JP3756732B2

JP3756732B2 - Magnetoresistive element

Info

Publication number: JP3756732B2
Application number: JP2000206849A
Authority: JP
Inventors: 健一田中
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 2000-07-04
Filing date: 2000-07-04
Publication date: 2006-03-15
Anticipated expiration: 2020-07-04
Also published as: JP2002026424A

Description

【０００１】
【発明の属する技術分野】
本発明は、磁気ヘッド等に用いられる磁気抵抗効果型素子に関し、特にスピンバルブ効果を利用した磁気抵抗効果型素子に関する。
【０００２】
【従来の技術】
図３は、この種の従来の磁気抵抗効果型素子の従来技術を説明するためのものであり、この磁気抵抗効果型素子２１は、タンタル等の非磁性材料からなる下地層２２上に、順に、ＰｔＭｎ合金等からなる反強磁性層２３、Ｃｏ等からなる第１の強磁性層２４、Ｃｕ等からなる非磁性導電層２５、ＦｅＮｉ合金等からなる第２の強磁性層２６が積層されて、第２の強磁性層２６上には、非磁性導電層２５、第１の強磁性層２４、反強磁性層２３、タンタル等の非磁性材料からなる保護層２７が順次積層されており、これら９層の両側にはＣｏＰｔ合金等からなる一対のバイアス層２８が配設され、バイアス層２８上にそれぞれＡｕ等からなる電極層２９が形成されている。
【０００３】
そして、第１の強磁性層２４は、反強磁性層２３との界面にて発生する交換結合による交換異方性磁界により磁化されて、反強磁性層２３と第１の強磁性層２４とが磁気的に結合されており、この結合によって第１の強磁性層２４の磁化方向は、図示Ｙ方向（図３の紙面に向かう）に固定されている。
【０００４】
また、図示Ｘ方向に磁化されているバイアス層２８の影響を受けて、第２の強磁性層２６は全体として単磁区化されており、その磁化が図示Ｘ方向に揃えられた状態となっている。
【０００５】
このように構成された磁気抵抗効果素子２１は、例えば磁気ヘッドに適用されて磁気ディスク装置に組み込まれ、電極層２９からバイアス層２８を介して第１の強磁性層２４、非磁性導電層２５、及び第２の強磁性層２６に検出電流が与えられ、図示Ｚ方向に回転走行する磁気ディスクからの漏れ磁界が印加磁界として図示Ｙ方向に沿って与えられると、第２の強磁性層２６の磁化が図示Ｘ方向からＹ方向に向けて変動する。
【０００６】
このとき、第１の強磁性層２４及び第２の強磁性層２６から放出される電子が、第２の強磁性層２６と非磁性導電層２５との界面Ｇ及び第１の強磁性層２４と非磁性導電層２５との界面Ｊで散乱を起こすことによって磁気抵抗効果型素子２１の電気抵抗が変化し、この抵抗変化に基づく電圧変化により磁気ディスクからの漏れ磁界が検出され磁気ディスクの記録内容を読み出すことができる。
【０００７】
この磁気抵抗効果素子２１の電気抵抗は、第１，第２の強磁性層２４，２６の磁化が平行で逆向きな反平行な状態のときに、第１の強磁性層２４から第２の強磁性層２６へ向かって移動しようとする電子が、矢印ｅ８で示すように、第２の強磁性層２６と非磁性導電層２５との界面Ｇで散乱を起こすとともに、第２の強磁性層２６から第１の強磁性層２４へ向かって移動しようとする電子が、矢印ｅ９で示すように、第１の強磁性層２４と非磁性導電層２５との界面Ｊで散乱を起こすことによって最大となり、これら電子が散乱する界面数が多い程磁気抵抗効果素子２１の電気抵抗はより大きなものとなる。
【０００８】
また、第１，第２の強磁性層２４，２６の磁化が平行で同一方向を向いた状態のときには、第１の強磁性層２４から第２の強磁性層２６へ向かって移動しようとする電子のうちアップスピン伝導電子が、矢印ｅ１０で示すように、第２の強磁性層２６と非磁性導電層２５との界面Ｇで散乱を起こさずに第２の強磁性層２６内を通過して反強磁性層２３に向かって更に進み、第２の強磁性層２６から第１の強磁性層２４へ向かって移動しようとする電子のうちアップスピン伝導電子が、矢印ｅ９で示すように、第１の強磁性層２４と非磁性導電層２５との界面Ｊで散乱を起こすことによって磁気抵抗効果型素子２１の電気抵抗が最小となり、この電気抵抗は第１の強磁性層２４から第２の強磁性層２６へ向かって移動する電子（矢印ｅ１０）の移動距離が長い程より小さなものとなる。
【０００９】
【発明が解決しようとする課題】
磁気ディスク装置の高密度・大容量化に伴って、上述した従来の磁気抵抗効果型素子２１にあっては、その電気抵抗の最大値及び最小値をそれぞれＲｍａｘ，Ｒｍｉｎとしたときに、Ｒｍａｘを大きくしＲｍｉｎを小さくすることによって、（Ｒｍａｘ−Ｒｍｉｎ）／Ｒｍｉｎなる式で表される抵抗変化率を高め印加磁界検出感度を向上させることが要求されている。しかしながら、第１，第２の強磁性層２４，２６の磁化が反平行な状態における電子の散乱する界面数をこれ以上増やすことができず、また、第１，第２の強磁性層２４，２６の磁化が同一方向を向いた平行状態での、第１の強磁性層２４から第２の強磁性層２６へ向かって移動する電子（矢印ｅ１０）の移動距離は、最大でも２つの第１の強磁性層２４、１つの第２の強磁性層２６及び２つの非磁性導電層２５の総合膜厚Ｈ３よりも大きく設定することができず抵抗変化率を高めるのに限界があった。
【００１０】
本発明は上述した従来技術の事情に鑑みてなされたもので、その目的は、従来よりも抵抗変化率を高め印加磁界検出感度を向上させることができる磁気抵抗効果型素子を提供することにある。
【００１１】
【課題を解決するための手段】
上記目的を達成するために、本発明の磁気抵抗効果型素子は、対向して配置された第１の強磁性層および第２の強磁性層と、前記第１の強磁性層と前記第２の強磁性層との間に設けられた第１の非磁性導電層と、前記第１の強磁性層と磁気的に結合して、前記第１の強磁性層の磁化方向を固定する反強磁性層とをそれぞれ有する第１の積層体および第２の積層体を備え、
前記第１の積層体は、下から前記反強磁性層、前記第１の強磁性層、前記第１の非磁性導電層、前記第２の強磁性層がこの順番に積層されているとともに、前記第２の積層体は、下から前記第２の強磁性層、前記第１の非磁性導電層、前記第１の強磁性層、前記反強磁性層がこの順番に積層されており、
前記第１の積層体上に前記第２の積層体が導電硬磁性層を介して積層されて、前記第１の積層体における前記第２の強磁性層と前記導電硬磁性層との間に第２の非磁性導電層が設けられ、前記導電硬磁性層と前記第２の積層体における前記第２の強磁性層との間に第３の非磁性導電層が配設され、
前記導電硬磁性層の磁化方向が、それぞれの前記第１の強磁性層の磁化方向と同一方向に揃えられ、それぞれの前記第２の強磁性層は前記導電硬磁性層よりも保磁力が小さく、それぞれの前記第２の強磁性層の磁化が印加磁界に依存して自由に回転できるようにされており、
前記導電硬磁性層の比抵抗が、それぞれの前記反強磁性層の比抵抗よりも低いことを特徴とするものである。
【００１２】
また本発明の磁気抵抗効果型素子は、対向して配置された第１の強磁性層および第２の強磁性層と、前記第１の強磁性層と前記第２の強磁性層との間に設けられた第１の非磁性導電層と、前記第１の強磁性層と磁気的に結合して、前記第１の強磁性層の磁化方向を固定する反強磁性層とをそれぞれ有する第１の積層体および第２の積層体を備え、
前記第１の積層体は、下から前記反強磁性層、前記第１の強磁性層、前記第１の非磁性導電層、前記第２の強磁性層がこの順番に積層されているとともに、前記第２の積層体は、下から前記第２の強磁性層、前記第１の非磁性導電層、前記第１の強磁性層、前記反強磁性層がこの順番に積層されており、
前記第１の積層体上に前記第２の積層体が導電硬磁性層を介して積層されて、前記第１の積層体における前記第２の強磁性層と前記導電硬磁性層との間に第２の非磁性導電層が設けられ、前記導電硬磁性層と前記第２の積層体における前記第２の強磁性層との間に第３の非磁性導電層が配設され、
前記導電硬磁性層の磁化方向が、それぞれの前記第１の強磁性層の磁化方向と同一方向に揃えられ、それぞれの前記第２の強磁性層は前記導電硬磁性層よりも保磁力が小さく、それぞれの前記第２の強磁性層の磁化が印加磁界に依存して自由に回転できるようにされており、
それぞれの前記反強磁性層は、Ｘ−Ｍｎ合金（ここで元素ＸはＰｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上）で形成されて、前記導電硬磁性層が、ＣｏＰｔ，ＦｅＰｔの何れか１種により形成されていることを特徴とするものである。
【００１４】
また本発明の磁気抵抗効果型素子は、対向して配置された第１の強磁性層および第２の強磁性層と、前記第１の強磁性層と前記第２の強磁性層との間に設けられた第１の非磁性導電層と、前記第１の強磁性層と磁気的に結合して、前記第１の強磁性層の磁化方向を固定する反強磁性層とをそれぞれ有する第１の積層体および第２の積層体を備え、
前記第１の積層体は、下から前記反強磁性層、前記第１の強磁性層、前記第１の非磁性導電層、前記第２の強磁性層がこの順番に積層されているとともに、前記第２の積層体は、下から前記第２の強磁性層、前記第１の非磁性導電層、前記第１の強磁性層、前記反強磁性層がこの順番に積層されており、
前記第１の積層体上に前記第２の積層体が導電硬磁性層を介して積層されて、前記第１の積層体における前記第２の強磁性層と前記導電硬磁性層との間に第２の非磁性導電層が設けられ、前記導電硬磁性層と前記第２の積層体における前記第２の強磁性層との間に第３の非磁性導電層が配設され、
前記導電硬磁性層の磁化方向が、それぞれの前記第１の強磁性層の磁化方向と同一方向に揃えられ、それぞれの前記第２の強磁性層は前記導電硬磁性層よりも保磁力が小さく、それぞれの前記第２の強磁性層の磁化が印加磁界に依存して自由に回転できるようにされており、
それぞれの前記反強磁性層は、Ｘ−Ｍｎ−Ｘ’合金（ここで元素ＸはＰｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上で、元素Ｘ’はＮｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｂｅ，Ｂ，Ｃ，Ｎ，Ｍｇ，Ａｌ，Ｓｉ，Ｐ，Ｔｉ，Ｖ，Ｃｒ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｚｒ，Ｎｂ，Ｍｏ，Ａｇ，Ｃｄ，Ｓｎ，Ｈｆ，Ｔａ，Ｗ，Ｒｅ，Ａｕ，Ｐｂ及び希土類元素のうちの何れか１種または２種以上）で形成されて、前記導電硬磁性層が、ＣｏＰｔ，ＦｅＰｔの何れか１種により形成されていることを特徴とするものである。
【００１５】
また、上記構成において、前記第１の積層体、前記第２の積層体、前記導電硬磁性層、前記第２の非磁性導電層および前記第３の非磁性導電層に加えてさらに第３の積層体が設けられ、前記第３の積層体は、前記第２の非磁性導電層と前記導電硬磁性層との間に１つ以上配置されており、
前記第３の積層体は、下から導電硬磁性層、第３の非磁性導電層、第２の強磁性層、第１の非磁性導電層がこの順番に積層されて構成されていることを特徴とすることができる。
【００１６】
また、上記構成において、それぞれの前記第２の強磁性層の磁化方向を、前記第１の強磁性層および前記導電硬磁性層のそれぞれの磁化方向と交叉する方向に揃えるバイアス層を設けた構成とした。
【００１８】
また、上記構成において、それぞれの前記第２の強磁性層はＣｏ，Ｆｅ，Ｎｉの何れか１種または２種以上で形成されている構成とした。
【００１９】
【発明の実施の形態】
以下、本発明の磁気抵抗効果型素子の一実施形態を図１に基づいて説明する。
【００２０】
この磁気抵抗効果型素子１は、タンタル等の非磁性材料からなる下地層１１上に、反強磁性層２、第１の強磁性層３、第１の非磁性導電層４、第２の強磁性層５がこの順番に積層されてなる第１の積層体１３が形成され、この第１の積層体１３上に、第２の強磁性層５、第１の非磁性導電層４、第１の強磁性層３、反強磁性層２がこの順番に積層されてなる第２の積層体１４が、第２，第３の非磁性導電層６，７に挟まれた導電硬磁性層８を介して積層され、更に第２の積層体１４の反強磁性層２上にタンタル等の非磁性材料からなる保護層１２が形成されて、これら第１，第２の積層体１３，１４、第２，第３の非磁性導電層６，７、導電硬磁性層８、下地層１１及び保護層１２の両側に、電極層１０が形成された一対のバイアス層９が配設された構成となっている。
【００２１】
反強磁性層２は、第１の強磁性層３の磁化方向を固定する磁化方向固定層であって、Ｐｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上の元素とＭｎとを含む合金、または、Ｐｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上の元素とＭｎとＮｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｂｅ，Ｂ，Ｃ，Ｎ，Ｍｇ，Ａｌ，Ｓｉ，Ｐ，Ｔｉ，Ｖ，Ｃｒ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｚｒ，Ｎｂ，Ｍｏ，Ａｇ，Ｃｄ，Ｓｎ，Ｈｆ，Ｔａ，Ｗ，Ｒｅ，Ａｕ，Ｐｂ及び希土類元素のうちの何れか１種または２種以上の元素とを含む合金からなるものである。これらの合金からなる反強磁性層２は、耐熱性・耐食性に優れるという特徴を有している。
【００２２】
第１の強磁性層３は、例えば、Ｃｏ、ＦｅＮｉ合金、ＣｏＮｉＦｅ合金、ＣｏＦｅ合金、ＣｏＮｉ合金等で形成されてなるもので、第２の強磁性層５と対向して配置され、反強磁性層２との界面にて発生する交換結合による交換異方性磁界によって磁化され反強磁性層２と磁気的に結合しており、この結合により第１の強磁性層３の磁化方向が図示Ｙ方向（図１の紙面に向かう）に固定されている。
【００２３】
第１の非磁性導電層４は、Ｃｕ等の非磁性導電材料から形成されて、第１，第２の強磁性層３，５間に設けられている。
【００２４】
第２の強磁性層５は、Ｃｏ，Ｆｅ，Ｎｉの何れか一種、もしくは少なくともこれら２種以上の混合物からなる、例えば、ＦｅＮｉ合金、ＣｏＮｉＦｅ合金、ＣｏＦｅ合金、ＣｏＮｉ合金等で形成されてなるもので、導電硬磁性層８よりも保磁力が小さく設定され、バイアス層９から与えられるバイアス磁界の影響を受けて全体として単磁区化されており、第２の強磁性層５の磁化が第１の強磁性層３の磁化方向と交叉する図示Ｘ方向に揃えられ印加磁界に依存して自由に回転できるようにされている。
【００２５】
第２，第３の非磁性導電層６，７は、何れもＣｕ，Ａｕ，Ａｇ等の非磁性導電材料から形成されて、第２の非磁性導電層６が第１の積層体１３の第２の強磁性層５と導電硬磁性層８との間に設けられ、第３の非磁性導電層７が導電硬磁性層８と第２の積層体１４の第２の強磁性層５との間に配設されている。
【００２６】
導電硬磁性層８は、その磁化方向が自身の保磁力により第１の強磁性層３の磁化方向と同一方向（矢印Ｙ方向）に揃えられており、反強磁性層２と比較して遙かに比抵抗の低いＣｏＰｔ，ＦｅＰｔの何れか１種の合金により形成されて、後述するように、第１，第２の強磁性層３，５の磁化が平行で同一方向を向いた状態において第１の強磁性層３から第２の強磁性層５へ向かって移動しようとする電子が通過できるようにされている。
【００２７】
バイアス層９は、バイアス磁界を第２の強磁性層５に与え単磁区化して第２の強磁性層５の磁化をＸ方向に揃えるための永久磁石層であって、ＣｏＰｔ合金等から形成されてなっている。
【００２８】
電極層１０は、第１，第２の強磁性層３，５、第１，第２，第３の非磁性導電層４，６，７及び導電硬磁性層８に検出電流を流すためのものであり、Ａｕ，Ｗ，Ｃｒ，Ｔａ等の電気抵抗の小さい非磁性導電材料によって形成されている。
【００２９】
このように構成された磁気抵抗効果素子１は、例えば磁気ヘッドに適用されて磁気ディスク装置に組み込まれ、電極層１０からバイアス層９を介して第１，第２の強磁性層３，５、第１，第２，第３の非磁性導電層４，６，７、及び導電硬強磁性層８に検出電流が与えられ、図示Ｚ方向に回転走行する磁気ディスクからの漏れ磁界が印加磁界として図示Ｙ方向に沿って与えられると、第１，第２の積層体１３，１４の各第２の強磁性層５の磁化が図示Ｘ方向からＹ方向に向けて変動する。
【００３０】
このとき、第１，第２の強磁性層３，５及び導電硬磁性層８から放出される電子が、第１の強磁性層３と第１の非磁性導電層４との界面Ａ、第１の非磁性導電層４と第２の強磁性層５との界面Ｂ、第２の強磁性層５と第２の非磁性導電層６との界面Ｃ、第２の非磁性導電層６と導電硬磁性層８との界面Ｄ、第３の非磁性導電層７と第２の強磁性層５との界面Ｅ、及び導電硬磁性層８と第３の非磁性導電層７との界面Ｆの合計８つの界面で散乱を起こすことによって磁気抵抗効果型素子１の電気抵抗が変化し、この抵抗変化に基づく電圧変化により磁気ディスクからの漏れ磁界が検出され磁気ディスクの記録内容を読み出すことができる。
【００３１】
この磁気抵抗効果素子１の電気抵抗は、第１，第２の強磁性層３，５の磁化が平行で逆向きな反平行な状態のときに、第１の強磁性層３から第２の強磁性層５へ向かって移動しようとする電子が、矢印ｅ１で示すように、第２の強磁性層５と第１の非磁性導電層４との界面Ｂで散乱を起こすとともに、第２の強磁性層５から第１の強磁性層３へ向かって移動しようとする電子が、矢印ｅ２，ｅ３，ｅ４で示すように、第１の強磁性層３と第１の非磁性導電層４との界面Ａ、第２の非磁性導電層６と導電硬磁性層８との界面Ｄ、及び第３の非磁性導電層７と導電硬磁性層８との界面Ｆでそれぞれ散乱を起こし、更に、硬磁性層８から第２の強磁性層５に向かって移動しようとする電子が、矢印ｅ５，ｅ６で示すように、第２の強磁性層５と第２の非磁性導電層６との界面Ｃ、及び第２の強磁性層５と第３の非磁性導電層７との界面Ｅでそれぞれ散乱を起こすことによって最大となる。
【００３２】
また、第１，第２の強磁性層３，５の磁化が平行で同一方向を向いた状態のときには、第１の強磁性層３から第２の強磁性層５へ向かって移動しようとする電子のうちアップスピン伝導電子が、矢印ｅ７で示すように、第２の強磁性層５と第１の非磁性導電層４との界面Ｂで散乱を起こさずに第２の強磁性層５及び導電硬磁性層８内を通過して反強磁性層２に向かって更に進むことにより、磁気抵抗効果型素子１の電気抵抗が最小となる。
【００３３】
しかして、この磁気抵抗効果型素子１にあっては、第１，第２の強磁性層３，５の磁化が反平行な状態における電子の散乱する界面数を従来技術の４つに対し８つと大幅に増加させることができ、また、第１，第２の強磁性層３，５の磁化が同一方向を向いた平行状態での、第１の強磁性層３から第２の強磁性層５へ向かって移動する電子（矢印ｅ７）の移動距離が、最大で２つの第１の強磁性層３、２つの第２の強磁性層５、２つの第１の非磁性導電層４、第２，第３の非磁性導電層６，７及び導電硬磁性層８の総合膜厚Ｈ１となって従来技術よりも距離を延ばすことができるため、抵抗変化率を高めることができる。
【００３４】
また、導電硬磁性層８の磁化方向が第１の強磁性層３の磁化方向と同一方向に揃えられていることにより、第１の強磁性層３の磁化固定を不安定にしたり第２の強磁性層５の磁化変動を阻害する等の、導電硬磁性層８の磁化が第１，第２の強磁性層３，５に及ぼす悪影響を抑制することができ、図示Ｙ方向に印加磁界が磁気抵抗効果素子１に与えられたときに、その電気抵抗を第２の強磁性層５の磁化の変動によって確実に変化させることができるため、高感度で印加磁界（磁気ディスクからの漏れ磁界）を検出することができる。
【００３５】
また、第２の強磁性層５の磁化方向を第１の強磁性層３の磁化方向と交叉する方向に揃えるバイアス層９を設けたことにより、第２の強磁性層５を単磁区化することによって第２の強磁性層５に磁壁が出現するのを抑制することができ、これに起因するバルクハウゼンノイズの発生を防止することができる。
【００３６】
図２は本発明の他の応用例を示す図であって、この磁気抵抗効果型素子１５が上述した磁気抵抗効果型素子１と異なる点は、第２の非磁性導電層６と導電硬磁性層８との間に、導電硬磁性層８、第３の非磁性導電層７、第２の強磁性層５及び第１の非磁性導電層４を順次積層してなる第３の積層体１６を配設し、印加磁界が付与されたときに、第１，第２の積層体１３，１４の各第２の強磁性層５の磁化が変動するのに伴って第３の積層体１６の第２の強磁性層５の磁化が図示Ｘ方向からＹ方向に向けて変動するようにした点が異なるのみで、他は磁気抵抗効果型素子１と同様である。
【００３７】
このように構成された磁気抵抗効果型素子１５にあっては、第１，第２の強磁性層３，５及び導電硬磁性層８から放出される電子が散乱する界面数をより大幅に増やすことができ、また、第１，第２の強磁性層３，５の磁化が同一方向を向いた平行状態での、第１の強磁性層３から第２の強磁性層５へ向かって移動する電子の移動距離が、最大で２つの第１の強磁性層３、３つの第２の強磁性層５、３つの第１の非磁性導電層４、第２非磁性導電層６、２つの第３の非磁性導電層７及び２つの導電硬磁性層８の総合膜厚Ｈ２となって従来技術よりも距離を更に延ばすことができるため、抵抗変化率を一層高めることができる。
【００３８】
尚、この応用例では、第３の積層体１６を第２の非磁性導電層６と導電硬磁性層８との間に１つだけ配設した構成で説明したが、本発明はこれに限定されるものではなく、第２の非磁性導電層６と導電硬磁性層８との間に第３の積層体１６を２つ以上配設するようにしてもよく、このようにすると抵抗変化率をより一層高めることができる。
【００３９】
【発明の効果】
本発明は、以上説明したような形態で実施され、以下に記載されるような効果を奏する。
【００４０】
互いに対向して配置された第１，第２の強磁性層と、これら第１，第２の強磁性層間に設けられた第１の非磁性導電層と、前記第１の強磁性層と磁気的に結合して、前記第１の強磁性層の磁化方向を固定する反強磁性層とをそれぞれ有する第１，第２の積層体を備え、前記第１の積層体は、前記反強磁性層、第１の強磁性層、第１の非磁性導電層、第２の強磁性層がこの順番に積層されているとともに、前記第２の積層体は、前記第２の強磁性層、第１の非磁性導電層、第１の強磁性層、反強磁性層がこの順番に積層されており、前記第１の積層体上に前記第２の積層体が導電硬磁性層を介して積層されて、前記第１の積層体の第２の強磁性層と前記導電硬磁性層との間に第２の非磁性導電層が設けられ、前記導電硬磁性層と前記第２の積層体の第２の強磁性層との間に第３の非磁性導電層が配設され、前記第２の強磁性層の磁化が印加磁界に依存して自由に回転できるようにされているので、電子の散乱する界面数を大幅に増加させることができるとともに、電子の移動距離を延ばすことができるため、抵抗変化率を高めることができる。
【００４１】
前記導電硬磁性層、第３の非磁性導電層、第２の強磁性層、第１の非磁性導電層が順次積層されてなる第３の積層体が、前記第２の非磁性導電層と前記導電硬磁性層との間に１つ以上配設されているので、電子の散乱する界面数をより大幅に増加させることができるとともに、電子の移動距離を更に延ばすことができるため、抵抗変化率を一層高めることができる。
【００４２】
前記導電硬磁性層の磁化方向が、前記第１の強磁性層の磁化方向と同一方向に揃えられているので、前記第２の強磁性層５の磁化の確実な変動によって高感度で印加磁界を検出することができる。
【００４３】
前記第２の強磁性層の磁化方向を前記第１の強磁性層の磁化方向と交叉する方向に揃えるバイアス層を設けたので、前記第２の強磁性層を単磁区化することによって前記第２の強磁性層に磁壁が出現するのを抑制することができ、これに起因するバルクハウゼンノイズの発生を防止することができる。
【００４４】
前記反強磁性層はＸ−Ｍｎ合金で形成され、ここで元素ＸはＰｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上で形成されているので、耐熱性・耐食性に優れた磁気抵抗効果型素子を得ることができる。
【００４５】
前記反強磁性層はＸ−Ｍｎ−Ｘ’合金で形成され、ここで元素ＸはＰｔ，Ｒｕ，Ｐｄ，Ｒｈ，Ｉｒ，Ｏｓの何れか１種または２種以上で形成され、元素Ｘ’はＮｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｂｅ，Ｂ，Ｃ，Ｎ，Ｍｇ，Ａｌ，Ｓｉ，Ｐ，Ｔｉ，Ｖ，Ｃｒ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ，Ｇａ，Ｇｅ，Ｚｒ，Ｎｂ，Ｍｏ，Ａｇ，Ｃｄ，Ｓｎ，Ｈｆ，Ｔａ，Ｗ，Ｒｅ，Ａｕ，Ｐｂ及び希土類元素のうちの何れか１種または２種以上で形成されているので、耐熱性・耐食性に優れた磁気抵抗効果型素子を得ることができる。
【００４６】
前記導電硬磁性層は、ＣｏＰｔ，ＦｅＰｔの何れか１種により形成されているので、前記第１，第２の強磁性層の磁化が平行で同一方向を向いた状態において前記第１の強磁性層から前記第２の強磁性層へ向かって移動しようとする電子を確実に通過させることができる。
【００４７】
前記第２の強磁性層はＣｏ，Ｆｅ，Ｎｉの何れか１種または２種以上で形成され、前記導電硬磁性層よりも保磁力が小さく設定されているので、前記第２の強磁性層５の磁化が印加磁界によって確実に変動することによって高感度で印加磁界を検出することができる。
【図面の簡単な説明】
【図１】本発明の磁気抵抗効果型素子の断面図。
【図２】本発明の磁気抵抗効果型素子の応用例を説明するための断面図。
【図３】従来の磁気抵抗効果型素子の断面図。
【符号の説明】
１磁気抵抗効果型ヘッド
２反強磁性層
３第１の強磁性層
４第１の非磁性導電層
５第２の強磁性層
６第２の非磁性導電層
７第３の非磁性導電層
８導電硬磁性層
９バイアス層
１０電極層
１１下地層
１２保護層
１３第１の積層体
１４第２の積層体
１５磁気抵抗効果型素子
１６第３の積層体[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetoresistive element used for a magnetic head or the like, and more particularly to a magnetoresistive element utilizing a spin valve effect.
[0002]
[Prior art]
FIG. 3 is a view for explaining the prior art of this type of conventional magnetoresistive element, and this magnetoresistive element 21 is formed on a base layer 22 made of a nonmagnetic material such as tantalum in order. , An antiferromagnetic layer 23 made of PtMn alloy or the like, a first ferromagnetic layer 24 made of Co or the like, a nonmagnetic conductive layer 25 made of Cu or the like, and a second ferromagnetic layer 26 made of FeNi alloy or the like. On the second ferromagnetic layer 26, a nonmagnetic conductive layer 25, a first ferromagnetic layer 24, an antiferromagnetic layer 23, and a protective layer 27 made of a nonmagnetic material such as tantalum are sequentially laminated. A pair of bias layers 28 made of CoPt alloy or the like are disposed on both sides of these nine layers, and electrode layers 29 made of Au or the like are formed on the bias layer 28, respectively.
[0003]
The first ferromagnetic layer 24 is magnetized by an exchange anisotropic magnetic field due to exchange coupling generated at the interface with the antiferromagnetic layer 23, and the antiferromagnetic layer 23, the first ferromagnetic layer 24, Are coupled magnetically, and the magnetization direction of the first ferromagnetic layer 24 is fixed in the Y direction shown in the drawing (toward the paper surface of FIG. 3) by this coupling.
[0004]
Further, under the influence of the bias layer 28 magnetized in the X direction in the figure, the second ferromagnetic layer 26 is made into a single domain as a whole, and the magnetization is aligned in the X direction in the figure. Yes.
[0005]
The magnetoresistive effect element 21 configured as described above is applied to, for example, a magnetic head and incorporated in a magnetic disk device, and the first ferromagnetic layer 24 and the nonmagnetic conductive layer 25 from the electrode layer 29 through the bias layer 28. When a detection current is applied to the second ferromagnetic layer 26 and a leakage magnetic field from the magnetic disk rotating in the Z direction is applied as an applied magnetic field along the Y direction, the second ferromagnetic layer 26 is applied. The magnetization of fluctuates from the X direction to the Y direction in the figure.
[0006]
At this time, electrons emitted from the first ferromagnetic layer 24 and the second ferromagnetic layer 26 cause the interface G between the second ferromagnetic layer 26 and the nonmagnetic conductive layer 25 and the first ferromagnetic layer 24. The electric resistance of the magnetoresistive element 21 changes due to scattering at the interface J between the magnetic disk and the nonmagnetic conductive layer 25, and a magnetic field leaking from the magnetic disk is detected by a voltage change based on this resistance change, and recording on the magnetic disk is performed. The contents can be read.
[0007]
The electric resistance of the magnetoresistive element 21 is such that when the magnetizations of the first and second ferromagnetic layers 24 and 26 are parallel and opposite to each other in the antiparallel state, As shown by an arrow e8, electrons that move toward the ferromagnetic layer 26 are scattered at the interface G between the second ferromagnetic layer 26 and the nonmagnetic conductive layer 25, and the second ferromagnetic layer. As shown by an arrow e9, electrons that are moving from the first magnetic layer 26 toward the first ferromagnetic layer 24 are scattered at the interface J between the first ferromagnetic layer 24 and the nonmagnetic conductive layer 25 to maximize the electrons. Thus, the greater the number of interfaces where these electrons are scattered, the greater the electrical resistance of the magnetoresistive element 21.
[0008]
Further, when the magnetizations of the first and second ferromagnetic layers 24 and 26 are parallel and face the same direction, the first and second ferromagnetic layers 24 try to move from the first ferromagnetic layer 24 toward the second ferromagnetic layer 26. Of the electrons, up-spin conduction electrons pass through the second ferromagnetic layer 26 without scattering at the interface G between the second ferromagnetic layer 26 and the nonmagnetic conductive layer 25, as indicated by an arrow e10. As shown by the arrow e9, the up-spin conduction electrons among the electrons going further toward the antiferromagnetic layer 23 and moving from the second ferromagnetic layer 26 toward the first ferromagnetic layer 24 are By causing scattering at the interface J between the first ferromagnetic layer 24 and the nonmagnetic conductive layer 25, the electrical resistance of the magnetoresistive element 21 is minimized, and this electrical resistance is reduced from the first ferromagnetic layer 24 to the second. Of electrons moving toward the ferromagnetic layer 26 (arrow e10) Dynamic distance is smaller than enough long.
[0009]
[Problems to be solved by the invention]
With the increase in the density and capacity of the magnetic disk device, in the conventional magnetoresistive element 21 described above, when the maximum value and the minimum value of the electric resistance are Rmax and Rmin, respectively, It is required to increase the resistance change rate expressed by the equation (Rmax−Rmin) / Rmin and increase the applied magnetic field detection sensitivity by increasing Rmin and increasing Rmin. However, the number of interfaces where electrons are scattered in the state where the magnetizations of the first and second ferromagnetic layers 24 and 26 are antiparallel cannot be increased any more. The movement distance of the electrons (arrow e10) moving from the first ferromagnetic layer 24 toward the second ferromagnetic layer 26 in the parallel state in which the magnetizations of 26 are directed in the same direction is at most two first The ferromagnetic layer 24, the second ferromagnetic layer 26, and the two nonmagnetic conductive layers 25 cannot be set larger than the total thickness H3, and there is a limit to increasing the resistance change rate.
[0010]
The present invention has been made in view of the above-described prior art, and an object of the present invention is to provide a magnetoresistive element capable of increasing the resistance change rate and improving the applied magnetic field detection sensitivity as compared with the prior art. .
[0011]
[Means for Solving the Problems]
To achieve the above object, a magnetoresistive effect element of the present invention includes a first ferromagnetic layer and the second ferromagnetic layer disposed opposite said first ferromagnetic layer and the second antiferroelectric of the first non-magnetic conductive layer provided between the ferromagnetic layer, said first ferromagnetic layer and the magnetically bound to fix the magnetization direction of the first ferromagnetic layer A first laminated body and a second laminated body each having a magnetic layer;
Said first laminate from said lower antiferromagnetic layer, said first ferromagnetic layer, the first nonmagnetic conductive layer, the second ferromagnetic layer with are laminated in this order, the second laminate, wherein the lower second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, the antiferromagnetic layer are laminated in this order,
The second laminated body is laminated on the first laminated body via a conductive hard magnetic layer, and between the second ferromagnetic layer and the conductive hard magnetic layer in the first laminated body . a second non-magnetic conductive layer provided, the third non-magnetic conductive layer disposed between said second ferromagnetic layer in the second laminate and the conductive hard magnetic layer,
The magnetization direction of the conductive hard magnetic layer, aligned with the magnetization direction in the same direction of each of the first ferromagnetic layer, each of said second ferromagnetic layer has a smaller coercive force than said conductive hard magnetic layer , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
The specific resistance of the conductive hard magnetic layer is lower than the specific resistance of each of the antiferromagnetic layers .
[0012]
The magnetoresistive element of the present invention includes a first ferromagnetic layer and a second ferromagnetic layer disposed opposite to each other, and between the first ferromagnetic layer and the second ferromagnetic layer. A first nonmagnetic conductive layer provided on the first ferromagnetic layer, and an antiferromagnetic layer that is magnetically coupled to the first ferromagnetic layer and fixes a magnetization direction of the first ferromagnetic layer. Comprising a laminate of 1 and a second laminate,
The first stacked body includes the antiferromagnetic layer, the first ferromagnetic layer, the first nonmagnetic conductive layer, and the second ferromagnetic layer stacked in this order from below. In the second stacked body, the second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, and the antiferromagnetic layer are stacked in this order from the bottom,
The second laminated body is laminated on the first laminated body via a conductive hard magnetic layer, and between the second ferromagnetic layer and the conductive hard magnetic layer in the first laminated body. A second nonmagnetic conductive layer is provided, and a third nonmagnetic conductive layer is disposed between the conductive hard magnetic layer and the second ferromagnetic layer in the second laminate,
The magnetization direction of the conductive hard magnetic layer is aligned with the magnetization direction of each of the first ferromagnetic layers, and each of the second ferromagnetic layers has a smaller coercive force than the conductive hard magnetic layer. , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
Each of the antiferromagnetic layers is formed of an X-Mn alloy (wherein the element X is one or more of Pt, Ru, Pd, Rh, Ir, and Os), and the conductive hard magnetic layer Is formed of any one of CoPt and FePt.
[0014]
The magnetoresistive element of the present invention includes a first ferromagnetic layer and a second ferromagnetic layer disposed opposite to each other, and between the first ferromagnetic layer and the second ferromagnetic layer. A first nonmagnetic conductive layer provided on the first ferromagnetic layer, and an antiferromagnetic layer that is magnetically coupled to the first ferromagnetic layer and fixes a magnetization direction of the first ferromagnetic layer. Comprising a laminate of 1 and a second laminate,
The first stacked body includes the antiferromagnetic layer, the first ferromagnetic layer, the first nonmagnetic conductive layer, and the second ferromagnetic layer stacked in this order from below. In the second stacked body, the second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, and the antiferromagnetic layer are stacked in this order from the bottom,
The second laminated body is laminated on the first laminated body via a conductive hard magnetic layer, and between the second ferromagnetic layer and the conductive hard magnetic layer in the first laminated body. A second nonmagnetic conductive layer is provided, and a third nonmagnetic conductive layer is disposed between the conductive hard magnetic layer and the second ferromagnetic layer in the second laminate,
The magnetization direction of the conductive hard magnetic layer is aligned with the magnetization direction of each of the first ferromagnetic layers, and each of the second ferromagnetic layers has a smaller coercive force than the conductive hard magnetic layer. , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
Each of the antiferromagnetic layers is an X—Mn—X ′ alloy (wherein element X is one or more of Pt, Ru, Pd, Rh, Ir, Os, and element X ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Any one or more of Cd, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements), and the conductive hard magnetic layer is any one of CoPt and FePt. It is characterized by being formed by.
[0015]
Further, in the above structure, in addition to the first stacked body, the second stacked body, the conductive hard magnetic layer, the second nonmagnetic conductive layer, and the third nonmagnetic conductive layer, a third layer is further added. A laminate is provided, and one or more third laminates are disposed between the second nonmagnetic conductive layer and the conductive hard magnetic layer;
The third laminate is composed of a conductive hard magnetic layer, a third nonmagnetic conductive layer, a second ferromagnetic layer, and a first nonmagnetic conductive layer stacked in this order from the bottom. Can be a feature.
[0016]
In the above configuration, a bias layer is provided that aligns the magnetization direction of each of the second ferromagnetic layers with the direction intersecting with the magnetization directions of the first ferromagnetic layer and the conductive hard magnetic layer. It was.
[0018]
It was also in the above-described structure, each of said second ferromagnetic layer is Co, Fe, and configuration that is formed by any one or more and Ni.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the magnetoresistive element of the present invention will be described with reference to FIG.
[0020]
The magnetoresistive element 1 includes an antiferromagnetic layer 2, a first ferromagnetic layer 3, a first nonmagnetic conductive layer 4, and a second strong layer on an underlayer 11 made of a nonmagnetic material such as tantalum. A first laminated body 13 is formed by laminating the magnetic layers 5 in this order. On the first laminated body 13, the second ferromagnetic layer 5, the first nonmagnetic conductive layer 4, the first laminated body 13 are formed. The second laminated body 14 in which the ferromagnetic layer 3 and the antiferromagnetic layer 2 are laminated in this order forms the conductive hard magnetic layer 8 sandwiched between the second and third nonmagnetic conductive layers 6 and 7. Further, a protective layer 12 made of a nonmagnetic material such as tantalum is formed on the antiferromagnetic layer 2 of the second laminated body 14, and the first and second laminated bodies 13, 14, 2, a pair of bias layers 9 each having an electrode layer 10 formed on both sides of the third nonmagnetic conductive layers 6 and 7, the conductive hard magnetic layer 8, the underlayer 11 and the protective layer 12. And it has a configuration.
[0021]
The antiferromagnetic layer 2 is a magnetization direction fixed layer that fixes the magnetization direction of the first ferromagnetic layer 3, and is one or more elements of Pt, Ru, Pd, Rh, Ir, and Os. And an alloy containing Mn, or one or more elements of Pt, Ru, Pd, Rh, Ir, Os and Mn and Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, It consists of an alloy containing one or more elements of Pb and rare earth elements. The antiferromagnetic layer 2 made of these alloys is characterized by excellent heat resistance and corrosion resistance.
[0022]
The first ferromagnetic layer 3 is made of, for example, Co, FeNi alloy, CoNiFe alloy, CoFe alloy, CoNi alloy or the like, and is disposed to face the second ferromagnetic layer 5 and is antiferromagnetic. It is magnetized by an exchange anisotropic magnetic field due to exchange coupling generated at the interface with the layer 2 and is magnetically coupled to the antiferromagnetic layer 2, and the magnetization direction of the first ferromagnetic layer 3 is indicated by Y in this coupling. It is fixed in the direction (toward the page of FIG. 1).
[0023]
The first nonmagnetic conductive layer 4 is made of a nonmagnetic conductive material such as Cu and is provided between the first and second ferromagnetic layers 3 and 5.
[0024]
The second ferromagnetic layer 5 is made of any one of Co, Fe, and Ni, or a mixture of at least two of these, for example, formed of FeNi alloy, CoNiFe alloy, CoFe alloy, CoNi alloy or the like. Thus, the coercive force is set to be smaller than that of the conductive hard magnetic layer 8 and is made into a single magnetic domain as a whole under the influence of the bias magnetic field applied from the bias layer 9, and the magnetization of the second ferromagnetic layer 5 is the first. The ferromagnetic layer 3 is aligned in the X direction, which intersects with the magnetization direction of the ferromagnetic layer 3, and can rotate freely depending on the applied magnetic field.
[0025]
The second and third nonmagnetic conductive layers 6 and 7 are both made of a nonmagnetic conductive material such as Cu, Au, or Ag, and the second nonmagnetic conductive layer 6 is the first laminate 13. Between the second ferromagnetic layer 5 and the conductive hard magnetic layer 8, and the third nonmagnetic conductive layer 7 is formed between the conductive hard magnetic layer 8 and the second ferromagnetic layer 5 of the second stacked body 14. It is arranged in between.
[0026]
The conductive hard magnetic layer 8 has its magnetization direction aligned in the same direction as the magnetization direction of the first ferromagnetic layer 3 (arrow Y direction) by its coercive force. In the state in which the magnetization of the first and second ferromagnetic layers 3 and 5 is parallel and oriented in the same direction, as will be described later, formed of an alloy of any one of CoPt and FePt having a low specific resistance. Electrons that attempt to move from the first ferromagnetic layer 3 toward the second ferromagnetic layer 5 can pass therethrough.
[0027]
The bias layer 9 is a permanent magnet layer for applying a bias magnetic field to the second ferromagnetic layer 5 to form a single magnetic domain so as to align the magnetization of the second ferromagnetic layer 5 in the X direction, and is formed of a CoPt alloy or the like. It has become.
[0028]
The electrode layer 10 is for passing a detection current through the first and second ferromagnetic layers 3, 5, the first, second, third nonmagnetic conductive layers 4, 6, 7 and the conductive hard magnetic layer 8. And formed of a nonmagnetic conductive material having a small electric resistance, such as Au, W, Cr, Ta.
[0029]
The magnetoresistive effect element 1 configured in this way is applied to, for example, a magnetic head and incorporated in a magnetic disk device, and the first and second ferromagnetic layers 3, 5 through the bias layer 9 from the electrode layer 10, A detection current is applied to the first, second and third nonmagnetic conductive layers 4, 6, 7 and the conductive hard ferromagnetic layer 8, and a leakage magnetic field from a magnetic disk rotating in the Z direction in the figure is applied as the applied magnetic field. When given along the Y direction in the figure, the magnetization of each second ferromagnetic layer 5 of the first and second stacked bodies 13 and 14 varies from the X direction to the Y direction in the figure.
[0030]
At this time, electrons emitted from the first and second ferromagnetic layers 3 and 5 and the conductive hard magnetic layer 8 are converted into the interface A between the first ferromagnetic layer 3 and the first nonmagnetic conductive layer 4, the first The interface B between the first nonmagnetic conductive layer 4 and the second ferromagnetic layer 5, the interface C between the second ferromagnetic layer 5 and the second nonmagnetic conductive layer 6, and the second nonmagnetic conductive layer 6 Interface D between the conductive hard magnetic layer 8, interface E between the third nonmagnetic conductive layer 7 and the second ferromagnetic layer 5, and interface F between the conductive hard magnetic layer 8 and the third nonmagnetic conductive layer 7 The electrical resistance of the magnetoresistive element 1 changes due to scattering at a total of eight interfaces, and a leakage magnetic field from the magnetic disk is detected by a voltage change based on this resistance change, and the recorded content of the magnetic disk can be read out. it can.
[0031]
The electric resistance of the magnetoresistive effect element 1 is such that when the magnetizations of the first and second ferromagnetic layers 3 and 5 are parallel and opposite to each other in an antiparallel state, As shown by the arrow e1, electrons that move toward the ferromagnetic layer 5 cause scattering at the interface B between the second ferromagnetic layer 5 and the first nonmagnetic conductive layer 4, and the second As shown by arrows e2, e3, e4, the electrons that are moving from the ferromagnetic layer 5 toward the first ferromagnetic layer 3 have the first ferromagnetic layer 3, the first nonmagnetic conductive layer 4, and the like. Scattering at the interface A, the interface D between the second nonmagnetic conductive layer 6 and the conductive hard magnetic layer 8, and the interface F between the third nonmagnetic conductive layer 7 and the conductive hard magnetic layer 8, respectively. As shown by arrows e5 and e6, the electrons that are moving from the hard magnetic layer 8 toward the second ferromagnetic layer 5 are in contact with the second ferromagnetic layer 5 and the second ferromagnetic layer 5. Interface C between the nonmagnetic conductive layer 6, and the maximum by causing scattering, respectively at the interface E between the second ferromagnetic layer 5 and the third non-magnetic conductive layer 7.
[0032]
Further, when the magnetizations of the first and second ferromagnetic layers 3 and 5 are parallel and face the same direction, they tend to move from the first ferromagnetic layer 3 toward the second ferromagnetic layer 5. Of the electrons, up-spin conduction electrons do not scatter at the interface B between the second ferromagnetic layer 5 and the first nonmagnetic conductive layer 4 as indicated by an arrow e7, and the second ferromagnetic layer 5 and By passing further through the conductive hard magnetic layer 8 toward the antiferromagnetic layer 2, the electric resistance of the magnetoresistive element 1 is minimized.
[0033]
Thus, in this magnetoresistive element 1, the number of interfaces in which electrons are scattered in the state where the magnetizations of the first and second ferromagnetic layers 3 and 5 are antiparallel is 8 as compared with the conventional four. The first ferromagnetic layer 3 to the second ferromagnetic layer in a parallel state in which the magnetizations of the first and second ferromagnetic layers 3 and 5 are directed in the same direction. The moving distance of the electrons (arrow e7) moving toward 5 is a maximum of two first ferromagnetic layers 3, two second ferromagnetic layers 5, two first nonmagnetic conductive layers 4, Since the total film thickness H1 of the second and third nonmagnetic conductive layers 6 and 7 and the conductive hard magnetic layer 8 is obtained and the distance can be increased as compared with the prior art, the rate of resistance change can be increased.
[0034]
Further, since the magnetization direction of the conductive hard magnetic layer 8 is aligned with the same direction as the magnetization direction of the first ferromagnetic layer 3, the magnetization fixed of the first ferromagnetic layer 3 becomes unstable or the second The adverse effect of the magnetization of the conductive hard magnetic layer 8 on the first and second ferromagnetic layers 3 and 5, such as inhibiting the magnetization fluctuation of the ferromagnetic layer 5, can be suppressed, and the applied magnetic field is When given to the magnetoresistive effect element 1, its electric resistance can be reliably changed by the fluctuation of the magnetization of the second ferromagnetic layer 5, so that the applied magnetic field (leakage magnetic field from the magnetic disk) is highly sensitive. Can be detected.
[0035]
Further, by providing a bias layer 9 that aligns the magnetization direction of the second ferromagnetic layer 5 with the direction intersecting with the magnetization direction of the first ferromagnetic layer 3, the second ferromagnetic layer 5 is made into a single magnetic domain. As a result, the appearance of the domain wall in the second ferromagnetic layer 5 can be suppressed, and the occurrence of Barkhausen noise due to this can be prevented.
[0036]
FIG. 2 is a diagram showing another application example of the present invention. The magnetoresistive effect element 15 is different from the magnetoresistive effect element 1 described above in that the second nonmagnetic conductive layer 6 and the conductive hard magnetism are used. Between the layer 8, a third laminated body 16 is formed by sequentially laminating the conductive hard magnetic layer 8, the third nonmagnetic conductive layer 7, the second ferromagnetic layer 5, and the first nonmagnetic conductive layer 4. And when the applied magnetic field is applied, the magnetization of the second ferromagnetic layer 5 of the first and second stacked bodies 13 and 14 varies with the fluctuation of the magnetization of the third stacked body 16. The second ferromagnetic layer 5 is the same as the magnetoresistive element 1 except that the magnetization of the second ferromagnetic layer 5 is changed from the X direction to the Y direction in the drawing.
[0037]
In the magnetoresistive element 15 configured as described above, the number of interfaces where electrons emitted from the first and second ferromagnetic layers 3 and 5 and the conductive hard magnetic layer 8 are scattered is greatly increased. And the first and second ferromagnetic layers 3 and 5 move from the first ferromagnetic layer 3 toward the second ferromagnetic layer 5 in a parallel state in which the magnetizations are in the same direction. The movement distance of the electrons to be transmitted is a maximum of two first ferromagnetic layers 3, three second ferromagnetic layers 5, three first nonmagnetic conductive layers 4, second nonmagnetic conductive layers 6, Since the total film thickness H2 of the third nonmagnetic conductive layer 7 and the two conductive hard magnetic layers 8 is obtained, the distance can be further increased as compared with the prior art, and the resistance change rate can be further increased.
[0038]
In this application example, only one third laminated body 16 is disposed between the second nonmagnetic conductive layer 6 and the conductive hard magnetic layer 8, but the present invention is not limited to this. Instead, two or more third laminated bodies 16 may be disposed between the second nonmagnetic conductive layer 6 and the conductive hard magnetic layer 8, and in this way, the rate of change in resistance is increased. Can be further increased.
[0039]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0040]
First and second ferromagnetic layers disposed opposite to each other, a first nonmagnetic conductive layer provided between the first and second ferromagnetic layers, the first ferromagnetic layer and the magnetic layer And first and second laminated bodies each having an antiferromagnetic layer that fixes the magnetization direction of the first ferromagnetic layer, and the first laminated body includes the antiferromagnetic layer. A layer, a first ferromagnetic layer, a first nonmagnetic conductive layer, and a second ferromagnetic layer are stacked in this order, and the second stacked body includes the second ferromagnetic layer, the second ferromagnetic layer, One nonmagnetic conductive layer, a first ferromagnetic layer, and an antiferromagnetic layer are laminated in this order, and the second laminated body is laminated on the first laminated body via a conductive hard magnetic layer. A second nonmagnetic conductive layer is provided between the second ferromagnetic layer and the conductive hard magnetic layer of the first stacked body, and the conductive hard magnetic layer and the second stacked layer are provided. Since a third nonmagnetic conductive layer is disposed between the second ferromagnetic layer and the second ferromagnetic layer, the magnetization of the second ferromagnetic layer can be freely rotated depending on the applied magnetic field. The number of interfaces where electrons are scattered can be greatly increased, and the moving distance of electrons can be extended, so that the rate of change in resistance can be increased.
[0041]
A third stacked body in which the conductive hard magnetic layer, the third nonmagnetic conductive layer, the second ferromagnetic layer, and the first nonmagnetic conductive layer are sequentially stacked includes the second nonmagnetic conductive layer. Since one or more conductive layers are disposed between the conductive hard magnetic layer, the number of interfaces where electrons are scattered can be greatly increased, and the distance traveled by electrons can be further extended. The rate can be further increased.
[0042]
Since the magnetization direction of the conductive hard magnetic layer is aligned with the same direction as the magnetization direction of the first ferromagnetic layer, the applied magnetic field can be applied with high sensitivity by the reliable fluctuation of the magnetization of the second ferromagnetic layer 5. Can be detected.
[0043]
Since the bias layer for aligning the magnetization direction of the second ferromagnetic layer with the direction intersecting with the magnetization direction of the first ferromagnetic layer is provided, the second ferromagnetic layer is converted into a single magnetic domain. It is possible to suppress the appearance of a domain wall in the second ferromagnetic layer, and to prevent the occurrence of Barkhausen noise due to this.
[0044]
The antiferromagnetic layer is formed of an X—Mn alloy, and the element X is formed of any one or more of Pt, Ru, Pd, Rh, Ir, and Os. Can be obtained.
[0045]
The antiferromagnetic layer is formed of an X—Mn—X ′ alloy, where the element X is formed of one or more of Pt, Ru, Pd, Rh, Ir, and Os, and the element X ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, A magnetoresistive element having excellent heat resistance and corrosion resistance because it is formed of any one or more of Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements. Can be obtained.
[0046]
Since the conductive hard magnetic layer is formed of one of CoPt and FePt, the first and second ferromagnetic layers are parallel to each other and have the same magnetization direction. Electrons that attempt to move from the layer toward the second ferromagnetic layer can be reliably passed.
[0047]
The second ferromagnetic layer is formed of one or more of Co, Fe, and Ni and has a coercive force set smaller than that of the conductive hard magnetic layer. Thus, the applied magnetic field can be detected with high sensitivity.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a magnetoresistive element of the present invention.
FIG. 2 is a cross-sectional view for explaining an application example of the magnetoresistive element of the present invention.
FIG. 3 is a cross-sectional view of a conventional magnetoresistive element.
[Explanation of symbols]
1 magnetoresistive head 2 antiferromagnetic layer 3 first ferromagnetic layer 4 first nonmagnetic conductive layer 5 second ferromagnetic layer 6 second nonmagnetic conductive layer 7 third nonmagnetic conductive layer 8 Conductive hard magnetic layer 9 Bias layer 10 Electrode layer 11 Underlayer 12 Protective layer 13 First laminated body 14 Second laminated body 15 Magnetoresistive element 16 Third laminated body

Claims

A first ferromagnetic layer and the second ferromagnetic layer disposed opposite to the first non-magnetic conductive layer disposed between the first ferromagnetic layer and the second ferromagnetic layer And a first laminated body and a second laminated body each having an antiferromagnetic layer that is magnetically coupled to the first ferromagnetic layer and fixes the magnetization direction of the first ferromagnetic layer. Prepared,
Said first laminate from said lower antiferromagnetic layer, said first ferromagnetic layer, the first nonmagnetic conductive layer, the second ferromagnetic layer with are laminated in this order, the second laminate, wherein the lower second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, the antiferromagnetic layer are laminated in this order,
The second laminated body is laminated on the first laminated body via a conductive hard magnetic layer, and between the second ferromagnetic layer and the conductive hard magnetic layer in the first laminated body . a second non-magnetic conductive layer provided, the third non-magnetic conductive layer disposed between said second ferromagnetic layer in the second laminate and the conductive hard magnetic layer,
The magnetization direction of the conductive hard magnetic layer, aligned with the magnetization direction in the same direction of each of the first ferromagnetic layer, each of said second ferromagnetic layer has a smaller coercive force than said conductive hard magnetic layer , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
A magnetoresistive element having a specific resistance of the conductive hard magnetic layer lower than that of each of the antiferromagnetic layers .

First and second ferromagnetic layers disposed opposite to each other, and a first nonmagnetic conductive layer provided between the first ferromagnetic layer and the second ferromagnetic layer And a first laminated body and a second laminated body each having an antiferromagnetic layer that is magnetically coupled to the first ferromagnetic layer and fixes the magnetization direction of the first ferromagnetic layer. Prepared,
The first stacked body includes the antiferromagnetic layer, the first ferromagnetic layer, the first nonmagnetic conductive layer, and the second ferromagnetic layer stacked in this order from below. In the second stacked body, the second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, and the antiferromagnetic layer are stacked in this order from the bottom,
The second laminated body is laminated on the first laminated body via a conductive hard magnetic layer, and between the second ferromagnetic layer and the conductive hard magnetic layer in the first laminated body. A second nonmagnetic conductive layer is provided, and a third nonmagnetic conductive layer is disposed between the conductive hard magnetic layer and the second ferromagnetic layer in the second laminate,
The magnetization direction of the conductive hard magnetic layer is aligned with the magnetization direction of each of the first ferromagnetic layers, and each of the second ferromagnetic layers has a smaller coercive force than the conductive hard magnetic layer. , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
Each of the antiferromagnetic layers is formed of an X-Mn alloy (wherein the element X is one or more of Pt, Ru, Pd, Rh, Ir, and Os), and the conductive hard magnetic layer Is formed of any one of CoPt and FePt.

First and second ferromagnetic layers disposed opposite to each other, and a first nonmagnetic conductive layer provided between the first ferromagnetic layer and the second ferromagnetic layer And a first laminated body and a second laminated body each having an antiferromagnetic layer that is magnetically coupled to the first ferromagnetic layer and fixes the magnetization direction of the first ferromagnetic layer. Prepared,
The first stacked body includes the antiferromagnetic layer, the first ferromagnetic layer, the first nonmagnetic conductive layer, and the second ferromagnetic layer stacked in this order from below. In the second stacked body, the second ferromagnetic layer, the first nonmagnetic conductive layer, the first ferromagnetic layer, and the antiferromagnetic layer are stacked in this order from the bottom,
The second laminate is laminated on the first laminate via a conductive hard magnetic layer, and the first laminate A second nonmagnetic conductive layer is provided between the second ferromagnetic layer and the conductive hard magnetic layer in the stacked body, and the second strong layer in the conductive hard magnetic layer and the second stacked body. A third nonmagnetic conductive layer is disposed between the magnetic layer and
The magnetization direction of the conductive hard magnetic layer is aligned with the magnetization direction of each of the first ferromagnetic layers, and each of the second ferromagnetic layers has a smaller coercive force than the conductive hard magnetic layer. , The magnetization of each of the second ferromagnetic layers can be freely rotated depending on the applied magnetic field,
Each of the antiferromagnetic layers is an X—Mn—X ′ alloy (wherein element X is one or more of Pt, Ru, Pd, Rh, Ir, Os, and element X ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Any one or more of Cd, Sn, Hf, Ta, W, Re, Au, Pb and rare earth elements), and the conductive hard magnetic layer is any one of CoPt and FePt. A magnetoresistive effect element formed by:

In addition to the first laminate, the second laminate, the conductive hard magnetic layer, the second nonmagnetic conductive layer, and the third nonmagnetic conductive layer, a third laminate is further provided. One or more of the third laminated bodies are disposed between the second nonmagnetic conductive layer and the conductive hard magnetic layer,
The third laminate is composed of a conductive hard magnetic layer, a third nonmagnetic conductive layer, a second ferromagnetic layer, and a first nonmagnetic conductive layer stacked in this order from the bottom. 4. The magnetoresistive element according to claim 1, wherein

Claims the magnetization direction of each of the second ferromagnetic layer, characterized in that a bias layer for aligning the direction crossing the respective magnetization directions of the first ferromagnetic layer and the conductive hard magnetic layer The magnetoresistive element according to any one of 1 to 4 .

Each of said second ferromagnetic layer is Co, Fe, magnetoresistive element according to any one of claims 1 to 5, characterized in that it is formed by any one or more of Ni .