JP4285695B2 - Thin film magnetic sensor and rotation sensor - Google Patents

Description

  The present invention relates to a thin film magnetic sensor and a rotation sensor, and more specifically, a rotation sensor capable of detecting a rotation angle of a rotating external magnetic field, or a rotation angle and a rotation direction, and a thin film magnetic used in such a rotation sensor. It relates to sensors.

  A magnetic sensor is an electromagnetic force (eg, current, voltage, power, magnetic field, magnetic flux, etc.), a mechanical quantity (eg, position, velocity, acceleration, displacement, distance, tension, pressure, torque, temperature, humidity, etc.), An electronic device that converts a detected amount such as a biochemical amount into a voltage via a magnetic field. Magnetic sensors are classified into Hall sensors, anisotropic magnetoresistive (AMR) sensors, giant magnetoresistive (GMR) sensors, etc., depending on the magnetic field detection method.

Among these, GMR sensors are
(1) The maximum value of the change rate of the electrical resistivity (that is, the MR ratio (= Δρ / ρ ₀ )) is extremely large as compared with the Hall sensor or the AMR sensor.
(2) The temperature change of the electrical resistance value is small compared to the Hall sensor.
(3) Since the material having a giant magnetoresistance effect is a thin film material, it is suitable for microfabrication.
There are advantages such as. Therefore, the GMR sensor is expected to be applied as a high-sensitivity micromagnetic sensor used in computers, electric power, automobiles, home appliances, portable devices and the like.

As a material showing the GMR effect,
(1) A multilayer film of a ferromagnetic layer (eg, permalloy) and a nonmagnetic layer (eg, Cu, Ag, Au, etc.), or an antiferromagnetic layer, a ferromagnetic layer (fixed layer), a nonmagnetic layer, and a strong layer A metal artificial lattice composed of a multilayer film (so-called “spin valve”) having a four-layer structure of a magnetic layer (free layer),
(2) a metal-metal nanogranular material comprising nm-sized fine particles made of a ferromagnetic metal (eg, permalloy) and a grain boundary phase made of a nonmagnetic metal (eg, Cu, Ag, Au, etc.),
(3) a tunnel junction film in which an MR effect is generated by a spin-dependent tunnel effect;
(4) a metal-insulator nano-granular material comprising nanometer-sized ferromagnetic metal alloy fine particles and a grain boundary phase made of a nonmagnetic / insulating material,
Etc. are known.

  Among these, a multilayer film represented by a spin valve is generally characterized by high sensitivity in a low magnetic field. However, the multilayer film needs to be laminated with high accuracy with thin films made of various materials, so that the stability and yield are poor, and there is a limit in suppressing the manufacturing cost. For this reason, this type of multilayer film is used only for high value-added devices (for example, magnetic heads for hard disks), and is applied to magnetic sensors that are forced to compete with AMR sensors and Hall sensors with low unit prices. Is considered difficult. In addition, the diffusion between the multilayer films is likely to occur due to the temperature, and the GMR effect is easily lost.

On the other hand, nano-granular materials are generally easy to produce and have good reproducibility. Therefore, if this is applied to a magnetic sensor, the cost of the magnetic sensor can be reduced. In particular, metal-insulator nanogranular materials
(1) If the composition is optimized, a high MR ratio exceeding 10% is exhibited at room temperature.
(2) Since the electrical resistivity is an order of magnitude higher, the power consumption of the magnetic sensor can be reduced.
(3) Unlike spin valve films including antiferromagnetic films with poor heat resistance, they can be used in high-temperature environments.
There are advantages such as. However, since the metal-insulator nanogranular material exhibits an MR ratio of several percent under a giant magnetic field of ˜kOe or more, there is a problem that the magnetic field sensitivity in a low magnetic field (100 Oe or less) is very small.

In order to solve this problem, Patent Document 1 describes that a soft magnetic thin film is disposed at both ends of a giant magnetoresistive thin film to increase the magnetic field sensitivity of the giant magnetoresistive thin film. In the same document, a permalloy thin film (soft magnetic film) having a thickness of 2 μm is formed on a substrate, a gap of about 9 μm in width is formed on the permalloy thin film using an ion beam etching apparatus, and Co _{38 is formed} in the gap portion. _A method of manufacturing a thin film magnetic sensor in which a nano granular GMR film (Co—Y—O nano granular GMR film) having a composition of _.6 Y _14.0 O _47.4 is stacked is described.

  In Patent Document 2, in order to further improve magnetic field sensitivity in a thin film magnetoresistive element in which soft magnetic thin films are arranged at both ends of a giant magnetoresistive thin film, the thickness of the giant magnetoresistive thin film is set to the thickness of the soft magnetic thin film. The following points are described.

Claim 1 and paragraph number “0019” of JP-A-11-087804 Claim 1 of JP-A-11-274599

  A soft magnetic material having a large saturation magnetization and a high magnetic permeability has a very high magnetic field sensitivity and exhibits a very large magnetization in a relatively weak external magnetic field. For this reason, a thin film (GMR film) having a large electric resistance and a giant magnetoresistance effect is arranged in a narrow gap sandwiched between thin film yokes made of soft magnetic material so as to be electrically connected to the thin film yoke. When an external magnetic field is applied to the thin film magnetic sensor, the thin film yoke is magnetized by the weak external magnetic field, and a strong magnetic field 100 to 10,000 times the external magnetic field is applied to the GMR film. As a result, the magnetic field sensitivity of the GMR film can be significantly increased. A metal-insulator granular thin film is currently known as the GMR film.

  Further, as described in Patent Document 2, if the thickness of the GMR film is made thinner than the thickness of the thin film yoke, the magnetic flux leaking from the thin film yoke is suppressed from being dispersed in the film thickness direction. Magnetic field sensitivity can be further improved.

Thin film magnetic sensors have a variety of uses and applications, and are generally designed with the idea of increasing sensitivity to obtain a high output voltage with a lower magnetic field. That is, in order to increase the sensitivity to an external magnetic field applied in the gap length direction, it is common in the art to make the yoke length L in the gap length direction larger than the yoke width maximum value W _{max in the} direction perpendicular to the gap length. . Nevertheless, as long as the thin-film yoke has a finite size, the minimum saturation magnetic field of the thin-film yoke is at most 1 to 5 (Oe).

Therefore, in applications such as an electronic compass where the orientation is examined while detecting 0.5 (Oe) _max , the magnetic field is operated with a magnetic field smaller than the minimum saturation magnetic field of the thin film yoke. It is easy to obtain a sine wave (cosine wave) output with respect to the geomagnetic direction using a range with good linearity. Therefore, it is easy to obtain a highly accurate rotation sensor by dividing the waveform equally with respect to the angle.

  On the other hand, rotation angle detection magnetic sensors used in industrial robots, automobiles, machine tools, and the like are relatively large in the order of several tens (Oe) to several hundreds (Oe) in order to reduce the influence of disturbance and magnetic noise. In general, a magnetic field is applied to a thin film magnetic sensor in parallel. In this case, the magnetic field as a signal source is equal to or several times larger than the minimum saturation magnetic field of the thin film magnetic sensor. This is because the output voltage is maintained substantially constant even when the distance (mounting accuracy) between the magnetic field generation source, which is a signal source, and the thin film magnetic sensor varies.

  In other words, when trying to operate with a magnetic field smaller than the minimum saturation magnetic field of the thin film magnetic sensor, the applied magnetic field fluctuates with a slight change in the distance between the magnetic field generation source and the thin film magnetic sensor, and the output from the thin film magnetic sensor is large. This is because fluctuations occur, resulting in major problems such as an increase in adjustment cost and a decrease in yield.

  However, in the conventional thin film magnetic sensor, the output waveform corresponding to the rotation angle of the parallel uniform magnetic field becomes an isolated wave, and if the waveform is divided into a triangular wave or sine wave / cosine wave output that enables high-precision angle resolution, There wasn't. Therefore, in order to accurately calculate the rotation angle of the magnetic field from the output voltage, there is a problem that complicated calculation is required. In addition, this causes a problem that the calculation speed is delayed or the calculation circuit is expensive.

  The problem to be solved by the present invention is that in a simplest rotation sensor system in which a relatively large external magnetic field of about several tens (Oe) to several hundreds (Oe) is uniformly applied to a thin film magnetic sensor unit. An object of the present invention is to provide a thin film magnetic sensor in which the output of the thin film magnetic sensor according to the rotation angle of the external magnetic field is a triangular wave, sine wave or cosine wave output, and a rotation sensor using the same.

As a result of reexamining the principle and structure of the thin film magnetic sensor again in order to solve the above problems, the present invention has been achieved. A thin film magnetic sensor according to the present invention is made of a soft magnetic material and is formed between a pair of thin film yokes opposed to each other through a gap and the gap so as to be electrically connected to the pair of thin film yokes. And a GMR film having a higher electrical resistivity than the soft magnetic material, and the thin film yoke and an insulating substrate made of an insulating / nonmagnetic material that supports the GMR film, wherein the thin film yoke has a different gap length direction. Between the isotropic magnetic field H _k (x) and the anisotropic magnetic field H _k (y) perpendicular to the gap length,
H _k (x) ≧ H _k (y)
It is summarized that there is a relationship represented by

  The gist of the rotation sensor according to the present invention is that it includes the thin film magnetic sensor according to the present invention.

When the anisotropic magnetic field H _k (x) in the gap length direction of the thin film yoke is relatively increased, the magnetic field sensitivity in the direction perpendicular to the gap length is increased. Therefore, when a relatively large external magnetic field of several tens to several hundreds (Oe) from the oblique direction with respect to the gap length direction is actuated, the thin film yoke is magnetized according to the incident angle of the external magnetic field, and a triangular wave or sine wave output A voltage is obtained. Further, this makes it possible to divide the waveform equally with respect to the angle, so that a highly accurate rotation sensor can be obtained.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIGS. 1A and 1B are a plan view and a front view, respectively, of the thin film magnetic sensor 20 according to the first embodiment of the present invention.

  In FIG. 1, the thin film magnetic sensor 20 is electrically connected to an insulating substrate (not shown), a pair of thin film yokes 24, 24 opposed via a gap 24a, and the pair of thin film yokes 24, 24. Thus, a GMR film 26 formed between the gaps 24a is provided. The GMR film 26 is disposed symmetrically with respect to the center of the gap 24a. Further, an electrode (not shown) for taking out the output is joined to the rear ends (end portions not facing the gap 24a) of the respective thin film yokes 24, 24. Further, a protective film (not shown) made of an insulating / nonmagnetic material is usually formed on the thin film yokes 24, 24 and the GMR film 26 to shield and protect them from the atmosphere.

  First, the insulating substrate will be described. The insulating substrate is for supporting the thin-film yokes 24 and 24 and the GMR film 26, and is made of an insulating / nonmagnetic material. Specifically, the material of the insulating substrate is glass or high-rigidity material such as alumina whose surface is smoothed by a sputtered film, Si with thermal oxide film, alumina with insulating film such as alumina, ceramics such as titanium carbide, etc. Is a suitable example.

  The shape of the insulating substrate is not particularly limited, and an optimal shape may be selected in accordance with the use of the thin film magnetic sensor 20, required characteristics, and the like.

  Next, the thin film yokes 24 and 24 will be described. The thin film yokes 24 and 24 are for increasing the magnetic field sensitivity of the GMR film 26 and are made of a soft magnetic material. In order to obtain high magnetic field sensitivity to a weak magnetic field, it is preferable to use a material having a high magnetic permeability μ and / or saturation magnetization Ms for the thin film yokes 24 and 24. Specifically, the magnetic permeability μ is preferably 100 or more, and more preferably 1000 or more. The saturation magnetic field Ms is preferably 5 (kGauss) or more, and more preferably 10 (kGauss) or more.

Specifically, the materials of the thin film yokes 24, 24 are permalloy (40 to 90% Ni—Fe alloy), sendust (Fe ₇₄ Si ₉ Al ₁₇ ), hard palm (Fe ₁₂ Ni ₈₂ Nb ₆ ), Co ₈₈ Nb ₆ Zr ₆ amorphous alloy, (Co ₉₄ Fe ₆ ) ₇₀ Si ₁₅ B ₁₅ amorphous alloy, Finemet (Fe _75.6 Si _13.2 B _8.5 Nb _1.9 Cu _0.8 ), Nanomax (Fe ₈₃ Hf ₆ C ₁₁ ), Fe ₈₅ Zr ₁₀ B ₅ alloy, Fe ₉₃ Si ₃ N ₄ alloy, Fe ₇₁ B ₁₁ N ₁₈ alloy, Fe _71.3 Nd _9.6 O _19.1 nano granular alloy, Co ₇₀ Al ₁₀ Preferred examples include O ₂₀ nanogranular alloy, Co ₆₅ Fe ₅ Al ₁₀ O ₂₀ alloy, and the like.

Next, the GMR film 26 will be described. The GMR film 26 is for detecting a change in the external magnetic field as a change in voltage, and is made of a material having a giant magnetoresistance effect. In order to detect the change of the external magnetic field with high sensitivity, Δρ / ρ ₀ (Δρ = ρ _H −ρ ₀ : ρ _H of the GMR film 26 is the electric resistivity in the magnetic field H, and ρ ₀ is the magnetic field zero. The absolute value of the MR ratio defined as (electrical resistivity) is preferably 5% or more, more preferably 10% or more.

In the present invention, since the GMR film 26 is directly electrically connected to the thin film yokes 24 and 24, the GMR film 26 having a higher electrical resistivity than the thin film magnetic yokes 24 and 24 is used. In general, in the case of a material having an electric resistivity that is too small, the thin film yokes 24 and 24 are electrically short-circuited, which is not preferable. On the other hand, in the case of a material having an electrical resistivity that is too high, it is difficult to detect a change in the external magnetic field as a voltage change. The electrical specific resistance of the GMR film 26 is preferably 10 ³ μΩcm or more and 10 ¹² μΩcm or less, and more preferably 10 ⁴ μΩcm or more and 10 ¹¹ μΩcm or less.

  There are various materials that satisfy such conditions, and among them, the above-described metal-insulator nanogranular material is particularly suitable. A metal-insulator nanogranular material not only has a high MR ratio and a high electrical resistivity, but also has a characteristic that does not fluctuate greatly due to slight composition fluctuations. In addition, there is an advantage that it can be manufactured at a low cost.

Specific examples of the metal-insulator nanogranular material having a giant magnetoresistance effect used as the GMR film 26 include a Co—Y ₂ O ₃ nanogranular alloy, a Co—Al ₂ O ₃ nanogranular alloy, and Co—Sm _2. O ₃ based nano granular alloy, _Co-Dy 2 _{O 3} system nano granular alloy, _FeCo-Y 2 _{O 3} system nano granular _{alloy, Fe-MgF 2, FeCo-} MgF 2, Fe-CaF 2, (Fe, Co, Ni) - ( Fluoride nanogranular alloys such as MgF ₂ , CaF ₂ , SrF ₂ ) and the like are preferable examples.

  Next, the shapes of the thin film yokes 24 and 24 and the GMR film 26 will be described. In order to change the magnetization strength of the thin-film yokes 24, 24 to a triangular wave shape or a sine wave shape in accordance with the inclination angle of the external magnetic field when an external magnetic field acts obliquely with respect to the gap length direction, a thin film The yokes 24 and 24 and the GMR film 26 desirably satisfy the following conditions.

First, the thin-film yokes 24 and 24 include at least an anisotropic magnetic field H _k (x) in the gap length direction (hereinafter referred to as “x direction”) and a direction perpendicular to the gap length direction (hereinafter referred to as “y direction”). It is necessary to have a relationship represented by the following equation (1) with the anisotropic magnetic field H _k (y).
H _k (x) ≧ H _k (y) (1)

The anisotropic magnetic field H _k is the minimum external magnetic field strength H required to saturate the magnetic flux density B inside the magnetic material. That is, “small anisotropy magnetic field H _k ” means that the magnetization of the magnetic material is saturated with a smaller external magnetic field H (that is, the magnetic field sensitivity is high). If the anisotropic magnetic field H _k (y) in the y direction is made relatively small (that is, the magnetic field sensitivity is made relatively high), an external magnetic field acts from an oblique direction with respect to the x direction. However, the thin film yokes 24 and 24 are relatively strongly magnetized. As a result, the strength of magnetization of the thin-film yokes 24 and 24 changes in a triangular wave shape or a sine wave shape in accordance with the inclination angle of the external magnetic field.

Second, the thin film yokes 24 and 24 have a relationship expressed by the following equation (2) between the length L in the x direction, the average value W _{ave of the} width, and the average value t _ave of the thickness. The thing which has is preferable.
(W _ave × t _ave ) / L ² ≧ (L × t _ave ) / W _ave ² (2)
Here, the “average width W _ave ” refers to a value obtained by dividing the integral value of the width W in the length L direction (that is, the plane area of the thin film yoke) by the length L. The “average thickness t _ave ” refers to a value obtained by dividing the integral value of the thickness t in the L direction (that is, the cross-sectional area of the thin film yoke) by the length L.

Expression (2) can be obtained as follows. That is, it is known that the anisotropic magnetic field H _k generally has a relationship represented by the following equation (3) between the demagnetizing field coefficient N _d .
H _x = N _d · 4πI _s (3)
However, I _s is the strength of the saturation magnetization.

On the other hand, the demagnetizing factor N _d of the cylindrical magnetic body is generally known to be expressed by the following equation (4).
N _d = (1 / k ² ) (log _e 2k−1) (4)
However, k represents the ratio (size ratio = L / a) of the length (L) to the diameter (a) of the magnetic material.
From the equation (4), the following relational equation (5) can be approximated.
N _d = (a ² / L ² ) (log ₂ (L / a) −1) to a ² / L ² = πa ² / πL ²
~ Cross sectional area / (length) ² × (1 / π) (5)

Therefore, the following relational expression (6) is obtained from the expressions (1), (3) and (5).
x-direction cross-sectional area / (length) ² ≧ y-direction cross-sectional area / (length) ² (6)
When the length in the x direction of the thin film yokes 24, 24 is L, the average value of the width viewed from the x direction is W _ave , and the average value of the thickness is t _ave , the cross-sectional area and the length in the x direction are respectively (W _ave × t _ave ) and L, and the cross-sectional area and length in the y direction are (L × t _ave ) and W _ave , respectively, and if this is substituted into equation (6), (2 ) Formula is obtained.

Equation (2) represents one of the specific methods for making the anisotropic magnetic field H _k (x) in the x direction equal to or greater than the anisotropic magnetic field H _k (y) in the y direction. That is, when the length, width, and thickness of the thin film yokes 24 and 24 are determined so as to satisfy the relationship of the expression (2), the magnetization strength of the thin film yokes 24 and 24 is determined according to the inclination angle of the external magnetic field. It means that it can be changed into a triangular wave shape or a sine wave shape. In the formula (2), the shape of the thin-film yokes 24 and 24 does not necessarily have a symmetric shape. As long as the relationship of the formula (2) is satisfied, any shape such as a polygonal shape or a circular shape can be used. It may mean that it may have.

Thirdly, the thickness t _f of the tips of the thin film yokes 24 and 24 (the side in contact with the GMR film 26), the width W _f of the tips of the thin film yokes 24 and 24, and the width W _g of the GMR film 26. There is a relationship represented by the following equation (7) between the smaller one (in the present invention, this is expressed as “min (t _f , W _f , W _g )”) and the gap length GL. Is desirable.
min (t _f , W _f , W _g ) ≦ GL (7)

  Even when the pair of thin film yokes 24 and 24 satisfy the first condition described above, if the gap length GL (that is, the length of the GMR film 26) is relatively short, the right and left thin films The yokes 24, 24 operate as pseudo integrated yokes and are easily magnetized in the gap length direction. If the gap length GL is relatively short, a triangular wave or sine wave output cannot be obtained.

On the other hand, if t _f ≦ GL, the left and right thin film yokes 24 and 24g are unlikely to operate as a pseudo-integrated yoke, so that a triangular or sinusoidal output can be easily obtained. The thin-film magnetic sensor 20, because it is fabricated by laminating thin films, it is _{generally, t f <W g ≦ W} f. However, it is also possible to satisfy t _f > W _f (or W _g ) by increasing the film thickness. In this case, if W _f (or W _g ) ≦ GL, the left and right thin-film yokes can be prevented from operating as a pseudo integrated yoke.

Fourth, the width _{W g} of the GMR film 26 is desirably less yoke width _{W f} of the tip of the thin film yokes 24b and 24c.
The lateral width W _g of the GMR film 26 may exceed the yoke width W _f at the tips of the thin film yokes 24, 24. However, if the width _{W g} of the GMR film 26 is greater than the yoke width _{W f} of the thin film yokes 24b and 24c tip, it increases the GMR film region that is sensitive to weak magnetic flux leaking from the thin film yokes 24b and 24c in the lateral direction, a comprehensive Magnetic field sensitivity decreases.
Therefore, when high magnetic field sensitivity is required, the ratio (W _g / W _f ) of the lateral width W _g of the GMR film 26 to the yoke width W _f at the tips of the thin film yokes 24, 24 is preferably 1.0 or less. .

Fifth, the thickness t _g of the GMR film 26 is preferably equal to or less than the thickness t _f of the tips of the thin film yokes 24, 24.
The thickness t _g of the GMR film 26 may exceed the thickness t _f of the tips of the thin film yokes 24, 24. However, when the thickness _{t g} of the GMR film 26 is greater than the thickness _{t f} of the thin film yokes 24b and 24c tip, increases the GMR film region that is sensitive to weak magnetic flux leaking in the thickness direction from the thin film yokes 24b and 24c, total Magnetic field sensitivity is reduced.
Therefore, when high magnetic field sensitivity is required, the ratio (t _g / t _f ) of the thickness t _g of the GMR film 26 to the thickness t _f of the tips of the thin film yokes 24, 24 is 1.0 or less. preferable.

In the thin film magnetic sensor 20 shown in FIG. 1, the thin film yokes 24 and 24 have a rectangular shape having a length L, a width W _r , and a thickness t, and the width W _r and the thickness t are uniform regardless of the location. In addition, the width W _r is larger than the length L. Therefore, the thin film yokes 24 and 24 shown in FIG. 1 satisfy the first and second conditions.

The length of the GMR film 26 (i.e., the gap length GL) is a thin film yokes 24b and 24c tip is larger than the thickness _{t f,} it satisfies the third condition. Further, the lateral width (W _g ) of the GMR film 26 is narrower than the lateral width (W _f ) of the tips of the thin film yokes 24, 24, and the thickness t _g of the GMR film 26 is the thickness of the tips of the thin film yokes 24, 24. It is thinner than t _f (= t), and satisfies the above-described fourth and fifth conditions.

  1 shows a state in which the end surfaces of the thin film yokes 24, 24 on the gap 24a side are perpendicular to the bottom surfaces of the thin film yokes 24, 24 (or the surface of an insulating substrate (not shown)). This is merely an example, and as long as the electrical contact state with the thin film yokes 24, 24 can be stably obtained, the end surface of the thin film yokes 24, 24 on the gap 24a side is in a plane perpendicular to the surface of the insulating substrate. It may be inclined. However, in order to obtain high magnetic field sensitivity, the end faces of the thin film yokes 24, 24 on the gap 24a side are preferably perpendicular to the surface of the insulating substrate.

  In FIG. 1B, the GMR film 26 whose cross-sectional shape is rectangular is illustrated, but this is merely an example, and the electrical contact state with the thin film yokes 24 and 24 is stable. As long as it is obtained, the cross-sectional shape of the GMR film 26 may not be rectangular.

  Next, a thin film magnetic sensor according to a second embodiment of the invention will be described. 2A and 2B are a plan view and a front view of the thin film magnetic sensor 40 according to the present embodiment, respectively.

  In FIG. 2, the thin film magnetic sensor 40 is electrically connected to an insulating substrate (not shown), a pair of thin film yokes 44 and 44 opposed via a gap 44a, and the pair of thin film yokes 44 and 44. Thus, a GMR film 46 formed between the gaps 44a is provided. Further, an electrode (not shown) for taking out the output is joined to the rear ends (end portions not facing the gap 44a) of the respective thin film yokes 44, 44. Further, a protective film (not shown) made of an insulating / nonmagnetic material is usually formed on the thin film yokes 44 and 44 and the GMR film 46 to shield and protect them from the atmosphere.

In the present embodiment, the thin film yokes 44 and 44 have a trapezoidal shape in which the lateral width (W _f ) at the front end is narrower than the lateral width (W _r ) at the rear end. The average value W _ave (= (W _f + W _r ) / 2) of the widths of the thin film yokes 44, 44 is larger than the length L in the gap length direction, and satisfies the first and second conditions described above. Yes.

In this case, the lateral width (W _f ) of the tips of the thin-film yokes 44, 44 is not particularly limited, but if the lateral width (W _f ) of the tips is too small, the sensitivity in the gap length direction is relatively increased. Therefore, it is not preferable. Accordingly, the lateral width of the tips of the thin film yokes 44, 44 is preferably 1/3 or more of the length L in the gap length direction, more preferably 1/2 or more.

Further, the gap length GL of the GMR film 46, the leading end of the thin film yokes 44 and 44 is larger than the thickness _{t f,} satisfies the third condition mentioned above.
Further, the width (W _g ) of the GMR film 46 is equal to the lateral width (W _f ) of the tips of the thin film yokes 44 and 44, and satisfies the above-described fourth condition.
Further, the sectional shape of the thin film yokes 44 and 44 is substantially rectangular, the thickness t _f of the tip in contact with the GMR film 46 is slightly thinner than the thickness t _r of the rear end. Further, the thickness t _g of the GMR film 46 is thinner than the thickness t _f of the tips of the thin film yokes 44 and 44, and satisfies the above-mentioned fifth condition.

  The other points of the thin film yokes 44 and 44 and the GMR film 46, and the insulating substrate, electrode and protective film (not shown) are the thin film yokes 24 and 24 and the GMR film 26 according to the first embodiment, respectively. In addition, since it is similar to the insulating substrate, the electrode, and the protective film, the description is omitted.

  Next, a method for manufacturing a thin film magnetic sensor according to the present invention will be described. The thin film magnetic sensor 20 (40) according to the present invention can be manufactured using a normal thin film lamination technique. That is, first, a thin film made of a soft magnetic material is deposited on the surface of the insulating substrate, and thin film yokes 24 and 24 (44, 44) having a shape that satisfies the above-described conditions are formed by etching. Next, by masking except for the vicinity of the gap 24a (44a), depositing the GMR film 26 (46), and further forming an electrode and a protective film, the thin film magnetic sensor 20 (40) according to the present invention is obtained.

  Alternatively, a thin film made of a material having a giant magnetoresistance effect is deposited on the surface of the insulating substrate, and the GMR film 26 (46) having a predetermined width is formed by etching. Next, a thin film made of a soft magnetic material is deposited on both sides of the GMR film 26 (46) to form thin film yokes 24, 24 (44, 44) having a shape satisfying the above-described conditions by etching, and further, electrodes and protection When the film is formed, the thin film sensor 20 (40) according to the present invention is obtained.

Next, the operation of the thin film magnetic sensor according to the present invention will be described. In the conventional thin film magnetic sensor, the thin film yoke formed on both ends of the GMR film has a shape in which the length L in the x direction is larger than the maximum value W _{max of the} width. Even in a thin film magnetic sensor having such a structure, if a rotating magnetic field that is uniform and parallel to the thin film magnetic sensor and is equal to or more than the minimum saturation magnetic field of the thin film magnetic sensor acts, The output waveform according to the can be obtained.

  However, in the case of such a conventional thin film yoke, since the magnetic field sensitivity in the x direction is too high, the external output hardly changes even if the rotation angle of the rotating magnetic field is slightly changed, and the rotation angle is as high as about 90 °. A large output change appears when the angle is reached. As a result, the output waveform becomes an isolated wave.

On the other hand, if the shape of the thin-film yoke is determined so that the anisotropic magnetic field H _k (x) in the x direction is greater than or equal to the anisotropic magnetic field H _k (y) in the y direction, the sensitivity in the x direction is moderate. Therefore, when the external magnetic field is tilted from the x direction, the magnetic field corresponding to the rotation angle reaches the GMR film. As a result, an output waveform close to a triangular wave or a sine wave is obtained. In particular, when the anisotropic magnetic field H _k (x) in the x direction is substantially equal to the external magnetic field, a triangular or sinusoidal output waveform is easily obtained. Therefore, the rotation angle of the external magnetic field can be calculated with high accuracy by simple mathematical processing. Therefore, if the thin film magnetic sensor according to the present invention is used, the rotation sensor with a simple structure and low cost and high accuracy. Is obtained.

  Next, the rotation sensor according to the present invention will be described. The above-described thin film magnetic sensor according to the present invention can be used as a highly accurate rotation sensor as it is in an environment where the ambient temperature is constant. That is, if a constant current source is connected to both ends of the thin film magnetic sensor and a change in its output (voltage) is detected, the tilt angle of the magnetic field can be detected with high accuracy.

  However, the electrical resistance value of the GMR film varies greatly depending not only on the strength of the external magnetic field but also on the temperature. For this reason, when the rotation sensor including only the above-described thin film magnetic sensor is used in an environment where the ambient temperature varies, it is difficult to detect the tilt angle of the magnetic field with high accuracy because the reference potential varies. In addition, a rotation sensor using only a single thin film magnetic sensor has a limit in the magnitude of the output obtained, and it is difficult to detect the rotation direction of the external magnetic field.

  Therefore, in such a case, it is preferable to use one thin film magnetic sensor in combination with a reference resistor and / or another thin film magnetic sensor. Specifically, the following configuration is preferable.

  FIG. 3A shows a first specific example. A rotation sensor 50 shown in FIG. 3A includes a thin film magnetic sensor 52 according to the present invention and a reference resistor 54 connected in series to the thin film magnetic sensor 52. The reference resistor 54 has a function of compensating for a change in electrical resistance caused by a temperature change of the thin film magnetic sensor 52, and the absolute value of the electrical resistance value and the temperature coefficient are substantially equivalent to those of the thin film magnetic sensor 52. Used. Further, a power source (not shown) capable of applying a constant external voltage V (V) is connected to both ends of the rotation sensor 50, and the output terminal 56 is connected to a connection portion between the thin film magnetic sensor 52 and the reference resistor 54. Is provided.

  When a constant external voltage of V (V) is applied to both ends of the rotation sensor 50 shown in FIG. 3A, when an external magnetic field does not act, an output of about V / 2 (V) is output from the output terminal 56. Is obtained. On the other hand, when an external magnetic field acts on the rotation sensor 50, the resistance value of the GMR film changes according to the tilt angle, so that the output voltage varies. Moreover, since the reference resistor 54 is connected, even if the ambient temperature fluctuates, the output change due to the temperature change is canceled by the reference resistor 54. For this reason, only an output change corresponding to the rotation angle of the external magnetic field can be obtained from the output terminal 56.

  FIG. 3B shows a second specific example. The rotation sensor 60 shown in FIG. 3B includes a first thin film magnetic sensor 62a according to the present invention and a second thin film magnetic sensor according to the present invention connected in series to the first thin film magnetic sensor 62a. 62b. The second thin film magnetic sensor 62b is arranged such that the gap length direction is perpendicular to the gap length of the first thin film magnetic sensor 62a. Further, a power source (not shown) capable of applying a constant external voltage V (V) is connected to both ends of the rotation sensor 60, and the output terminal 66 is connected to the first thin film magnetic sensor 62a and the second thin film magnetic. It is provided at the connection portion of the sensor 62b.

  In other words, the rotation sensor 60 uses the second thin film magnetic sensor 62b instead of the reference resistor 54 in the rotation sensor 50 shown in FIG. The first thin film magnetic sensor 62a and the second thin film magnetic sensor 62b do not necessarily have the same configuration, but can detect the rotation angle of the external magnetic field with high accuracy regardless of the variation in the ambient temperature. For this purpose, the second thin film magnetic sensor 62b preferably has the same configuration as the first thin film magnetic sensor 62a.

  When a constant external voltage of V (V) is applied to both ends of the rotation sensor 60 shown in FIG. 3B, when an external magnetic field does not act, an output of about V / 2 (V) is output from the output terminal 66. Is obtained.

  On the other hand, when an external magnetic field acts on the rotation sensor 60, the electrical resistance values of the GMR film of the first thin film magnetic sensor 62a and the GMR film of the second thin film magnetic sensor 62b change according to the tilt angle. In addition, since the first thin film magnetic sensor 62a and the second thin film magnetic sensor 62b are connected in series so that the gap length directions are perpendicular to each other, the output change caused by the rotation of the external magnetic field is shown in FIG. This is about twice that of the rotation sensor 50 shown in FIG.

  Furthermore, since the second thin film magnetic sensor 62b also functions as a reference resistance for the first thin film magnetic sensor 62a, output changes due to changes in ambient temperature are offset. Therefore, only an output change corresponding to the rotation angle of the external magnetic field can be obtained from the output terminal 66.

  FIG. 3C shows a third specific example. The rotation sensor 70 shown in FIG. 3 (c) includes a first thin film magnetic sensor 72a according to the present invention, a first reference resistor 74a, a second thin film magnetic sensor 72b according to the present invention, and a second reference. A bridge circuit is configured using the resistor 74b.

The second thin film magnetic sensor 72b is arranged so that one end thereof is connected to one end of the first thin film magnetic sensor 72a and the gap length direction is perpendicular to the gap length of the first thin film magnetic sensor 72a. ing. The first reference resistor 74a has a function of compensating for an output change caused by a temperature change of the first thin film magnetic sensor 72a. One end of the first reference resistor 74a is connected to the other end of the first thin film magnetic sensor 72a. Yes. The second reference resistor 74 b is one having a function of compensating for output variations caused by temperature changes of the second thin film magnetic sensor 72b, one end is connected to the other end of the second thin film magnetic sensor 72b The other end is connected to the other end of the first reference resistor 74a.

Further, the connection portion of the first thin-film magnetic sensor 72a and the second thin film magnetic sensor 72b, and between the connection portion of the first reference resistor 7 4 a and the second reference resistor 7 4 b, the constant A power supply (not shown) to which an external voltage V (V) can be applied is connected. Further, output terminals 76a and 76b are connected to the connection portion of the first thin film magnetic sensor 72a and the first reference resistor 74a and the connection portion of the second thin film magnetic sensor 72b and the second reference resistor 74b, respectively. Is provided.

  In this case, each of the first reference resistor 74a and the second reference resistor 74b has an absolute value and a temperature coefficient that are substantially the same as those of the first thin film magnetic sensor 72a and the second thin film magnetic sensor 72b, respectively. Those that are equivalent are used. Further, the first thin film magnetic sensor 72a and the second thin film magnetic sensor 72b do not necessarily have the same configuration, but the rotation angle of the external magnetic field can be set with high accuracy regardless of the variation in the ambient temperature. In order to detect, it is preferable that the second thin film magnetic sensor 72b has the same configuration as the first thin film magnetic sensor 72a.

  When a constant external voltage of V (V) is applied on the diagonal line of the rotation sensor 70 shown in FIG. 3C, when the external magnetic field does not act, the output terminals 76a and 76b receive about V / V, respectively. An output of 2 (V) is obtained. Therefore, when the difference is taken, the output is about 0 (V).

  On the other hand, when an external magnetic field acts on the rotation sensor 70, the electrical resistance values of the GMR film of the first thin film magnetic sensor 72a and the GMR film of the second thin film magnetic sensor 72b change according to the tilt angle. In addition, since the reference resistors 74a and 74b are connected to the first thin film magnetic sensor 72a and the second thin film magnetic sensor 72b, respectively, even if the ambient temperature fluctuates, the output change caused by the temperature change occurs. Offset. Therefore, only the output change corresponding to the rotation angle of the external magnetic field can be obtained from the output terminals 76a and 76b.

  Since the first thin film magnetic sensor 72a and the second thin film magnetic sensor 72b are connected in series with the reference resistors 74a and 74b, respectively, the outputs obtained from the output terminals 76a and 76b are shown in FIG. This is equivalent to the rotation sensor 50 shown in a). However, the first thin film magnetic sensor 72a and the second thin film magnetic sensor 72b are connected so that their gap length directions are perpendicular to each other, and the difference between the output voltages obtained from the output terminals 76a and 76b is taken. Therefore, the output change due to the rotation of the external magnetic field is about twice that of the rotation sensor 50 shown in FIG.

  FIG. 3D shows a fourth specific example. A rotation sensor 80 shown in FIG. 3 (d) includes a first thin film magnetic sensor 82a, a second thin film magnetic sensor 82b, a third thin film magnetic sensor 82c, and a fourth thin film magnetic sensor 82d according to the present invention. Are used to construct a bridge circuit.

  That is, the rotation sensor 80 is the same as the rotation sensor 70 shown in FIG. 3C, but instead of the first reference resistor 74a and the second reference resistor 74b, the third thin film magnetic sensor 82c and the fourth thin film, respectively. The magnetic sensor 82d is used. The third thin film magnetic sensor 82c is arranged such that the gap length direction is perpendicular to the gap length direction of the first thin film magnetic sensor 82a. The fourth thin film magnetic sensor 82d is arranged such that the gap length direction is perpendicular to the gap length of the second thin film magnetic sensor 82b.

  In this case, the first to fourth thin film magnetic sensors 82a to 82d do not necessarily have the same configuration, but detect the rotation angle of the external magnetic field with high accuracy regardless of the variation in the ambient temperature. Therefore, it is preferable that the first to fourth thin film magnetic sensors 82a to 82d have the same configuration.

  Furthermore, there is a constant external voltage between the connection portion of the first thin film magnetic sensor 82a and the second thin film magnetic sensor 82b and between the connection portion of the third thin film magnetic sensor 82c and the fourth thin film magnetic sensor 82d. A power source (not shown) capable of applying V (V) is connected. Further, a connection portion between the first thin film magnetic sensor 82a and the third thin film magnetic sensor 82c and a connection portion between the second thin film magnetic sensor 82b and the fourth thin film magnetic sensor 82d are respectively connected to the output terminals 86a and 86a. 86b is provided.

  When a constant external voltage of V (V) is applied on the diagonal line of the rotation sensor 80 shown in FIG. 3D, when the external magnetic field does not act, the output terminals 86a and 86b receive about V / V, respectively. An output of 2 (V) is obtained. Therefore, when the difference is taken, the output is about 0 (V).

  On the other hand, when an external magnetic field acts on the rotation sensor 80, the electrical resistance values of the first to fourth thin film magnetic sensors 82a to 82d change according to the inclination angle. In addition, since the third thin film magnetic sensor 82c and the fourth thin film magnetic sensor 82d function as reference resistances for the first thin film magnetic sensor 82a and the second thin film magnetic sensor 82b, respectively, the ambient temperature varies. However, the output change due to the temperature change is canceled out. For this reason, only output changes corresponding to the rotation angle of the external magnetic field can be obtained from the output terminals 86a and 86b.

  Further, since the first thin film magnetic sensor 82a and the third thin film magnetic sensor 82c are connected in series so that the gap length directions are perpendicular to each other, the output obtained from the output terminal 86a is as shown in FIG. The rotation sensor 50 shown in FIG. Similarly, since the second thin film magnetic sensor 82b and the fourth thin film magnetic sensor 82d are connected in series so that the gap length directions thereof are perpendicular to each other, the output obtained from the output terminal 86b is as shown in FIG. The rotation sensor 50 shown in FIG. Further, the first thin film magnetic sensor 82a and the second thin film magnetic sensor 82b are connected so that the gap length directions thereof are perpendicular to each other, and take the difference between the output voltages obtained from the output terminals 86a and 86b. Therefore, the output change due to the rotation of the external magnetic field is about four times that of the rotation sensor 50 shown in FIG.

  Furthermore, since the midpoint voltage output (phase I) from the output terminal 86a and the midpoint voltage output (phase II) from the output terminal 86b have exactly 90 ° different output waveforms, the difference between the two is obtained. By taking this, it is possible to distinguish whether the rotation direction of the external magnetic field is clockwise (CW) or counterclockwise (CCW). Furthermore, the rotation angle can be detected with higher accuracy by comparing the output values of the two (so-called Lissajous waveform).

A soft magnetic thin film made of amorphous ((Co ₉₄ Fe ₆ ) ₈₂ Si ₉ B ₉ , magnetic permeability μ = 5000, saturation magnetization Ms = 13 (kGauss)), and FeCo-MgF on an insulating substrate made of alkali-free glass A thin film magnetic sensor 20 having the shape shown in FIG. 1 was manufactured by laminating _two GMR films in a predetermined order and finely processing them. The soft magnetic thin film had a thickness of 1.0 μm and a gap length of 1.5 μm. Each thin film yoke 24, 24 has a length L in the gap length direction of 140 μm and a width W in the direction perpendicular to the gap length of 400 μm.

In this embodiment, the lateral width (W _g ) of the GMR film 26 is 50 μm, and the film thickness (t _g ) is 0.5 μm. Furthermore, electrodes were formed at the ends of the thin film yokes 24, 24, and a protective film was further formed on the surface thereof to obtain the thin film magnetic sensor 20. In this example, the anisotropic magnetic field H _k (x) in the x direction was 50 (Oe), and the anisotropic magnetic field H _k (y) in the y direction was 10 (Oe).

(Comparative Example 1)
A thin film magnetic sensor was fabricated according to the same procedure as in Example 1 except that the shape of the thin film yoke was changed to a gap length length L = 500 μm and a width W perpendicular to the gap length W = 200 μm. In the case of Comparative Example 1, the anisotropic magnetic field H _k (x) in the x direction was 10 (Oe). The anisotropic magnetic field H _k (y) in the y direction was 40 (Oe).

  The two thin film magnetic sensors obtained in Example 1 were arranged so that their gap length directions were perpendicular to each other, and these were connected in series to obtain a rotation sensor (see FIG. 4A). ). Similarly, a rotation sensor was obtained using the two thin film magnetic sensors obtained in Comparative Example 1 (see FIG. 4B). Further, while applying a voltage to the obtained rotation sensor, a rotating magnetic field of 100 (Oe) rotating in a plane where the sensor was arranged was applied, and a change in the midpoint voltage due to a change in magnetoresistance was measured.

FIG. 5 shows the relationship between the rotation angle of the external magnetic field and the midpoint voltage. In FIG. 5, the vertical axis represents the ratio of the midpoint voltage to the maximum value. FIG. 5 also shows an ideal output waveform (double sine) obtained by this type of rotation sensor. From FIG. 5, it can be seen that the output waveform of the rotation sensor of Comparative Example 1 is an isolated wave, whereas the rotation sensor of Example 1 has a substantially triangular wave output waveform. This is because the magnetic sensitivity in the y direction is improved by relatively increasing the anisotropic magnetic field H _k (x) in the x direction.

A thin film magnetic sensor and a rotation sensor were produced according to the same procedure as in Example 1 except that the gap length was 2.5 μm. In this example, the anisotropic magnetic field H _k (x) in the x direction was 50 (Oe), and the anisotropic magnetic field H _k (y) in the y direction was 10 (Oe). A rotating magnetic field was applied to the obtained rotation sensor under the same conditions as in Example 1, and changes in the midpoint voltage due to changes in magnetoresistance were measured.

  FIG. 6 shows the relationship between the rotation angle of the external magnetic field and the midpoint voltage. FIG. 6 also shows an ideal output waveform (double sine) and the output waveform obtained in Comparative Example 1. From FIG. 6, it can be seen that by increasing the gap length GL from 1.5 μm to 2.5 μm, the output waveform is slightly closer to a sine wave from the triangular wave, and becomes a better waveform. This is presumably because the interference between the left and right thin film yokes was reduced by increasing the gap length GL, and the magnetic field sensitivity in the y direction was improved.

In accordance with the same procedure as in Example 1, a thin film magnetic sensor 40 having the shape shown in FIG. However, in this embodiment, the yoke thickness was 1.5 μm and the gap length GL was 2.5 μm. Each thin-film yoke 44, 44 has a length L in the gap length direction of 140 μm, a front end width W _f (= W _g ) = 200 μm, and a rear end width W _r = 600 μm. In the present example, the anisotropic magnetic field H _k (x) in the x direction was 65 (Oe), and the anisotropic magnetic field H _k (y) in the y direction was 6 (Oe).

  Further, in the same manner as in Example 1, the obtained two thin film magnetic sensors were respectively arranged so that the gap length directions thereof were perpendicular to each other, and these were connected in series to obtain a rotation sensor. A rotation magnetic field of 100 (Oe) was applied to the obtained rotation sensor, and a change in the midpoint voltage due to a change in magnetoresistance was measured.

FIG. 7 shows the relationship between the rotation angle of the external magnetic field and the midpoint voltage. FIG. 7 also shows an ideal output waveform (double sine) and the output waveform obtained in Comparative Example 1. From FIG. 7, it can be seen that if the shape of the thin-film yoke is trapezoidal with the gap length GL being 2.5 μm, the output waveform is closer to a sine wave from the triangular wave and becomes a favorable waveform. This is because by making the shape of the thin film yoke trapezoidal, the anisotropic magnetic field H _k (x) in the x direction is further increased, and the magnetic field sensitivity in the y direction is improved.

  The embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.

  For example, when a rotation sensor is configured using two or more thin film magnetic sensors, the rotation sensor may be manufactured by individually manufacturing a thin film magnetic sensor and pasting the thin film magnetic sensor on an appropriate substrate. Alternatively, two or more thin film magnetic sensors may be simultaneously formed on the same substrate so as to satisfy a predetermined positional relationship and used as a rotation sensor.

  The rotation sensor according to the present invention detects rotation information of automobile axles, rotary encoders, industrial gears, etc., stroke position of hydraulic / pneumatic cylinders, detection of position / speed information of machine tool slides, etc. It can be used for detection of current information such as arc current of a welding robot.

FIG. 1A is a plan view of a thin film magnetic sensor according to the first embodiment of the present invention, and FIG. 1B is a front view thereof. FIG. 2A is a plan view of a thin film magnetic sensor according to the second embodiment of the present invention, and FIG. 2B is a front view thereof. It is a schematic block diagram of the rotation sensor which concerns on one embodiment of this invention. 4A is a schematic configuration diagram of the rotation sensor manufactured in Example 1, and FIG. 4B is a schematic configuration diagram of the rotation sensor manufactured in Comparative Example 1. It is a figure which shows the relationship between the rotation angle of an external magnetic field measured about the rotation sensor obtained in Example 1 and Comparative Example 1, and a midpoint voltage. It is a figure which shows the relationship between the rotation angle of an external magnetic field measured about the rotation sensor obtained in Example 2 and Comparative Example 1, and a midpoint voltage. It is a figure which shows the relationship between the rotation angle of an external magnetic field measured about the rotation sensor obtained in Example 3 and Comparative Example 1, and a midpoint voltage.

Explanation of symbols

20, 40 Thin film magnetic sensor 24, 44 Thin film yoke 24a, 44a Gap 26, 46 GMR film 50, 60, 70, 80 Rotation sensor 52, 62a, 62b, 72a, 72b, 82a-82d Thin film magnetic sensor 54, 74a, 74b Reference resistor 56, 66, 76a, 76b, 86a, 86b Output terminal

Claims (8)

A pair of thin film yokes made of a soft magnetic material and opposed to each other through a gap;
A GMR film formed between the gaps so as to be electrically connected to the pair of thin film yokes and having a higher electrical resistivity than the soft magnetic material;
An insulating substrate made of an insulating / nonmagnetic material that supports the thin film yoke and the GMR film;
The thin film yoke has an anisotropic magnetic field H _k (x) in the gap length direction and an anisotropic magnetic field H _k (y) in the direction perpendicular to the gap length,
H _k (x) ≧ H _k (y)
A thin film magnetic sensor with the relationship represented by The thin film yoke has a length L in the gap length direction, an average value W _{ave of} width, and an average value t _{ave of} thickness,
(W _ave × t _ave ) / L ² ≧ (L × t _ave ) / W _ave ²
The thin film magnetic sensor according to claim 1, wherein there is a relationship represented by: The thin film yoke has a thickness t _f at the tip, a width W _f at the tip, or a width W _g of the GMR film, which is smaller (min (t _f , W _f , W _g )). ) And the gap length GL,
min (t _f , W _f , W _g ) ≦ GL
The thin film magnetic sensor according to claim 1, wherein there is a relationship represented by:   A rotation sensor comprising the thin film magnetic sensor according to claim 1. The first thin film magnetic sensor according to any one of claims 1 to 3,
A first reference resistor connected in series to the first thin film magnetic sensor and having a function of compensating for an electric resistance change caused by a temperature change of the first thin film magnetic sensor;
A rotation sensor comprising: an output terminal provided at a connection portion between the first thin film magnetic sensor and the first reference resistor. The first reference resistor comprises the second thin film magnetic sensor according to any one of claims 1 to 3,
6. The rotation sensor according to claim 5, wherein the second thin film magnetic sensor is arranged so that a gap length direction thereof is perpendicular to a gap length direction of the first thin film magnetic sensor. The first thin film magnetic sensor according to any one of claims 1 to 3,
4. One end of the first thin film magnetic sensor is connected to one end of the first thin film magnetic sensor, and the gap length direction of the first thin film magnetic sensor is perpendicular to the gap length direction of the first thin film magnetic sensor. A second thin film magnetic sensor according to any one of the above,
A first reference resistor having one end connected to the other end of the first thin film magnetic sensor and having a function of compensating for an electric resistance change caused by a temperature change of the first thin film magnetic sensor;
One end of the second thin film magnetic sensor is connected to the other end of the second thin film magnetic sensor, the other end is connected to the other end of the first reference resistor, and the resistance change due to the temperature change of the second thin film magnetic sensor. A second reference resistor having a function of compensating for
A rotation provided with a connection portion between the first thin film magnetic sensor and the first reference resistor, and an output terminal provided at a connection portion between the second thin film magnetic sensor and the second reference resistance. Sensor. The first reference resistor comprises the third thin film magnetic sensor according to any one of claims 1 to 3,
The third thin film magnetic sensor is arranged such that the gap length direction is perpendicular to the gap length direction of the first thin film magnetic sensor,
The second reference resistor comprises the fourth thin film magnetic sensor according to any one of claims 1 to 3,
The rotation sensor according to claim 7, wherein the fourth thin film magnetic sensor is arranged so that a gap length thereof is perpendicular to a gap length of the second thin film magnetic sensor.

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