Thai Huu Le

US Patent:

6992866, Jan 31, 2006

Filed:

Aug 31, 2004

Appl. No.:

10/931315

Inventors:

Matthew Joseph Carey - San Jose CA, US
Eric Edward Fullerton - Morgan Hill CA, US
Bruce Alvin Gurney - San Rafael CA, US
Thai Le - San Jose CA, US
Stefan Maat - San Jose CA, US
Philip Milton Rice - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 5/39

US Classification:

36032411

Abstract:

An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

US Patent:

7116532, Oct 3, 2006

Filed:

Nov 9, 2004

Appl. No.:

10/985195

Inventors:

Matthew Joseph Carey - San Jose CA, US
Eric Edward Fullerton - Morgan Hill CA, US
Bruce Alvin Gurney - San Rafael CA, US
Thai Le - San Jose CA, US
Stefan Maat - San Jose CA, US
Philip Milton Rice - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 5/39

US Classification:

36032411

Abstract:

An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

US Patent:

20020154456, Oct 24, 2002

Filed:

Apr 24, 2001

Appl. No.:

09/841942

Inventors:

Matthew Carey - San Jose CA, US
Eric Fullerton - Morgan Hill CA, US
Bruce Gurney - San Rafael CA, US
Thai Le - San Jose CA, US
Stefan Maat - San Jose CA, US
Philip Rice - San Jose CA, US

International Classification:

G11B005/39

US Classification:

360/324110, 360/324120, 360/324200

Abstract:

An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.

US Patent:

20050036244, Feb 17, 2005

Filed:

Sep 27, 2004

Appl. No.:

10/951397

Inventors:

Matthew Carey - San Jose CA, US
Eric Fullerton - Morgan Hill CA, US
Bruce Gurney - San Rafael CA, US
Thai Le - San Jose CA, US
Stefan Maat - San Jose CA, US
Philip Rice - San Jose CA, US

International Classification:

G11B005/127
G11B005/33

US Classification:

360324120

Abstract:

An exchange-coupled magnetic structure includes a ferromagnetic layer, a coercive ferrite layer, such as cobalt-ferrite, for biasing the magnetization of the ferromagnetic layer, and an oxide underlayer, such as cobalt-oxide, in proximity to the coercive ferrite layer. The oxide underlayer has a lattice structure of either rock salt or a spinel and exhibits no magnetic moment at room temperature. The underlayer affects the structure of the coercive ferrite layer and therefore its magnetic properties, providing increased coercivity and enhanced thermal stability. As a result, the coercive ferrite layer is thermally stable at much smaller thicknesses than without the underlayer. The exchange-coupled structure is used in spin valve and magnetic tunnel junction magnetoresistive sensors in read heads of magnetic disk drive systems. Because the coercive ferrite layer can be made as thin as 1 nm while remaining thermally stable, the sensor satisfies the narrow gap requirements of high recording density systems.