Min Li

US Patent:

6388847, May 14, 2002

Filed:

Feb 1, 2000

Appl. No.:

09/495348

Inventors:

Cheng T. Horng - San Jose CA
Min Li - Fremont CA
Ru-Ying Tong - San Jose CA
Rong-Fu Xiao - Fremont CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

36032411, 2960314

Abstract:

A specular spin valve structure that is more robust than currently available specular spin valves is described. The improved stability is achieved by a using a modified pinned layer that is a laminate of three layersâa layer nickel-chromium, between about 3 and 4 Angstroms thick, sandwiched between two layers of cobalt-iron. A key requirement is that the cobalt-iron layer closest to the copper separation layer must be about twice as thick as the other cobalt-iron layer. A process for manufacturing this structure is also disclosed.

US Patent:

6392853, May 21, 2002

Filed:

Jan 24, 2000

Appl. No.:

09/489973

Inventors:

Min Li - Fremont CA
Simon H. Liao - Fremont CA
Cheng T. Horng - San Jose CA
Youfeng Zheng - Sunnyvale CA
Ru-Ying Tong - San Jose CA
Kochan Ju - Fremont CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

36032412, 360314, 428692, 428332, 428611

Abstract:

The giant magnetoresistance (GMR) effect includes a contribution that is due to anisotropic magnetoresistance (AMR). Unfortunately the AMR effect tends to degrade the peak-to-peak signal asymmetry. Additionally, a high AMR/GMR ratio causes a larger signal asymmetry variation. It is therefor desirable to reduce both the AMR contribution as well as the AMR/GMR ratio. This has been achieved by modifying the free layer through the insertion of an extra layer of a highly resistive or insulating material at approximately mid thickness level. This layer is from 3 to 15 Angstroms thick and serves to reduce the Anisotropic Magneto-resistance contribution to the total magneto-resistance of the device. This reduces the GMR contribution only slightly but cuts the AMR/GMR ratio in half, thereby improving cross-track asymmetry and signal linearity.

US Patent:

6396671, May 28, 2002

Filed:

Mar 15, 2000

Appl. No.:

09/525670

Inventors:

Cheng T. Horng - San Jose CA
Kochan Ju - Fremont CA
Min Li - Fremont CA
Simon H. Liao - Fremont CA
Ku-Ying Tong - San Jose CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

3603241, 2960314, 36032412

Abstract:

A spin valve structure, and method for manufacturing it, are described. The valve is subject to only small bias point shifts by sense current fields while at the same time has good GMR characteristics. This is achieved by introducing a layer of about 15 Angstroms of ruthenium between the seed layer and the free layer. This acts as an effective bias control layer with the added benefit of providing interfaces (to both the seed and the free layer) that are highly favorable to specular reflection of the conduction electrons. The HCP crystal structure of this ruthenium layer also improves the crystalline quality of the free layer thereby improving its performance with respect to the GMR ratio.

US Patent:

6466418, Oct 15, 2002

Filed:

Feb 11, 2000

Appl. No.:

09/502035

Inventors:

Cheng T. Horng - San Jose CA
Min Li - Fremont CA
Simon H. Liao - Fremont CA
Ru-Ying Tong - San Jose CA
Chyu Jiuh Torng - Pleasanton CA
Rongfu Xiao - Fremont CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

36032412, 2960314

Abstract:

A method for forming a specularly reflecting bottom spin valve magnetoresistive (SVMR) sensor element with continuous spacer exchange hard bias and a specularly reflecting bottom spin valve magnetoresistive (SVMR) sensor element fabricated according to that method. To practice the method, there is provided a substrate upon which is formed a seed layer, upon which is formed an antiferromagnetic pinning layer, upon which is formed a ferromagnetic pinned layer, upon which is formed a non-magnetic spacer layer, upon which is formed a ferromagnetic free layer, upon which is formed a specularly reflecting and capping layer. The width of the sensor element is defined by a pair of conducting leads aligned upon a pair of continuous spacer exchange hard bias layers.

US Patent:

6517896, Feb 11, 2003

Filed:

Aug 7, 2000

Appl. No.:

09/633768

Inventors:

Cheng T. Horng - San Jose CA
Min Li - Fremont CA
Ru-Ying Tong - San Jose CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

B05D 512

US Classification:

427123, 4271263, 4271264, 427404, 4274191, 4274192, 4273761, 427128

Abstract:

A high performance specular free layer bottom spin valve is disclosed. This structure made up the following layers: NiCr/MnPt/CoFe/Ru/CoFe/Cu/free layer/Cu/Ta or TaO/Al O. A key feature is that the free layer is made of a very thin CoFe/NiFe composite layer. Experimental data confirming the effectiveness of this structure is provided, together with a method for manufacturing it and, additionally, its longitudinal bias leads.

US Patent:

6522507, Feb 18, 2003

Filed:

May 12, 2000

Appl. No.:

09/570017

Inventors:

Cheng T. Horng - San Jose CA
Min Li - Fremont CA
Ru-Ying Tong - San Jose CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

36032412, 2960314, 148108

Abstract:

A method for fabricating a single top spin valve head that is capable of reading ultra-high density recordings. Said top spin valve has a CoFe free layer for high GMR ratio, which is grown on a NiCr/Ru layer to provide better magnetic properties and has a ferromagnetically coupled CoFe/NiCr/CoFe laminated pinned layer for thermal stability and robustness.

US Patent:

6581272, Jun 24, 2003

Filed:

Jan 4, 2002

Appl. No.:

10/037812

Inventors:

Min Li - Fremont CA
Simon H. Liao - Fremont CA
Masashi Sano - Nagano, JP
Kiyoshi Noguchi - Nagano, JP
Kochan Ju - Fremont CA
Cheng T. Horng - San Jose CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 5127

US Classification:

2960314, 2960308, 2960315, 36032411, 36032412, 427127, 427130, 427131

Abstract:

A method for forming a bottom spin valve sensor having a synthetic antiferromagnetic pinned (SyAP) layer, antiferromagnetically coupled to a pinning layer, in which one of the layers of the SyAP is formed as a three layer lamination that contains a specularly reflecting oxide layer of FeTaO. The sensor formed according to this method has an extremely high GMR ratio and exhibits good pinning strength.

US Patent:

6614630, Sep 2, 2003

Filed:

Apr 23, 2001

Appl. No.:

09/839960

Inventors:

Cheng Horng - San Jose CA
Ru-Ying Tong - San Jose CA
Min Li - Fremont CA

Assignee:

Headway Technologies, Inc. - Milpitas CA

International Classification:

G11B 539

US Classification:

36032412

Abstract:

A method for fabricating a specularly reflecting top spin valve read head with an ultra-thin free layer that is capable of reading ultra-high density recordings. This top spin valve has a composite CoFeâNiFe free layer that is formed on a composite RuâCu buffer layer which provides lattice-matching to the free layer as well as enhanced specular reflection. The free layer is pinned by a synthetic antiferromagnetic pinning layer. The resulting fabrication has a conducting lead layer formed over it that defines the sensor trackwidth and a magnetic bias layer formed outside of the conducting lead layer.