JP2018004459A - Magnetic sensor and current sensor - Google Patents
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- 230000005291 magnetic effect Effects 0.000 title claims abstract description 341
- 230000000694 effects Effects 0.000 claims abstract description 56
- 230000005290 antiferromagnetic effect Effects 0.000 claims abstract description 44
- 230000035945 sensitivity Effects 0.000 claims abstract description 10
- 230000008878 coupling Effects 0.000 claims description 25
- 238000010168 coupling process Methods 0.000 claims description 25
- 238000005859 coupling reaction Methods 0.000 claims description 25
- 239000002885 antiferromagnetic material Substances 0.000 claims description 8
- 230000003647 oxidation Effects 0.000 claims description 8
- 238000007254 oxidation reaction Methods 0.000 claims description 8
- 239000000758 substrate Substances 0.000 claims description 8
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 claims description 5
- 230000001788 irregular Effects 0.000 claims description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 4
- 239000010410 layer Substances 0.000 description 108
- 230000005415 magnetization Effects 0.000 description 16
- 238000005259 measurement Methods 0.000 description 10
- 239000011810 insulating material Substances 0.000 description 9
- 238000001514 detection method Methods 0.000 description 7
- 230000002829 reductive effect Effects 0.000 description 5
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 4
- 239000011241 protective layer Substances 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- 230000002411 adverse Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000696 magnetic material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000010992 reflux Methods 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 230000005381 magnetic domain Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910019041 PtMn Inorganic materials 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
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Abstract
Description
本発明は、磁気センサおよび当該磁気センサを備えた電流センサに関する。 The present invention relates to a magnetic sensor and a current sensor including the magnetic sensor.
電気自動車やハイブリッドカーにおけるモータ駆動技術などの分野や、柱状トランスなどインフラ関連の分野では、比較的大きな電流が取り扱われるため、大電流を非接触で測定することが可能な電流センサが求められている。このような電流センサとしては、被測定電流からの誘導磁界を検出する磁気センサを用いたものが知られている。磁気センサ用の磁気検出素子として、例えば、ＧＭＲ（巨大磁気抵抗効果）素子などの磁気抵抗効果素子が挙げられる。 In fields such as motor drive technology in electric vehicles and hybrid cars, and in infrastructure-related fields such as columnar transformers, relatively large currents are handled, so there is a need for current sensors that can measure large currents without contact. Yes. As such a current sensor, a sensor using a magnetic sensor that detects an induced magnetic field from a current to be measured is known. Examples of the magnetic detection element for the magnetic sensor include a magnetoresistive effect element such as a GMR (giant magnetoresistive effect) element.
磁気抵抗効果素子は、検出感度が高いものの、線形性高く検出可能な磁界強度範囲が比較的狭いという特徴がある。このため、特許文献１の図３に示される電流センサのように、被測定電流と磁気抵抗効果素子との間に磁気シールドを配置して、磁気抵抗効果素子に実質的に印加される誘導磁界の強度を小さくして、被測定磁界の大きさを良好な検出特性を有する磁界強度範囲内とする方法が用いられる場合がある。 Although the magnetoresistive effect element has a high detection sensitivity, it has a feature that a detectable magnetic field intensity range is relatively narrow with high linearity. Therefore, as in the current sensor shown in FIG. 3 of Patent Document 1, a magnetic shield is disposed between the current to be measured and the magnetoresistive effect element, and an induced magnetic field that is substantially applied to the magnetoresistive effect element. In some cases, a method is used in which the intensity of the magnetic field to be measured is set within a magnetic field intensity range having good detection characteristics.
このように磁気シールドを用いることによって、磁気抵抗効果素子に実質的に印加される磁界の強度を低減させて、磁界強度の測定範囲を拡げることが実現されているが、磁気シールドに印加される磁場が数十ｍＴ程度と強い場合には、磁気シールドが軟磁性材料から構成されていても、磁気シールドに残留磁化が生じやすくなってしまう。こうして生じた磁気シールドの残留磁化に基づく磁界が磁気抵抗効果素子に印加されると、磁気抵抗効果素子のゼロ磁場ヒステリシスがマイナス側に大きくなるなどの磁気抵抗効果素子の測定精度に悪影響を与えてしまうおそれがある。 By using the magnetic shield in this way, it has been realized that the strength of the magnetic field applied to the magnetoresistive effect element is substantially reduced and the measurement range of the magnetic field strength is expanded. When the magnetic field is as strong as several tens of mT, even if the magnetic shield is made of a soft magnetic material, residual magnetization tends to occur in the magnetic shield. When a magnetic field based on the remanent magnetization of the magnetic shield generated in this way is applied to the magnetoresistive effect element, the measurement accuracy of the magnetoresistive effect element is adversely affected, such as the zero magnetic field hysteresis of the magnetoresistive effect element becoming larger on the negative side. There is a risk that.
本発明は、かかる現状を鑑み、磁気シールドおよび磁気抵抗効果素子を備える磁気センサであって、磁気センサに印加される磁場が大きい場合であっても、磁気抵抗効果素子の測定精度が低下しにくい磁気センサを提供することを目的とする。本発明は、かかる磁気センサを備える電流センサを提供することをも目的とする。 In view of the current situation, the present invention is a magnetic sensor including a magnetic shield and a magnetoresistive effect element, and even when the magnetic field applied to the magnetic sensor is large, the measurement accuracy of the magnetoresistive effect element is unlikely to decrease. An object is to provide a magnetic sensor. Another object of the present invention is to provide a current sensor including such a magnetic sensor.
上記の課題を解決するために提供される本発明は、一態様において、特定の方向に感度軸を持つ磁気抵抗効果素子と、前記磁気抵抗効果素子に印加される被測定磁界の強度を低減させる磁気シールドとを備えた磁気センサであって、前記磁気シールドは、軟磁性層と前記軟磁性層に接する反強磁性層とを備える単位積層体が複数積層された積層構造を有し、前記単位積層体が備える前記軟磁性層は、前記単位積層体が備える前記反強磁性層と交換結合していることを特徴とする磁気センサである。 In one aspect, the present invention provided to solve the above problem reduces a strength of a magnetic field to be measured applied to a magnetoresistive element having a sensitivity axis in a specific direction and the magnetoresistive element. A magnetic sensor comprising a magnetic shield, wherein the magnetic shield has a laminated structure in which a plurality of unit laminated bodies each comprising a soft magnetic layer and an antiferromagnetic layer in contact with the soft magnetic layer are laminated, The soft magnetic layer included in the multilayer body is exchange coupled with the antiferromagnetic layer included in the unit multilayer body.
磁気シールドを構成する軟磁性材料、すなわち軟磁性層は、反強磁性層と交換結合している。このため、外部磁場が印加されていない状態において軟磁性層を単磁区化することができる。それゆえ、磁気シールドに印加される磁場が大きい場合であっても、磁気抵抗効果素子に影響を与えるような残留磁化が磁気シールドに生じにくくなって、磁気センサの測定精度が低下しにくい。 The soft magnetic material constituting the magnetic shield, that is, the soft magnetic layer, is exchange coupled with the antiferromagnetic layer. For this reason, the soft magnetic layer can be made into a single magnetic domain in a state where no external magnetic field is applied. Therefore, even when the magnetic field applied to the magnetic shield is large, residual magnetization that affects the magnetoresistive element is less likely to occur in the magnetic shield, and the measurement accuracy of the magnetic sensor is unlikely to decrease.
上記の磁気センサにおいて、前記積層構造に含まれる前記単位積層体の一つが備える前記軟磁性層における交換結合に基づく磁界の向きと、前記単位積層体の一つに最近位の前記単位積層体が備える前記軟磁性層における交換結合に基づく磁界の向きとは反平行の関係を有することが好ましい。この場合には、残留磁化により磁気シールドに生じた磁界は、上記の磁界の向きが反平行の関係を有する一群の単位積層体によって還流磁界となり、磁気シールドの残留磁化に基づく磁界の影響が磁気シールドから離れた位置に及ぶ可能性が特に低減される。このため、磁気抵抗効果素子が磁気シールドの残留磁化の影響を受けることがより安定的に回避され、好ましい。 In the above magnetic sensor, the direction of the magnetic field based on exchange coupling in the soft magnetic layer provided in one of the unit laminate bodies included in the laminate structure, and the nearest unit laminate body in one of the unit laminate bodies The soft magnetic layer preferably includes an antiparallel relationship with the direction of the magnetic field based on exchange coupling. In this case, the magnetic field generated in the magnetic shield due to the remanent magnetization becomes a return magnetic field by the group of unit laminates in which the magnetic field directions are antiparallel, and the influence of the magnetic field based on the remanent magnetization of the magnetic shield is magnetic. The possibility of extending away from the shield is particularly reduced. For this reason, it is more preferable that the magnetoresistive effect element is affected by the residual magnetization of the magnetic shield, which is preferable.
上記の磁気センサにおいて、前記反強磁性層は不規則系反強磁性材料からなることが好ましい場合がある。反強磁性層が不規則系反強磁性材料からなる場合には、反強磁性層とこれに接する軟磁性層との交換結合を生じさせるために磁場中の加熱処理が必要とされない。このため、磁気シールドが備える複数の単位積層体のそれぞれに生じる交換結合を個別に制御することが容易となる。 In the above magnetic sensor, the antiferromagnetic layer may be preferably made of an irregular antiferromagnetic material. When the antiferromagnetic layer is made of an irregular antiferromagnetic material, no heat treatment in a magnetic field is required in order to cause exchange coupling between the antiferromagnetic layer and the soft magnetic layer in contact therewith. For this reason, it becomes easy to control individually the exchange coupling which arises in each of the several unit laminated body with which a magnetic shield is provided.
前記反強磁性層は、白金族元素およびＭｎを含有することが好ましい場合があり、ＩｒＭｎからなることが好ましい場合がある。ＩｒＭｎは不規則系反強磁性材料の具体例である。 The antiferromagnetic layer may preferably contain a platinum group element and Mn, and may preferably consist of IrMn. IrMn is a specific example of an irregular antiferromagnetic material.
上記の磁気センサにおける前記積層構造は、前記反強磁性層と前記軟磁性層との交互積層構造を有していてもよい。この場合には、単位積層体は反強磁性層と軟磁性層とから構成される。 The laminated structure in the magnetic sensor may have an alternate laminated structure of the antiferromagnetic layer and the soft magnetic layer. In this case, the unit laminate structure is composed of an antiferromagnetic layer and a soft magnetic layer.
上記の磁気センサにおいて、前記磁気抵抗効果素子は、異方性磁気抵抗効果素子、巨大磁気抵抗効果素子およびトンネル磁気抵抗効果素子からなる群から選ばれる１種以上の素子から構成されていてもよい。 In the above magnetic sensor, the magnetoresistive element may be composed of one or more elements selected from the group consisting of an anisotropic magnetoresistive element, a giant magnetoresistive element, and a tunnel magnetoresistive element. .
上記の磁気センサの前記磁気抵抗効果素子は、巨大磁気抵抗効果素子からなり、前記巨大磁気抵抗効果素子はセルフピン構造を有する固定層を備えていてもよい。 The magnetoresistive effect element of the magnetic sensor may be a giant magnetoresistive effect element, and the giant magnetoresistive effect element may include a fixed layer having a self-pin structure.
上記の磁気センサは、基板の上に前記磁気抵抗効果素子が形成され、その上に前記磁気シールドが形成された構造を備え、前記磁気シールドの最下層に位置する前記単位積層体は、ＮｉＦｅからなる前記軟磁性層とその上に形成された前記反強磁性層とを備えていてもよい。この場合において、前記磁気シールドは、前記磁気抵抗効果素子から最遠位に設けられた酸化保護層を備えていてもよい。 The magnetic sensor includes a structure in which the magnetoresistive effect element is formed on a substrate and the magnetic shield is formed on the substrate, and the unit laminated body located in the lowest layer of the magnetic shield is made of NiFe. The soft magnetic layer and the antiferromagnetic layer formed thereon may be provided. In this case, the magnetic shield may include an oxidation protection layer provided at a most distal position from the magnetoresistive element.
上記の磁気センサにおいて、前記軟磁性層における交換結合に基づく磁界の向きは、前記磁気抵抗効果素子の前記感度軸に沿った方向に対して直交していることが好ましい場合がある。 In the above magnetic sensor, it may be preferable that the direction of the magnetic field based on exchange coupling in the soft magnetic layer is orthogonal to the direction along the sensitivity axis of the magnetoresistive element.
上記の磁気センサは磁気平衡用コイルをさらに備えていてもよく、前記磁気平衡用コイルに流れる電流に基づき前記被測定磁界の強度を測定するものであってもよい。この場合における磁気平衡用コイルの配置は任意であるが、前記磁気平衡用コイルはスパイラルコイルであって、前記磁気抵抗効果素子と前記磁気シールドとの間に位置していることが好ましい場合がある。 The magnetic sensor may further include a magnetic balancing coil, and may measure the strength of the magnetic field to be measured based on a current flowing through the magnetic balancing coil. In this case, the arrangement of the magnetic balancing coil is arbitrary, but the magnetic balancing coil is preferably a spiral coil and preferably located between the magnetoresistive element and the magnetic shield. .
本発明は、他の一態様として、上記の磁気センサを備え、前記磁気センサは被測定電流の誘導磁界を前記被測定磁界とする電流センサを提供する。 As another aspect of the present invention, the magnetic sensor includes the above-described magnetic sensor, and the magnetic sensor provides a current sensor that uses an induced magnetic field of a current to be measured as the magnetic field to be measured.
本発明によれば、磁気シールドおよび磁気抵抗効果素子を備える磁気センサであって、印加磁場が大きい場合であっても、磁気抵抗効果素子の測定精度が低下しにくい磁気センサが提供される。また、かかる磁気センサを用いてなる電流センサも提供される。 ADVANTAGE OF THE INVENTION According to this invention, it is a magnetic sensor provided with a magnetic shield and a magnetoresistive effect element, Comprising: Even if it is a case where an applied magnetic field is large, the magnetic sensor which a measurement accuracy of a magnetoresistive effect element cannot fall easily is provided. A current sensor using such a magnetic sensor is also provided.
図１は、本発明の一実施形態に係る磁気センサの構造を概念的に示す断面図である。 FIG. 1 is a cross-sectional view conceptually showing the structure of a magnetic sensor according to an embodiment of the present invention.
本発明の一実施形態に係る磁気センサ１は、図１に示されるように、磁気抵抗効果素子１１および磁気シールド１５を備える。 As shown in FIG. 1, the magnetic sensor 1 according to an embodiment of the present invention includes a magnetoresistive effect element 11 and a magnetic shield 15.
本発明の一実施形態に係る磁気センサ１の磁気抵抗効果素子１１は、ミアンダ形状（複数の長尺パターンが折り返すようにつながって構成される形状）を有する巨大磁気抵抗効果素子（ＧＭＲ素子）を備える。図１は、ミアンダ形状を構成する複数の長尺パターンの長軸方向に沿った方向を法線とする面で磁気センサ１を切断して得られる断面図である。この断面内方向の１つであるＸ１−Ｘ２方向が磁気抵抗効果素子１１の感度軸方向である。磁気抵抗効果素子１１は、基板２９上に設けられた絶縁材料（アルミナ）からなる層ＩＭ１上に形成され、図１では３層構造を有する電極ＥＬ１に電気的に接続される。電極ＥＬ１は接点用の電極ＥＬ２に電気的に接続される。磁気抵抗効果素子１１および電極ＥＬ１は、絶縁材料（アルミナ）からなる層ＩＭ１によって覆われている。この絶縁材料（アルミナ）からなる層ＩＭ１を覆うように、他の絶縁材料（窒化ケイ素）からなる層ＩＭ２が設けられる。 The magnetoresistive effect element 11 of the magnetic sensor 1 according to an embodiment of the present invention is a giant magnetoresistive effect element (GMR element) having a meander shape (a shape formed by connecting a plurality of long patterns so as to be folded back). Prepare. FIG. 1 is a cross-sectional view obtained by cutting the magnetic sensor 1 along a plane whose normal is a direction along the long axis direction of a plurality of long patterns constituting a meander shape. The X1-X2 direction, which is one of the in-section directions, is the sensitivity axis direction of the magnetoresistive effect element 11. The magnetoresistive effect element 11 is formed on a layer IM1 made of an insulating material (alumina) provided on a substrate 29, and is electrically connected to an electrode EL1 having a three-layer structure in FIG. The electrode EL1 is electrically connected to the contact electrode EL2. The magnetoresistive element 11 and the electrode EL1 are covered with a layer IM1 made of an insulating material (alumina). A layer IM2 made of another insulating material (silicon nitride) is provided so as to cover the layer IM1 made of this insulating material (alumina).
磁気シールド１５は、他の絶縁材料（窒化ケイ素）からなる層ＩＭ２の上に設けられる。磁気シールド１５と磁気抵抗効果素子１１との離間距離は、絶縁材料（アルミナ）からなる層ＩＭ１の厚さおよび他の絶縁材料（窒化ケイ素）からなる層ＩＭ２の厚さによって調整される。 The magnetic shield 15 is provided on the layer IM2 made of another insulating material (silicon nitride). The separation distance between the magnetic shield 15 and the magnetoresistive effect element 11 is adjusted by the thickness of the layer IM1 made of an insulating material (alumina) and the thickness of the layer IM2 made of another insulating material (silicon nitride).
本発明の一実施形態に係る磁気センサ１では、磁気シールド１５は、軟磁性層ＳＭとこの軟磁性層ＳＭに接する反強磁性層ＡＦとからなる単位積層体１５−ｉ（１５−１〜１５−６）が６層積層されてなる積層構造を有し、これらの軟磁性層ＳＭと反強磁性層ＡＦとは交換結合している。図１に示される磁気センサ１では、磁気シールド１５は６層の単位積層体１５−１〜１５−６を備えるが、これに限定されない。単位積層体１５−ｉの積層数は、磁気シールド１５に求められる特性に応じて適宜設定される。 In the magnetic sensor 1 according to one embodiment of the present invention, the magnetic shield 15 is composed of unit laminated bodies 15-i (15-1 to 15-15) including the soft magnetic layer SM and the antiferromagnetic layer AF in contact with the soft magnetic layer SM. −6) has a laminated structure in which six layers are laminated, and the soft magnetic layer SM and the antiferromagnetic layer AF are exchange-coupled. In the magnetic sensor 1 shown in FIG. 1, the magnetic shield 15 includes the six-layer unit laminated bodies 15-1 to 15-6, but is not limited thereto. The number of unit laminates 15-i is appropriately set according to the characteristics required for the magnetic shield 15.
軟磁性層ＳＭはＦｅ，Ｃｏ，Ｎｉなど鉄族元素を含む軟磁性材料から構成される。軟磁性層ＳＭの厚さは限定されない。３〜３０ｎｍとすることが例示される。 The soft magnetic layer SM is made of a soft magnetic material containing an iron group element such as Fe, Co, or Ni. The thickness of the soft magnetic layer SM is not limited. It is exemplified that the thickness is 3 to 30 nm.
反強磁性層ＡＦは、Ｉｒ，Ｐｔなどの白金族元素およびＭｎを含む反強磁性材料から構成される。反強磁性層ＡＦの厚さは構成材料によって適宜設定される。反強磁性層ＡＦがＩｒＭｎからなる場合には４〜１０ｎｍとすることが例示され、反強磁性層ＡＦがＰｔＭｎからなる場合には１０〜３０ｎｍとすることが例示される。反強磁性層ＡＦを構成する材料が不規則系反強磁性材料からなる場合（具体例としてＩｒＭｎからなる場合が挙げられる。）には、磁場中成膜によって反強磁性層ＡＦの交換結合の向きを設定できるため、複数の単位積層体１５−１〜１５−６のそれぞれの反強磁性層ＡＦの交換結合の向きを個別に設定することができる。その結果として、複数の単位積層体１５−１〜１５−６のそれぞれの軟磁性層ＳＭにおける反強磁性層ＡＦとの交換結合により生じる磁化の向きも、個別に設定することが可能である。 The antiferromagnetic layer AF is made of an antiferromagnetic material containing a platinum group element such as Ir or Pt and Mn. The thickness of the antiferromagnetic layer AF is appropriately set depending on the constituent material. When the antiferromagnetic layer AF is made of IrMn, the thickness is 4 to 10 nm. When the antiferromagnetic layer AF is made of PtMn, the thickness is 10 to 30 nm. When the material composing the antiferromagnetic layer AF is made of a disordered antiferromagnetic material (specifically, it is made of IrMn), the exchange coupling of the antiferromagnetic layer AF can be performed by film formation in a magnetic field. Since the direction can be set, the direction of exchange coupling of each of the antiferromagnetic layers AF of the plurality of unit laminate bodies 15-1 to 15-6 can be individually set. As a result, the direction of magnetization caused by exchange coupling with the antiferromagnetic layer AF in each soft magnetic layer SM of the plurality of unit laminate bodies 15-1 to 15-6 can be set individually.
軟磁性層ＳＭおよび反強磁性層ＡＦはいずれもスパッタリングなどの公知の技術により成膜することができる。最下層（基板２９に最近位）に位置する単位積層体１５−１の軟磁性層ＳＭの結晶構造は、ｆｃｃ構造で（１１１）配向させるために、ＮｉＦｅから構成されることが好ましい。 Both the soft magnetic layer SM and the antiferromagnetic layer AF can be formed by a known technique such as sputtering. The crystal structure of the soft magnetic layer SM of the unit laminate 15-1 located in the lowermost layer (most recent position on the substrate 29) is preferably composed of NiFe in order to have the (111) orientation in the fcc structure.
複数の単位積層体１５−１〜１５−６のそれぞれを構成する軟磁性層ＳＭと反強磁性層ＡＦとの積層方向はＹ１−Ｙ２方向であり、軟磁性層ＳＭがＹ１−Ｙ２方向Ｙ１側（磁気抵抗効果素子１１に近位側）に位置し、反強磁性層ＡＦがＹ１−Ｙ２方向Ｙ２側（磁気抵抗効果素子１１に遠位側）に位置する。複数の単位積層体１５−１〜１５−６のそれぞれの積層方向もＹ１−Ｙ２方向である。磁気シールド１５は、磁気抵抗効果素子１１に最遠位な位置（Ｙ１−Ｙ２方向Ｙ２側端部）にＴａなどから構成される酸化保護層ＰＬを有する。酸化保護層ＰＬもスパッタリングなどの公知の技術により成膜することができる。 The stacking direction of the soft magnetic layer SM and the antiferromagnetic layer AF constituting each of the plurality of unit stacked bodies 15-1 to 15-6 is the Y1-Y2 direction, and the soft magnetic layer SM is on the Y1-Y2 direction Y1 side. The antiferromagnetic layer AF is located on the Y1-Y2 direction Y2 side (distal side with respect to the magnetoresistive effect element 11). The stacking direction of each of the plurality of unit stacked bodies 15-1 to 15-6 is also the Y1-Y2 direction. The magnetic shield 15 has an oxidation protection layer PL made of Ta or the like at a position farthest from the magnetoresistive element 11 (Y1-Y2 direction Y2 side end). The oxidation protective layer PL can also be formed by a known technique such as sputtering.
磁気シールド１５において、上記のように軟磁性層ＳＭと反強磁性層ＡＦとが交換結合していることにより、磁気センサ１に対して外部磁場が印加されていない状態において軟磁性層ＳＭを単磁区化することができる。このため、磁気シールド１５に印加される磁場が大きい場合であっても、磁気抵抗効果素子１１に影響を与えるような残留磁化が磁気シールド１５に生じにくくなって、磁気センサ１の測定精度が低下しにくい。 In the magnetic shield 15, the soft magnetic layer SM and the antiferromagnetic layer AF are exchange-coupled as described above, so that the soft magnetic layer SM is formed in a state where no external magnetic field is applied to the magnetic sensor 1. Can be made into a magnetic domain. For this reason, even when the magnetic field applied to the magnetic shield 15 is large, residual magnetization that affects the magnetoresistive effect element 11 is less likely to occur in the magnetic shield 15, and the measurement accuracy of the magnetic sensor 1 is reduced. Hard to do.
図２は、図１における磁気シールド１５の部分を拡大した図である。磁気シールド１５の単位積層体１５−１〜１５−６の軟磁性層ＳＭにおいて反強磁性層ＡＦとの交換結合により生じる磁化の向きは限定されない。図２に示されるように、Ｘ１−Ｘ２方向およびＹ１−Ｙ２方向に垂直な方向（紙面に垂直な方向であり、「Ｚ１−Ｚ２方向」という。）、すなわち、感度軸方向に対して直交していてもよい。この場合には、外部磁場が印加されていない状態において磁気シールド１５の単位積層体１５−１〜１５−６からの漏れ磁界が磁気抵抗効果素子１１に影響を及ぼすことがあっても、磁気センサ１のゼロ磁場ヒステリシスを大きくする要因にはなりにくい。 FIG. 2 is an enlarged view of a portion of the magnetic shield 15 in FIG. The direction of magnetization generated by exchange coupling with the antiferromagnetic layer AF in the soft magnetic layer SM of the unit laminate bodies 15-1 to 15-6 of the magnetic shield 15 is not limited. As shown in FIG. 2, the direction perpendicular to the X1-X2 direction and the Y1-Y2 direction (the direction perpendicular to the paper surface, referred to as “Z1-Z2 direction”), that is, perpendicular to the sensitivity axis direction. It may be. In this case, even if a leakage magnetic field from the unit laminates 15-1 to 15-6 of the magnetic shield 15 may affect the magnetoresistive effect element 11 in a state where no external magnetic field is applied, the magnetic sensor It is difficult to increase the zero magnetic field hysteresis of 1.
図２に示されるように、磁気シールド１５の単位積層体１５−１の軟磁性層ＳＭは、軟磁性層ＳＭに接するように積層されてなる反強磁性層ＡＦとの交換結合により、紙面に垂直方向手前側（この向きを「Ｚ１−Ｚ２方向Ｚ１側」という。）に磁化されている。そして、単位積層体１５−１に最近位に位置する単位積層体１５−２における軟磁性層ＳＭの交換結合に基づく磁界の向きは、紙面に垂直方向奥側（この向きを「Ｚ１−Ｚ２方向Ｚ２側」という。）であり、単位積層体１５−１の軟磁性層ＳＭの交換結合に基づく磁界の向きと反平行の関係にある。 As shown in FIG. 2, the soft magnetic layer SM of the unit laminated body 15-1 of the magnetic shield 15 is placed on the paper surface by exchange coupling with the antiferromagnetic layer AF laminated so as to be in contact with the soft magnetic layer SM. Magnetized on the front side in the vertical direction (this direction is referred to as “Z1-Z2 direction Z1 side”). The direction of the magnetic field based on the exchange coupling of the soft magnetic layer SM in the unit laminated body 15-2 located closest to the unit laminated body 15-1 is perpendicular to the paper surface (this direction is referred to as “Z1-Z2 direction”). Z2 side ”)), which is antiparallel to the direction of the magnetic field based on the exchange coupling of the soft magnetic layer SM of the unit laminate body 15-1.
このように最近位に位置する２つの単位積層体における軟磁性層ＳＭの交換結合に基づく磁界の向きが反平行の関係を有していることにより、これらの２つの単位積層体（具体的には単位積層体１５−１および単位積層体１５−２）の軟磁性層ＳＭが磁気的に結合して、還流磁界が形成される。このため、磁気シールド１５の軟磁性層ＳＭの交換結合に基づく磁界の影響は磁気シールド１５の近傍に制限される。それゆえ、外部磁場が印加されていない状態において、磁気シールド１５の周囲に位置する要素、特に、磁気抵抗効果素子１１は、磁気シールド１５からの磁気的影響を受けにくい。最近位に位置する一組の軟磁性層ＳＭの交換結合に基づく磁界の向きを反平行とすることを容易にする観点から、磁気シールド１５が備える反強磁性層ＡＦをＩｒＭｎのような不規則系反強磁性材料から構成することが好ましい。前述のように、不規則系反強磁性材料からなる反強磁性層ＡＦの交換結合の向きは磁場中成膜時の磁場の向きによって設定可能であるから、単位積層体１５−２の反強磁性層ＡＦを磁場中成膜することにより、下層の単位積層体１５−１の軟磁性層ＳＭへの影響を抑えて、単位積層体１５−１の軟磁性層ＳＭの磁化の方向と反平行の関係を有するように、単位積層体１５−２の軟磁性層ＳＭを磁化することが可能である。 As described above, the two unit laminates (specifically, the direction of the magnetic field based on the exchange coupling of the soft magnetic layer SM in the two nearest unit laminates has an antiparallel relationship. The unit laminate 15-1 and the soft magnetic layer SM of the unit laminate 15-2) are magnetically coupled to form a reflux magnetic field. For this reason, the influence of the magnetic field based on the exchange coupling of the soft magnetic layer SM of the magnetic shield 15 is limited to the vicinity of the magnetic shield 15. Therefore, in a state where no external magnetic field is applied, the elements positioned around the magnetic shield 15, particularly the magnetoresistive effect element 11, are not easily affected by the magnetic shield 15. From the viewpoint of facilitating making the direction of the magnetic field based on the exchange coupling of the pair of soft magnetic layers SM located in the nearest position antiparallel, the antiferromagnetic layer AF provided in the magnetic shield 15 is irregularly formed like IrMn. It is preferable to comprise a system antiferromagnetic material. As described above, the direction of exchange coupling of the antiferromagnetic layer AF made of a disordered antiferromagnetic material can be set by the direction of the magnetic field at the time of film formation in the magnetic field. By forming the magnetic layer AF in a magnetic field, the influence of the lower unit laminate 15-1 on the soft magnetic layer SM is suppressed, and the direction of magnetization of the soft magnetic layer SM of the unit laminate 15-1 is antiparallel. It is possible to magnetize the soft magnetic layer SM of the unit laminate body 15-2 so as to have the following relationship.
図２に示される磁気シールド１５では、単位積層体１５−２の上に積層される単位積層体１５−３〜１５−６のそれぞれについても、軟磁性層ＳＭの交換結合に基づく磁界の向きが、最近位の単位積層体における軟磁性層ＳＭの交換結合に基づく磁界の向きと反平行の関係となるように、軟磁性層ＳＭの交換結合に基づく磁化が行われている。こうして、磁気シールド１５は、軟磁性層ＳＭが反強磁性層ＡＦとの交換結合に基づいて磁化していても、磁気シールド１５の外部に流れ出る漏れ磁界は限定的となる。それゆえ、磁気シールド１５の周りに位置する要素がこの漏れ磁界により磁気的影響を受けることが抑制されている。 In the magnetic shield 15 shown in FIG. 2, each of the unit laminate bodies 15-3 to 15-6 laminated on the unit laminate body 15-2 also has a magnetic field direction based on the exchange coupling of the soft magnetic layer SM. The magnetization based on the exchange coupling of the soft magnetic layer SM is performed so as to have an antiparallel relationship with the direction of the magnetic field based on the exchange coupling of the soft magnetic layer SM in the nearest unit laminated body. Thus, in the magnetic shield 15, even if the soft magnetic layer SM is magnetized based on exchange coupling with the antiferromagnetic layer AF, the leakage magnetic field flowing out of the magnetic shield 15 is limited. Therefore, the elements located around the magnetic shield 15 are suppressed from being magnetically affected by this leakage magnetic field.
なお、図２に示される磁気シールド１５は、６つの単位積層体１５−１〜１５−６が積層した積層構造を有し、単位積層体１５−１〜１５−６のそれぞれは軟磁性層ＳＭと反強磁性層ＡＦとからなるため、図２に示される磁気シールド１５は軟磁性層ＳＭと反強磁性層ＡＦとが交互に積層する構造を有しているともいえる。 The magnetic shield 15 shown in FIG. 2 has a laminated structure in which six unit laminated bodies 15-1 to 15-6 are laminated, and each of the unit laminated bodies 15-1 to 15-6 is a soft magnetic layer SM. 2 and the antiferromagnetic layer AF, it can be said that the magnetic shield 15 shown in FIG. 2 has a structure in which the soft magnetic layers SM and the antiferromagnetic layers AF are alternately stacked.
図３は、本発明の他の一実施形態に係る磁気センサの構造を概念的に示す断面図である。図３に示される磁気センサ１Ａは、図１に示される磁気センサ１と同様に磁気抵抗効果素子１１および磁気シールド１５を備え、さらに磁気抵抗効果素子１１と磁気シールド１５との間にスパイラル形状を有する磁気平衡用コイル１６を備える。磁気平衡用コイルは、磁気抵抗効果素子１１と磁気シールド１５との間に位置することにより、磁気シールド１５により減衰した状態で印加される外部磁場をキャンセルするような誘導磁界を比較的小電流により生じさせることが可能となる。このため、磁気平衡型の磁気センサを省電力で動作させることが可能である。 FIG. 3 is a cross-sectional view conceptually showing the structure of a magnetic sensor according to another embodiment of the present invention. A magnetic sensor 1A shown in FIG. 3 includes a magnetoresistive effect element 11 and a magnetic shield 15 similarly to the magnetic sensor 1 shown in FIG. 1, and a spiral shape is formed between the magnetoresistive effect element 11 and the magnetic shield 15. The magnetic balance coil 16 is provided. The magnetic balancing coil is positioned between the magnetoresistive effect element 11 and the magnetic shield 15 so that an induced magnetic field that cancels the external magnetic field applied in a state attenuated by the magnetic shield 15 is generated by a relatively small current. Can be generated. For this reason, it is possible to operate the magnetic balance type magnetic sensor with power saving.
以上の実施形態では、磁気センサ１が備える磁気抵抗効果素子１１がＧＭＲ素子からなる場合を具体例としているが、これに限定されない。限定されない一例において、磁気抵抗効果素子は、異方性磁気抵抗効果素子（ＡＭＲ素子）、巨大磁気抵抗効果素子（ＧＭＲ素子）およびトンネル磁気抵抗効果素子（ＴＭＲ素子）からなる群から選ばれる１種以上の素子からなる。 In the above embodiment, the case where the magnetoresistive effect element 11 included in the magnetic sensor 1 is a GMR element is taken as a specific example, but the present invention is not limited to this. In one non-limiting example, the magnetoresistive element is one selected from the group consisting of an anisotropic magnetoresistive element (AMR element), a giant magnetoresistive element (GMR element), and a tunnel magnetoresistive element (TMR element). It consists of the above elements.
なお、磁気センサ１が備える磁気抵抗効果素子１１を構成するＧＭＲ素子の固定層がセルフピン構造を有する場合には、固定層の磁化は磁場中成膜によって行うことができ、成膜後に磁場中の加熱処理が必要とされない。このため、同一基板上に固定層の磁化の向きが異なるＧＭＲ素子を配置でき、一基板上にフルブリッジ回路を構成することが可能となる。 When the fixed layer of the GMR element constituting the magnetoresistive effect element 11 included in the magnetic sensor 1 has a self-pinned structure, the magnetization of the fixed layer can be performed by film formation in a magnetic field. No heat treatment is required. For this reason, GMR elements having different magnetization directions of the fixed layers can be arranged on the same substrate, and a full bridge circuit can be formed on one substrate.
本発明の一実施形態に係る磁気抵抗効果素子を備えた磁気センサは、電流センサとして好適に使用されうる。 A magnetic sensor including a magnetoresistive effect element according to an embodiment of the present invention can be suitably used as a current sensor.
本発明の一実施形態に係る電流センサの具体例として、磁気比例式電流センサおよび磁気平衡式電流センサが挙げられる。 Specific examples of the current sensor according to the embodiment of the present invention include a magnetic proportional current sensor and a magnetic balanced current sensor.
磁気比例式電流センサの具体例は、図１に示される磁気センサ１を用いる場合であり、かかる電流センサでは、図１の上方（磁気抵抗効果素子１１からみて磁気シールド１５の酸化保護層ＰＬよりもさらに遠位）において、被測定電流が流れる電流線がＺ１−Ｚ２方向に延びるように位置する。被測定磁界となる被測定電流の誘導磁界は、磁気抵抗効果素子１１に対して感度軸方向（Ｘ１−Ｘ２方向）に沿った方向に印加される。被測定磁界の一部はより透磁率の高い磁気シールド１５を通るため、磁気抵抗効果素子１１に実質的に印加される被測定磁界の強度を低減させることができる。それゆえ、磁気センサ１の測定範囲を拡げることが可能となる。しかも、磁気シールド１５の軟磁性層ＳＭがこれに接するように位置する反強磁性層ＡＦとの交換結合により磁化するため、被測定電流の誘導磁界からなる被測定磁界の印加が終了したときに、磁気抵抗効果素子１１に悪影響を及ぼす残留磁化が磁気シールド１５に生じにくい。 A specific example of the magnetic proportional current sensor is a case where the magnetic sensor 1 shown in FIG. 1 is used. In such a current sensor, the upper part of FIG. 1 (from the oxidation protection layer PL of the magnetic shield 15 as viewed from the magnetoresistive effect element 11). Further, the current line through which the current to be measured flows is positioned so as to extend in the Z1-Z2 direction. An induced magnetic field of a current to be measured that becomes a magnetic field to be measured is applied to the magnetoresistive element 11 in a direction along the sensitivity axis direction (X1-X2 direction). Since a part of the magnetic field to be measured passes through the magnetic shield 15 having a higher magnetic permeability, the strength of the magnetic field to be measured that is substantially applied to the magnetoresistive effect element 11 can be reduced. Therefore, the measurement range of the magnetic sensor 1 can be expanded. Moreover, since the soft magnetic layer SM of the magnetic shield 15 is magnetized by exchange coupling with the antiferromagnetic layer AF positioned so as to be in contact therewith, the application of the magnetic field to be measured, which is an induced magnetic field of the current to be measured, is completed. The residual magnetization that adversely affects the magnetoresistive element 11 is unlikely to occur in the magnetic shield 15.
好ましい一例において、磁気比例式電流センサは、４つの磁気抵抗効果素子１１を備え、被測定電流の誘導磁界からなる被測定磁界に応じた電位差を生じる２つの出力を備える磁界検出ブリッジ回路を有する。このブリッジ回路を有する磁気比例式電流センサでは、被測定磁界に応じて磁界検出ブリッジ回路から出力される電位差により、被測定電流が測定される。 In a preferred example, the magnetic proportional current sensor includes four magnetoresistive effect elements 11 and includes a magnetic field detection bridge circuit including two outputs that generate a potential difference corresponding to a magnetic field to be measured including an induced magnetic field of the current to be measured. In the magnetic proportional current sensor having this bridge circuit, the measured current is measured by the potential difference output from the magnetic field detection bridge circuit according to the measured magnetic field.
磁気平衡式電流センサの具体例は、図３に示される磁気センサ１Ａを用いる場合であり、かかる電流センサでは、図３の上方（磁気抵抗効果素子１１からみて磁気シールド１５の保護層ＰＬよりもさらに遠位）において、被測定電流が流れる電流線がＺ１−Ｚ２方向に延びるように位置する。被測定磁界である被測定電流の誘導磁界は、磁気抵抗効果素子１１に対して感度軸方向（Ｘ１−Ｘ２方向）に沿った方向に印加される。被測定磁界の一部はより透磁率の高い磁気シールド１５を通るため、磁気抵抗効果素子１１に実質的に印加される被測定磁界の強度を低減させることができる。それゆえ、磁気抵抗効果素子１１に実質的に印加される被測定電流による磁界をキャンセルするような誘導磁界を発生させるべく磁気平衡用コイル１６に流される電流量を少なくすることができ、電流センサの省電力化が実現される。しかも、磁気シールド１５の軟磁性層ＳＭがこれに接するように位置する反強磁性層ＡＦとの交換結合により磁化するため、被測定電流の誘導磁界からなる被測定磁界の磁気センサ１への印加が終了したときに、磁気抵抗効果素子１１に悪影響を及ぼす残留磁化が磁気シールド１５に生じにくい。 A specific example of the magnetic balance type current sensor is a case where the magnetic sensor 1A shown in FIG. 3 is used. In such a current sensor, the upper part of FIG. 3 (from the magnetoresistive effect element 11 as compared with the protective layer PL of the magnetic shield 15). Further, the current line through which the current to be measured flows is positioned so as to extend in the Z1-Z2 direction. An induced magnetic field of a current to be measured, which is a magnetic field to be measured, is applied to the magnetoresistive element 11 in a direction along the sensitivity axis direction (X1-X2 direction). Since a part of the magnetic field to be measured passes through the magnetic shield 15 having a higher magnetic permeability, the strength of the magnetic field to be measured that is substantially applied to the magnetoresistive effect element 11 can be reduced. Therefore, it is possible to reduce the amount of current passed through the magnetic balancing coil 16 so as to generate an induced magnetic field that cancels the magnetic field due to the current to be measured applied to the magnetoresistive effect element 11. Power saving is realized. In addition, since the soft magnetic layer SM of the magnetic shield 15 is magnetized by exchange coupling with the antiferromagnetic layer AF positioned so as to be in contact therewith, the magnetic field to be measured, which is an induced magnetic field of the current to be measured, is applied to the magnetic sensor 1. When this is finished, residual magnetization that adversely affects the magnetoresistive element 11 is unlikely to occur in the magnetic shield 15.
好ましい一例において、磁気平衡式電流センサは、４つの磁気抵抗効果素子１１を備え、被測定電流からの誘導磁界からなる被測定磁界およびこの被測定磁界をキャンセルするように印加された磁気平衡用コイル１６からの誘導磁界に応じた電位差を生じる２つの出力を備える磁界検出ブリッジ回路を有する。このブリッジ回路を有する磁気平衡式電流センサでは、磁界検出ブリッジ回路から出力される電位差がゼロとなったときに磁気平衡用コイル１６に流れる電流に基づいて、被測定電流が測定される。 In a preferred example, the magnetic balance type current sensor includes four magnetoresistive effect elements 11, and a magnetic field to be measured including an induced magnetic field from the current to be measured and a magnetic balance coil applied to cancel the magnetic field to be measured. 16 includes a magnetic field detection bridge circuit having two outputs that generate a potential difference according to the induced magnetic field from 16. In the magnetic balance type current sensor having this bridge circuit, the current to be measured is measured based on the current flowing through the magnetic balance coil 16 when the potential difference output from the magnetic field detection bridge circuit becomes zero.
以上説明した実施形態は、本発明の理解を容易にするために記載されたものであって、本発明を限定するために記載されたものではない。したがって、上記実施形態に開示された各要素は、本発明の技術的範囲に属する全ての設計変更や均等物をも含む趣旨である。 The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.
以下、実施例等により本発明をさらに具体的に説明するが、本発明の範囲はこれらの実施例等に限定されるものではない。 EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.
（実施例１）
図１に示される断面構造と同様の構造を有する磁気センサを作製した。磁気抵抗効果素子はＧＭＲ素子であった。磁気シールドの形状は、平面形状が６５０μｍ×１００μｍであり、ＮｉＦｅからなり厚さ１０ｎｍの軟磁性層とその上に積層されたＩｒＭｎからなり厚さ６ｎｍの反強磁性層とからなる単位積層体を３０層積層し、さらにＴａからなり厚さ１０ｎｍの酸化保護層を積層することにより形成した。軟磁性層、反強磁性層、および酸化保護層はスパッタリングにより形成した。
Example 1
A magnetic sensor having a structure similar to the cross-sectional structure shown in FIG. 1 was produced. The magnetoresistive effect element was a GMR element. The planar shape of the magnetic shield is 650 μm × 100 μm, and a unit laminate comprising a soft magnetic layer made of NiFe and a thickness of 10 nm and an IrMn layer made of IrMn laminated thereon is formed. 30 layers were stacked, and further an oxidation protective layer made of Ta and having a thickness of 10 nm was stacked. The soft magnetic layer, antiferromagnetic layer, and oxidation protection layer were formed by sputtering.
（比較例１）
実施例１と同様の構造であるが、積層構造を有する磁気シールドに代えて、厚さ３００ｎｍのＮｉＦｅからなるめっき層を磁気シールドとする磁気センサを作製した。
(Comparative Example 1)
A magnetic sensor having the same structure as that of Example 1 but using a plating layer made of NiFe having a thickness of 300 nm as a magnetic shield instead of the magnetic shield having a laminated structure was manufactured.
（測定例１）ゼロ磁場ヒステリシスの測定
実施例１により作製した磁気センサおよび比較例１により作製した磁気センサのそれぞれについて、印加した外部磁場の最大強度（最大印加磁場）を変化させながらヒステリシスループを測定した。このヒステリシスループから、ゼロ磁場ヒステリシスＺＨ（単位：％／ＦＳ）を測定した。ゼロ磁場ヒステリシスＺＨは、フルブリッジ出力曲線における出力の最大値（正の最大磁場を印加したときの値−負の最大磁場を印加したときの値）に対するゼロ磁場における出力の大きさ（正の最大磁場の印加から印加磁場ゼロまで変化させたときの値−負の最大磁場の印加から印加磁場ゼロまで変化させたときの値）の割合である。測定結果を図４に示す。
(Measurement Example 1) Measurement of Zero Magnetic Field Hysteresis For each of the magnetic sensor produced in Example 1 and the magnetic sensor produced in Comparative Example 1, a hysteresis loop was applied while changing the maximum intensity (maximum applied magnetic field) of the applied external magnetic field. It was measured. From this hysteresis loop, zero magnetic field hysteresis ZH (unit:% / FS) was measured. The zero magnetic field hysteresis ZH is the magnitude of the output in the zero magnetic field (the maximum positive value) with respect to the maximum value in the full-bridge output curve (the value when the positive maximum magnetic field is applied-the value when the negative maximum magnetic field is applied). (Value when changing from application of magnetic field to zero applied magnetic field−value when changing from application of negative maximum magnetic field to zero applied magnetic field). The measurement results are shown in FIG.
図４に示されるように、実施例１に係る磁気センサでは最大印加磁場が大きくなっても、ゼロ磁場ヒステリシスに変化は認められなかった。これに対し、比較例１に係る磁気センサでは最大印加磁場が１００ｍＴを超えて大きくなると、ゼロ磁場ヒステリシスがマイナス側に大きな値となった。これは、印加した外部磁場によって磁気シールドにおいて外部磁場の向きと等しい向きに残留磁化が生じ、この残留磁場に基づく還流磁場が磁気センサに印加された（還流磁場であるから、印加の向きは外部磁場の印加の向きと反対向きである。）ためであると考えられる。 As shown in FIG. 4, in the magnetic sensor according to Example 1, no change was observed in the zero magnetic field hysteresis even when the maximum applied magnetic field was increased. On the other hand, in the magnetic sensor according to Comparative Example 1, when the maximum applied magnetic field increased beyond 100 mT, the zero magnetic field hysteresis became a large value on the negative side. This is because the applied external magnetic field generates residual magnetization in the magnetic shield in the same direction as the external magnetic field, and a reflux magnetic field based on this residual magnetic field is applied to the magnetic sensor (because it is a reflux magnetic field, the direction of application is external). This is considered to be because the direction is opposite to the direction of application of the magnetic field.
本発明の一実施形態に係る磁気抵抗効果素子を備えた磁気センサは、柱状トランスなどのインフラ設備の電流センサの構成要素や、電気自動車、ハイブリッドカーなどの電流センサの構成要素として好適に使用されうる。 A magnetic sensor including a magnetoresistive effect element according to an embodiment of the present invention is suitably used as a component of a current sensor for infrastructure equipment such as a columnar transformer or a component of a current sensor for an electric vehicle, a hybrid car, or the like. sell.
１，１Ａ 磁気センサ
１１ 磁気抵抗効果素子
ＩＭ１ 絶縁材料からなる層
ＩＭ２ 他の絶縁材料からなる層
ＥＬ１ 電極
ＥＬ２ 接点用の電極
１５ 磁気シールド
１５−１〜１５−６ 単位積層体
１６ 磁気平衡用コイル
ＳＭ 軟磁性層
ＡＦ 反強磁性層
ＰＬ 酸化保護層
２９ 基板
1, 1A Magnetic sensor 11 Magnetoresistive element IM1 Layer made of insulating material IM2 Layer made of other insulating material EL1 Electrode EL2 Contact electrode 15 Magnetic shield 15-1 to 15-6 Unit laminated body 16 Magnetic balancing coil SM Soft magnetic layer AF Antiferromagnetic layer PL Oxidation protective layer 29 Substrate
Claims (14)
前記磁気シールドは、軟磁性層と前記軟磁性層に接する反強磁性層とを備える単位積層体が複数積層された積層構造を有し、
前記単位積層体が備える前記軟磁性層は、前記単位積層体が備える前記反強磁性層と交換結合していること
を特徴とする磁気センサ。 A magnetic sensor comprising a magnetoresistive effect element having a sensitivity axis in a specific direction, and a magnetic shield for reducing the strength of a magnetic field to be measured applied to the magnetoresistive effect element,
The magnetic shield has a laminated structure in which a plurality of unit laminated bodies each including a soft magnetic layer and an antiferromagnetic layer in contact with the soft magnetic layer are laminated,
The magnetic sensor provided in the unit laminated body is exchange-coupled with the antiferromagnetic layer provided in the unit laminated body.
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