. The magnetic sensing element according to claim 1, wherein a high magnetic permeability layer is provided near the magnetic sensing portion and connected to the soft magnetic film for assisting magnetic field sensing. 4. The magnetic sensing element according to claim 1, wherein a bulk type magnetic body is arranged near the magnetic sensing portion. 5. The magnetic sensing element according to claim 3, wherein a bulk magnetic body is disposed on the high magnetic permeability layer. 6. The magnetic field sensing auxiliary soft magnetic film according to claim 1, wherein the soft magnetic film is formed as a laminated structure of a plurality of soft magnetic layers on the non-magnetic layer. Magnetic sensing element. 7. The soft magnetic film for assisting magnetic field sensing has a circular planar shape.
7. A magnetic sensing element according to any one of claims 6 to 6. 8. The magnetic sensing element according to claim 1, wherein the soft magnetic film for assisting magnetic field sensing is formed by being divided into a plurality of portions. 9. The magnetic sensing element according to claim 1, wherein a plurality of cuts are formed in the soft magnetic film for assisting magnetic field sensing. 10. The magnetic sensing element according to claim 1, further comprising reset magnetic field generating means for returning a magnetization state of the magnetic sensing unit to a predetermined state. 11. The magnetic sensing element according to claim 10, wherein the reset magnetic field generating means includes a reset current wiring unit integrally formed near the magnetic sensing unit. 12. The magnetic sensing element according to claim 10, wherein said reset magnetic field generating means includes an external coil for generating a reset magnetic field for said magnetic sensing unit. 13. A plurality of magnetic sensing elements according to any one of claims 1 to 12, which are independently arranged in directions of three or more axis vectors and detect terrestrial magnetism, and detection outputs of these magnetic sensing elements. Detecting means for detecting a vector of three or more axes based on the above, and abnormality detecting means for determining whether there is an abnormality in the detection result based on an absolute value of the detection output of the magnetic sensing element and a preset threshold value; And a notifying means for notifying that the abnormality is detected by the abnormality detecting means. 14. A plurality of magnetic sensing elements according to claim 10, 11 or 12, which are independently arranged in directions of three or more axis vectors to detect terrestrial magnetism, and based on detection outputs of these magnetic sensing elements. Detecting means for detecting a vector of three or more axes, abnormality detecting means for determining whether or not the detection result is abnormal based on an absolute value of the detection output of the magnetic detecting element and a preset threshold value; Notification means for notifying that the abnormality has been detected by the abnormality detection means; and resetting the magnetization state of the magnetic detection unit to a predetermined state when the abnormality detection means has detected the abnormality. A reset means for causing a reset current to flow through the magnetic field generating means.