JPH05145143A - Magnetoresistance element and measuring method for magnetic field strength - Google Patents
Magnetoresistance element and measuring method for magnetic field strengthInfo
- Publication number
- JPH05145143A JPH05145143A JP3307673A JP30767391A JPH05145143A JP H05145143 A JPH05145143 A JP H05145143A JP 3307673 A JP3307673 A JP 3307673A JP 30767391 A JP30767391 A JP 30767391A JP H05145143 A JPH05145143 A JP H05145143A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- magnetoresistive element
- soft magnetic
- conductor
- magnetic body
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims description 5
- 239000004020 conductor Substances 0.000 claims abstract description 15
- 239000000696 magnetic material Substances 0.000 claims description 15
- 239000000463 material Substances 0.000 claims description 5
- 229910045601 alloy Inorganic materials 0.000 abstract description 7
- 239000000956 alloy Substances 0.000 abstract description 7
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 abstract description 5
- 239000003302 ferromagnetic material Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 229910003266 NiCo Inorganic materials 0.000 description 1
- 238000011088 calibration curve Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、磁気センサなどに用い
られる磁気抵抗素子および磁場強度測定法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element used in a magnetic sensor and the like and a magnetic field strength measuring method.
【０００２】[0002]
【従来の技術】従来、磁気抵抗素子としては、強磁性体
の磁気抵抗効果を利用した素子が多く使用されてきた。
従来の磁気抵抗素子の一例を図３に示す。磁気抵抗素子
は強磁性体からなる磁気抵抗素子部１１とその両端の一
対の電極部１２から構成される。磁気抵抗効果は、強磁
性体の抵抗Ｒが強磁性体の磁化方向と強磁性体に流す電
流方向との間の角度θによって、 Ｒ＝Ｒ0 ＋ΔＲ・ｃｏｓ2 θ と変化する現象である。ここに、Ｒ0 は磁化方向が電流
方向と垂直になった場合の抵抗、ΔＲは磁化方向と電流
方向が平行になった場合の抵抗とＲ0 との差である。磁
気抵抗素子のＳ／Ｎ比はΔＲ／Ｒ0 で表される。図４に
従来、磁気抵抗素子に用いられてきた強磁性体であるＮ
ｉＦｅ合金における抵抗率の磁場依存性を示す。Ｒ0 ，
ΔＲに対応する抵抗率をそれぞれρ0 ，Δρとすると、
ΔＲ／Ｒ０＝Δρ／ρ０は（２０．８−２０）／２０＝
０．０４となる。その他の強磁性体であるＮｉＣｏ，Ｎ
ｉＣｕ合金などでもΔρ／ρ0 はいずれも室温で数％程
度であり、磁場センサなどに用いるにはＳ／Ｎ比は不十
分であった。以上、強磁性体の磁気抵抗効果を利用した
磁気抵抗素子はＳ／Ｎ比が非常に低いという問題点があ
った。2. Description of the Related Art Conventionally, as a magnetoresistive element, an element utilizing the magnetoresistive effect of a ferromagnetic material has been widely used.
An example of a conventional magnetoresistive element is shown in FIG. The magnetoresistive element is composed of a magnetoresistive element part 11 made of a ferromagnetic material and a pair of electrode parts 12 at both ends thereof. The magnetoresistive effect is a phenomenon in which the resistance R of the ferromagnetic material changes to R = R 0 + ΔR · cos 2 θ depending on the angle θ between the magnetization direction of the ferromagnetic material and the direction of the current flowing in the ferromagnetic material. Here, R 0 is the resistance when the magnetization direction is perpendicular to the current direction, and ΔR is the difference between R 0 and the resistance when the magnetization direction is parallel to the current direction. The S / N ratio of the magnetoresistive element is represented by ΔR / R 0 . FIG. 4 shows N, which is a ferromagnetic material that has been conventionally used in a magnetoresistive element.
The magnetic field dependence of the resistivity in an iFe alloy is shown. R 0 ,
If the resistivities corresponding to ΔR are ρ 0 and Δρ, respectively,
ΔR / R 0 = Δρ / ρ 0 is (20.8-20) / 20 =
It becomes 0.04. Other ferromagnetic materials such as NiCo and N
In the iCu alloy and the like, Δρ / ρ 0 is about several% at room temperature, and the S / N ratio is insufficient for use in a magnetic field sensor or the like. As described above, the magnetoresistive element utilizing the magnetoresistive effect of the ferromagnetic material has a problem that the S / N ratio is extremely low.
【０００３】[0003]
【発明が解決しようとする課題】本発明の目的は、従来
の磁気抵抗素子の問題であったＳ／Ｎ比の低さを解決
し、Ｓ／Ｎ比の高い磁気抵抗素子を提供することおよび
この磁気抵抗素子を用いた磁場強度測定法を提供するこ
とにある。SUMMARY OF THE INVENTION An object of the present invention is to solve the problem of the conventional magnetoresistive element, that is, the low S / N ratio, and to provide a magnetoresistive element having a high S / N ratio. It is to provide a magnetic field strength measuring method using this magnetoresistive element.
【０００４】[0004]
【課題を解決するための手段】このような目的を達成す
るために、本発明の磁気抵抗素子は、一対の電極を両端
に有する導体表面に、軟磁性体が直接設けられているこ
とを特徴とする。In order to achieve such an object, the magnetoresistive element of the present invention is characterized in that a soft magnetic material is directly provided on a conductor surface having a pair of electrodes at both ends. And
【０００５】また、本発明の磁気抵抗素子は、一対の電
極を両端に有する導体表面に、非磁性体を介して軟磁性
体が設けられていることを特徴とする。Further, the magnetoresistive element of the present invention is characterized in that a soft magnetic material is provided on a conductor surface having a pair of electrodes at both ends via a nonmagnetic material.
【０００６】さらにまた、本発明の磁場強度測定法は、
導体表面に直接または非磁性体を介して軟磁性体が設け
られている磁気抵抗素子を磁場中に配置して該磁気抵抗
素子の両端に高周波を印加し、該磁気抵抗素子の高周波
抵抗値の磁場による変化に基づいて磁場の強度を測定す
ることを特徴とする。Furthermore, the magnetic field strength measuring method of the present invention is
A magnetoresistive element in which a soft magnetic material is provided on the surface of a conductor directly or via a nonmagnetic material is placed in a magnetic field, and a high frequency is applied to both ends of the magnetoresistive element. It is characterized in that the strength of the magnetic field is measured based on the change due to the magnetic field.
【０００７】[0007]
【作用】本発明においては、磁気抵抗素子の高周波抵抗
の磁場依存性が大きいことを利用する。その結果、高い
Ｓ／Ｎ比で磁場を測定することができる。In the present invention, the fact that the high frequency resistance of the magnetoresistive element is highly dependent on the magnetic field is utilized. As a result, the magnetic field can be measured with a high S / N ratio.
【０００８】[0008]
【実施例】以下、図面を参照しつつ本発明の実施例を詳
細に説明する。Embodiments of the present invention will now be described in detail with reference to the drawings.
【０００９】図１は本発明の実施例を示す斜視図であ
り、一対の電極４を有する導体２からなるラインの上下
に、軟磁性体１が設けられた構造を成している。３は磁
気抵抗素子部、５は外部磁場である。このような構造を
持つ素子の両端にある周波数ｆを印加した時の抵抗Ｒ
（ｆ）は、 Ｒ（ｆ）＝Ｒ0 （ｆ）＋ΔＲmag （ｆ） で表される。ここで、Ｒ0 （ｆ）は軟磁性体が積層され
ていない導体のみの場合の抵抗、ΔＲmag （ｆ）は軟磁
性体が設けられたことによる抵抗の増加分である。Ｒ0
（ｆ）は周波数が１ＧＨｚ以下では、ほとんど周波数に
依存せず一定値となる。一方、軟磁性体では、高周波域
で比透磁率の虚数部μ″（ｆ）が大きくなり、 ΔＲmag （ｆ）∝ｆ・μ″（ｆ） の関係により、ΔＲmag （ｆ）は大きくなる。軟磁性体
に外部磁場を印加していくと、μ″（ｆ）は徐々に小さ
くなり、印加磁場の大きさが軟磁性体の異方性磁場に比
べ十分大きな値となると遂にはμ″（ｆ）は零となる。
従って、図１に示した磁気抵抗素子のＳ／Ｎ比は、 ΔＲmag （ｆ）／Ｒ0 （ｆ） で表されることになる。Ｒ0 （ｆ）は小さく、ΔＲmag
（ｆ）は高周波域で非常に大きな値となるため、この磁
気抵抗素子は非常に大きなＳ／Ｎ比を持つことになる。FIG. 1 is a perspective view showing an embodiment of the present invention, in which a soft magnetic material 1 is provided above and below a line consisting of a conductor 2 having a pair of electrodes 4. Reference numeral 3 is a magnetoresistive element portion, and 5 is an external magnetic field. Resistance R when a frequency f is applied to both ends of an element having such a structure
(F) is represented by R (f) = R 0 (f) + ΔR mag (f). Here, R 0 (f) is the resistance only in the case where the soft magnetic material is not laminated, and ΔR mag (f) is the increase in resistance due to the provision of the soft magnetic material. R 0
When the frequency is 1 GHz or less, (f) has a constant value that is almost independent of the frequency. On the other hand, in the soft magnetic material, the imaginary part μ ″ (f) of the relative permeability increases in the high frequency range, and ΔR mag (f) increases due to the relationship ΔR mag (f) ∝f · μ ″ (f). .. When an external magnetic field is applied to the soft magnetic material, μ ″ (f) gradually decreases, and when the magnitude of the applied magnetic field becomes sufficiently larger than the anisotropic magnetic field of the soft magnetic material, finally μ ″ (f f) becomes zero.
Therefore, the S / N ratio of the magnetoresistive element shown in FIG. 1 is represented by ΔR mag (f) / R 0 (f). R 0 (f) is small and ΔR mag
Since (f) has a very large value in a high frequency range, this magnetoresistive element has a very large S / N ratio.
【００１０】導体２として膜厚１μｍのＣｕを、軟磁性
体１として膜厚０．５μｍのＮｉＦｅ合金を使用し、周
波数５００ＭＨｚにおいて測定した抵抗の外部磁場依存
性を図２に示す。磁気抵抗素子部の長さは８ｍｍ、幅は
１．５ｍｍである。抵抗値は外部磁場零の時４．７０Ω
であるが、外部磁場の増加と共に急激に低下し、ＮｉＦ
ｅ合金の異方性磁場５ Ｏｅより十分大きな外部磁場下
では、０．６９５Ωにまで低下する。この実験では、Ｒ
0 ＝０．６９５Ω、ΔＲmag ＝４．７０−０．６９５≒
４．０であり、Ｓ／Ｎ比はΔＲmag ／Ｒ0 ≒４．０／
０．６９５≒５．７６と非常に高い値となる。FIG. 2 shows the external magnetic field dependence of the resistance measured at a frequency of 500 MHz using Cu having a film thickness of 1 μm as the conductor 2 and NiFe alloy having a film thickness of 0.5 μm as the soft magnetic body 1. The magnetoresistive element portion has a length of 8 mm and a width of 1.5 mm. Resistance value is 4.70Ω when external magnetic field is zero
However, it decreases sharply with an increase in the external magnetic field, and NiF
Under an external magnetic field sufficiently larger than the anisotropic magnetic field 5 Oe of the e-alloy, the value drops to 0.695Ω. In this experiment, R
0 = 0.695Ω, ΔR mag = 4.70−0.695≈
4.0, and the S / N ratio is ΔR mag / R 0 ≈4.0 /
It is a very high value of 0.695≈5.76.
【００１１】なお、本発明による磁気抵抗素子では、Ｃ
ｕおよびＮｉＦｅ合金の膜厚を厚くすることにより、Ｒ
0 を下げ、ΔＲmag を上げることができるため、これら
の膜厚を適当に設定することにより、Ｓ／Ｎ比をさらに
向上させることが可能である。In the magnetoresistive element according to the present invention, C
By increasing the film thickness of u and NiFe alloy, R
Since 0 can be decreased and ΔR mag can be increased, it is possible to further improve the S / N ratio by appropriately setting these film thicknesses.
【００１２】この結果から明らかなように、本発明の磁
気抵抗素子は従来の磁気抵抗素子に比べ、Ｓ／Ｎ比が高
いという利点がある。As is clear from this result, the magnetoresistive element of the present invention has an advantage that the S / N ratio is higher than that of the conventional magnetoresistive element.
【００１３】図２に示したように、磁気抵抗素子の両端
に高周波を印加した時、抵抗値は外部磁場に大きく依存
する。従って、あらかじめ較正曲線を求めておけば、抵
抗値から外部磁場の強度を求めることができる。As shown in FIG. 2, when a high frequency is applied across the magnetoresistive element, the resistance value greatly depends on the external magnetic field. Therefore, if the calibration curve is obtained in advance, the strength of the external magnetic field can be obtained from the resistance value.
【００１４】なお、図１において軟磁性体１は、導体２
の表面に直接接触して設けられているが、他の実施例と
して、軟磁性体を導体表面に非磁性体を介して設けた磁
気抵抗素子も、図１の磁気抵抗素子と同様に高いＳ／Ｎ
比を持つ磁気抵抗素子として機能する。In FIG. 1, the soft magnetic material 1 is the conductor 2.
However, as another embodiment, a magnetoresistive element in which a soft magnetic material is provided on a conductor surface via a nonmagnetic material has a high S value as in the magnetoresistive element of FIG. / N
It functions as a magnetoresistive element having a ratio.
【００１５】[0015]
【発明の効果】以上説明したように、本発明による磁気
抵抗素子は高周波抵抗が大きな磁場依存性を示すため磁
気抵抗素子としてのＳ／Ｎ比が非常に高いという利点が
ある。As described above, the magnetoresistive element according to the present invention has an advantage that the S / N ratio as the magnetoresistive element is very high because the high frequency resistance exhibits a large magnetic field dependency.
【図１】本発明の磁気抵抗素子の一実施例を示す斜視図
である。FIG. 1 is a perspective view showing an embodiment of a magnetoresistive element of the present invention.
【図２】本発明の磁気抵抗素子における抵抗の磁場依存
性の一例を示す特性図である。FIG. 2 is a characteristic diagram showing an example of magnetic field dependence of resistance in the magnetoresistive element of the present invention.
【図３】従来の磁気抵抗素子を示す斜視図である。FIG. 3 is a perspective view showing a conventional magnetoresistive element.
【図４】従来の磁気抵抗素子に使用されているＮｉＦｅ
膜における抵抗率の磁場依存性を示す特性図である。FIG. 4 NiFe used in a conventional magnetoresistive element
It is a characteristic view which shows the magnetic field dependence of the resistivity in a film.
１ 軟磁性体 ２ 導体 ３ 磁気抵抗素子部 ４ 電極 ５ 外部磁場 1 Soft Magnetic Material 2 Conductor 3 Magnetoresistive Element Section 4 Electrode 5 External Magnetic Field
Claims (3)
軟磁性体が直接設けられていることを特徴とする磁気抵
抗素子。1. A conductor surface having a pair of electrodes at both ends,
A magnetoresistive element characterized in that a soft magnetic material is directly provided.
非磁性体を介して軟磁性体が設けられていることを特徴
とする磁気抵抗素子。2. A conductor surface having a pair of electrodes at both ends,
A magnetoresistive element characterized in that a soft magnetic material is provided via a nonmagnetic material.
軟磁性体が設けられている磁気抵抗素子を磁場中に配置
して該磁気抵抗素子の両端に高周波を印加し、該磁気抵
抗素子の高周波抵抗値の磁場による変化に基づいて磁場
の強度を測定することを特徴とする磁場強度測定法。3. A magnetoresistive element in which a soft magnetic material is provided on the surface of a conductor directly or via a nonmagnetic material is arranged in a magnetic field, and a high frequency is applied to both ends of the magnetoresistive element. A magnetic field strength measuring method characterized in that the strength of the magnetic field is measured based on a change in the high frequency resistance value of the magnetic field due to the magnetic field.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3307673A JP2642268B2 (en) | 1991-11-22 | 1991-11-22 | Magnetic field strength measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3307673A JP2642268B2 (en) | 1991-11-22 | 1991-11-22 | Magnetic field strength measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05145143A true JPH05145143A (en) | 1993-06-11 |
| JP2642268B2 JP2642268B2 (en) | 1997-08-20 |
Family
ID=17971866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3307673A Expired - Fee Related JP2642268B2 (en) | 1991-11-22 | 1991-11-22 | Magnetic field strength measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2642268B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130009508A1 (en) * | 2010-01-06 | 2013-01-10 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Axial gap type brushless motor |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63308394A (en) * | 1987-06-10 | 1988-12-15 | Mitsubishi Electric Corp | Manufacture of magnetoresistance effect element |
| JPS6419512A (en) * | 1987-07-14 | 1989-01-23 | Sony Corp | Magneto-resistance effect type magnetic head |
| JPH01152677A (en) * | 1987-12-09 | 1989-06-15 | Nec Corp | Magnetoresistance effect device and its manufacture |
-
1991
- 1991-11-22 JP JP3307673A patent/JP2642268B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63308394A (en) * | 1987-06-10 | 1988-12-15 | Mitsubishi Electric Corp | Manufacture of magnetoresistance effect element |
| JPS6419512A (en) * | 1987-07-14 | 1989-01-23 | Sony Corp | Magneto-resistance effect type magnetic head |
| JPH01152677A (en) * | 1987-12-09 | 1989-06-15 | Nec Corp | Magnetoresistance effect device and its manufacture |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130009508A1 (en) * | 2010-01-06 | 2013-01-10 | Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) | Axial gap type brushless motor |
| US9160219B2 (en) * | 2010-01-06 | 2015-10-13 | Kobe Steel, Ltd. | Axial gap type brushless motor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2642268B2 (en) | 1997-08-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |