JPH05145143A - Magnetoresistance element and measuring method for magnetic field strength - Google Patents

Magnetoresistance element and measuring method for magnetic field strength

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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
Application number
JP3307673A
Other languages
Japanese (ja)
Other versions
JP2642268B2 (en
Inventor
Masakatsu Senda
正勝 千田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP3307673A priority Critical patent/JP2642268B2/en
Publication of JPH05145143A publication Critical patent/JPH05145143A/en
Application granted granted Critical
Publication of JP2642268B2 publication Critical patent/JP2642268B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PURPOSE:To enable an S/N ratio to be improved by providing a soft magnetic body on a conductor surface with a pair of electrodes at both edges of a magnetoresistance element. CONSTITUTION:A soft magnetic body 1 is provided at upper and lower parts of a line of a magnetoresistance element part 3 which consists of a conductor 2 with a pair of electrodes 4 at both sides directly or through a non-magnetic body. In this case, Cu is used as the conductor 2 and NiFe alloy is used as the soft magnetic body 1 and then increase in thickness of Cu and NiFe alloy reduces resistance only in the case of the conductor 2 where no soft magnetic body 1 is laminated and increases resistance due to provision of the soft magnetic body 1, thus enabling an S/N ratio to be improved.

Description

【発明の詳細な説明】Detailed Description of the Invention

【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/R=Δρ/ρ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.

【図面の簡単な説明】[Brief description of drawings]

【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.

【符号の説明】[Explanation of symbols]

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)

【特許請求の範囲】[Claims] 【請求項1】 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.
【請求項2】 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.
【請求項3】 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.
JP3307673A 1991-11-22 1991-11-22 Magnetic field strength measurement method Expired - Fee Related JP2642268B2 (en)

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)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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

Patent Citations (3)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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

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