Magnetoresistive effect element, magnetic head and magnetic reproducing apparatus

• US 20030011945A1
• Filed: 06/21/2002
• Published: 01/16/2003
• Est. Priority Date: 06/22/2001
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yoshikawa, Masatoshi, Yuasa, Hiromi, Sahashi, Masashi, Koui, Katsuhiko, Iwasaki, Hitoshi
• Granted Patent: US 7,218,483 B2
• Time in Patent Office: Days
• US Class Current: 360/324.1
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3929 Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding
• CPC Class Codes: H01F 10/1936 Half-metallic, e.g. epitaxial CrO2 or NiMnSb films
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3259 Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H01F 10/3281 only by use of asymmetry of the magnetic film pair itself, i.e. so-called pseudospin valve [PSV] structure, e.g. NiFe/Cu/Co
• CPC Class Codes: H01F 41/305 applying the spacer or adjusting its interface, e.g. in order to enable particular effect different from exchange coupling
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A spin valve type magnetoresistive effect element for vertical electric conduction includes a magnetoresistive effect film in which a resistance adjustment layer made of a material containing conductive carriers not more than 10²²/cm³ is inserted. Thus the resistance value of a portion in change of spin-relied conduction is raised to an adequate value, thereby to increase the resistance variable amount.

Claims

1. A magnetoresistive effect element comprising:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer, and a resistance adjustment layer interposed between said magnetization-pinned layer and said magnetization free layer and made of a material containing a quantity of conductive carriers not more than 10²²/cm³; and

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film.

2. A magnetoresistive effect element according to claim 1, wherein said resistance adjustment layer is interposed at least in one of a location between said magnetization-pinned layer and said nonmagnetic metallic intermediate layer and a location between said magnetization free layer and said nonmagnetic metallic intermediate layer.

3. A magnetoresistive effect element according to claim 1, wherein said resistance adjustment layer is interposed in said nonmagnetic metallic intermediate layer.

4. A magnetoresistive effect element according to claim 1, wherein said resistance adjustment layer is made of a semiconductor or a semimetal.

5. A magnetoresistive effect element according to claim 1, wherein said resistance adjustment layer contains as its major component one material selected from the group consisting of C, Si, Ge, AlN, GaN, InN, AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, InSb, ZnO, β

-ZnS, ZnSe, ZnTe, CdS, CdTe, HgTe, α

-SiC, β

-SiC, PbS, PbSe, PbTe, SnTe, CuInSe₂, FeSi_2.43, β

-FeSi₂, MnSi_1.72, CrSi₂, (Cr_1-xMn_x)Si₂, Mg₂Si, BaSi₂, ReSi_1.75, RuSi_{3, OsSi2} and Ir₃Si₅.

6. A magnetoresistive effect element according to claim 1, wherein said resistance adjustment layer contains as its major component one material selected from the group consisting of graphite, As, Sb, Bi, HgTe, HgSe, CoSi, (Co_1-xFe_x)Si, (Co_1-xNi_x)Si, (Co_1-xMn_x)Si, (Co_1-xCr_x)Si and FeS.

7. A magnetoresistive effect element according to claim 1, wherein a thickness of said resistance adjustment layer is equal to or less than 1 nm.

8. A magnetoresistive effect element according to claim 1, further comprising an insulating layer located adjacent to said resistance adjustment layer and made of an oxide.

9. A magnetoresistive effect element according to claim 8, wherein said insulating layer is located nearer to a supply side of electrons forming said sense current with respect to said resistance adjustment layer.

10. A magnetoresistive effect element comprising:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, and a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer;

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film,

wherein said nonmagnetic intermediate layer is a resistance adjustment layer made of a material containing conductive carriers not more than 10²²/cm³.

11. A magnetoresistive effect element according to claim 10, wherein said resistance adjustment layer is made of a semiconductor or a semimetal.

12. A magnetoresistive effect element according to claim 10, wherein said resistance adjustment layer contains as its major component one material selected from the group consisting of C, Si, Ge, AlN, GaN, InN, AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs, InSb, ZnO, β

-ZnS, ZnSe, ZnTe, CdS, CdTe, HgTe, α

-SiC, β

-SiC, PbS, PbSe, PbTe, SnTe, CuInSe₂, FeSi_2.43, β

-FeSi₂, MnSi_1.72, CrSi₂, (Cr_1-xMn_x)Si₂, Mg₂Si, BaSi₂, ReSi_1.75, RuSi₃, OsSi₂ and Ir₃Si₅.

13. A magnetoresistive effect element according to claim 10, wherein said resistance adjustment layer contains as its major component one material selected from the group consisting of graphite, As, Sb, Bi, HgTe, HgSe, CoSi, (Co_1-xFe_x)Si, (Co_1-xNi_x)Si, (Co_1-xMn_x)Si, (Co_1-xCr_x)Si and FeS.

14. A magnetoresistive effect element according to claim 10, wherein a thickness of said resistance adjustment layer is equal to or less than 3 nm.

15. A magnetoresistive effect element according to claim 10, further comprising an insulating layer located adjacent to said resistance adjustment layer and made of an oxide.

16. A magnetoresistive effect element according to claim 15, wherein said insulating layer is located nearer to a supply side of electrons forming said sense current with respect to said resistance adjustment layer.

17. A magnetic head comprising a magnetoresistive effect element having:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer, and a resistance adjustment layer interposed between said magnetization-pinned layer and said magnetization free layer and made of a material containing a quantity of conductive carriers not more than 10²²/cm³; and

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film.

18. A magnetic head comoprising a magnetoresistive effect element having:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, and a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer;

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film,

wherein said nonmagnetic intermediate layer is a resistance adjustment layer made of a material containing conductive carriers not more than 10²²/cm³.

19. A magnetic reproducing apparatus which reads information magnetically recorded in a magnetic recording medium,

said magnetic reproducing apparatus comprising a magnetoresistive effect element having:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer, and a resistance adjustment layer interposed between said magnetization-pinned layer and said magnetization free layer and made of a material containing a quantity of conductive carriers not more than 10²²/cm³; and

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film.

20. A magnetic reproducing apparatus which reads information magnetically recorded in a magnetic recording medium,

said magnetic reproducing apparatus comprising a magnetoresistive effect element having:

a magnetoresistive effect film including a magnetization-pinned layer having a magnetic film whose direction of magnetization is pinned substantially in one direction, a magnetization free layer having a magnetic film whose direction of magnetization varies in response to an external magnetic field, and a nonmagnetic metallic intermediate layer interposed between said magnetization-pinned layer and said magnetization free layer;

a pair of electrodes electrically coupled to said magnetoresistive effect film to supply a sense current substantially vertically of the film plane of said magnetoresistive effect film,

wherein said nonmagnetic intermediate layer is a resistance adjustment layer made of a material containing conductive carriers not more than 10²²/cm³.