Jing Zhang

US Patent:

6447935, Sep 10, 2002

Filed:

Nov 23, 1999

Appl. No.:

09/447944

Inventors:

Jing Zhang - San Jose CA
Ningjia Zhu - Cupertino CA
Yiming Huai - Pleasanton CA
Amritpal Singh Rana - Union City CA
Wenjie Chen - Cupertino CA

Assignee:

Read-Rite Corporation - Fremont CA

International Classification:

G11B 566

US Classification:

428692, 428694 R, 428694 TS, 428694 TM, 428900, 427128, 427129, 427130, 360113, 360125, 360126, 338 32 R, 324252

Abstract:

A method and system for providing a spin valve for use in a magnetoresistive head is disclosed. The method and system include providing a synthetic pinned layer, a nonmagnetic spacer layer, and a free layer. The free layer has a first magnetization canted from a first direction by a first angle. The nonmagnetic spacer layer is disposed between the free layer and the synthetic pinned layer. The synthetic pinned layer has a second magnetization in a second direction. The second direction is canted from a third direction that is transverse to the first direction by a second angle. The second magnetization is substantially orthogonal to the first magnetization.

US Patent:

6934129, Aug 23, 2005

Filed:

Sep 30, 2002

Appl. No.:

10/260896

Inventors:

Jinqiu Zhang - Fremont CA, US
Jing Zhang - San Jose CA, US
Yiming Huai - Pleasanton CA, US
Lifan Chen - Fremont CA, US

Assignee:

Western Digital (Fremont), Inc. - Fremont CA

International Classification:

G11B005/39

US Classification:

360322

Abstract:

Magnetoresistive (MR) sensors are disclosed that have leads that overlap a MR structure and distribute current to and from the MR structure so that the current is not concentrated in small portions of the leads, alleviating the problems mentioned above. For example, the leads can be formed of a body-centered cubic (bcc) form of tantalum, combined with gold or other highly conductive materials. For the situation in which a thicker bcc tantalum layer covers a highly conductive gold layer, the tantalum layer protects the gold layer during MR structure etching, so that the leads can have broad layers of electrically conductive material for connection to MR structures. The broad leads also conduct heat better than the read gap material that they replace, further reducing the temperature at the connection between the leads and the MR structure.

US Patent:

6943993, Sep 13, 2005

Filed:

Feb 11, 2003

Appl. No.:

10/364799

Inventors:

Thomas Young Chang - Menlo Park CA, US
Yingjian Chen - Fremont CA, US
Jing Zhang - San Jose CA, US
Heng Gong - Layton UT, US

Assignee:

Western Digital (Fremont), Inc. - Lake Forest CA

International Classification:

G11B005/39

US Classification:

360319

Abstract:

Side shield structures magnetically shielding a read sensor to block side reading of tracks on a magnetic media. The read heads include bottom and top magnetic shield layers, a read sensor or magnetically sensitive element between the bottom and top magnetic shield layers, and a side shield assembly formed of magnetically shielding material positioned between the bottom and top magnetic shield layers and adjacent at least a portion of the read sensor. In current-in-plane embodiments, the side shield assembly includes a pair of side shields of magnetically shielding material adjacent a lower portion of the read sensor formed on a lower read gap. In current-perpendicular-to-plane embodiments, the side shield assembly includes a pair of side shields extending from the bottom magnetic shield adjacent lower sides of the read sensor and/or a pair of side shields extending from the top magnetic shield adjacent upper sides of the read sensor.

US Patent:

6989972, Jan 24, 2006

Filed:

Sep 30, 2002

Appl. No.:

10/261119

Inventors:

Kroum Stoev - Fremont CA, US
Mathew Gibbons - Livermore CA, US
Francis Liu - Fremont CA, US
Bogdan M. Simion - Pleasanton CA, US
Aparna C. Vadde - Fremont CA, US
Jing Zhang - San Jose CA, US
Yiming Huai - Pleasanton CA, US
Marcos M. Lederman - San Francisco CA, US

Assignee:

Western Digital (Fremont), Inc. - Fremont CA

International Classification:

G11B 5/39

US Classification:

360322

Abstract:

Magnetoresistive (MR) sensors have leads that overlap a MR structure and distribute current to the MR structure so that the current is not concentrated in small portions of the leads. An electrically resistive capping layer can be formed between the leads and the MR structure to distribute the current. The leads can include resistive layers and conductive layers, the resistive layers having a thickness-to-resistivity ratio that is greater than that of each of the conductive layers. The resistive layers may protect the conductive layers during MR structure etching, so that the leads have broad layers of electrically conductive material for connection to MR structures. The broad leads conduct heat better than the read gap material that they replace, further reducing the temperature at the connection between the leads and the MR structure.

US Patent:

7050934, May 23, 2006

Filed:

Nov 24, 2004

Appl. No.:

10/997173

Inventors:

Yong Shen - Saratoga CA, US
Jing Zhang - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G06F 11/30

US Classification:

702179, 702182, 702 33, 702 34, 702 81, 702 84, 714 33, 714 47, 714 48, 716 4

Abstract:

Embodiments of the invention provide methods for enhancing the downstream product yield without significantly affecting the yield of components from which downstream products are made or enhancing yield of the components without significantly affecting the downstream product yield and performance. In one embodiment, a method comprises obtaining a failure rate of the downstream manufacturing process as a function of each of a plurality of component performance parameters of the current manufacturing process of the component; optimizing weighted factors based on correlation between the current manufacturing process of the component and the downstream product, the weight factors each corresponding to one of the plurality of component performance parameters; and calculating figure of merits (FOM) with respect to the plurality of component performance parameters of the current manufacturing process of the component, the FOM including the weighted factors.

US Patent:

7292401, Nov 6, 2007

Filed:

Mar 14, 2006

Appl. No.:

11/376660

Inventors:

Yong Shen - Saratoga CA, US
Jing Zhang - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 15/18

US Classification:

360 69

Abstract:

A system and method for determining head-disk contact (HDC) in a disk drive uses the signal from the magnetoresistive (MR) read head and does not require the presence of magnetic transitions on the disk. The method thus has application in head-disk testers or “spin stands” to facilitate the design and testing of slider-suspension assemblies and fly-height actuators, as well as in disk drives to take corrective action before HDC and/or to control fly-height actuators. The invention is also a magnetic recording disk drive that has a fly-height actuator and a low-pass filter and comparator circuit for the MR signal. When the output of the filter exceeds a threshold the comparator circuit output indicates the onset of HDC. The comparator circuit output is input to a digital processor or controller. When the controller determines the onset of HDC or that HDC has occurred, it generates a control signal that can be used to cause the disk drive to take corrective action.

US Patent:

7411754, Aug 12, 2008

Filed:

Aug 8, 2006

Appl. No.:

11/463307

Inventors:

Mike X. Wang - San Jose CA, US
Jing Zhang - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 5/09

US Classification:

360 46, 360 31

Abstract:

A method for operating a tester for testing heads and disks of a magnetic recording disk drive during manufacturing calculates the readback signal amplitude asymmetry in the frequency domain without the need for measurement in the time domain with a peak detection channel. The tester first signals the write head to write a first pattern on the disk to generate a readback signal with positive pulses. The read head then detects this first recorded pattern and sends the readback signal to a spectrum analyzer connected to the tester. The tester then signals the write head to write a second pattern on the disk to generate a readback signal with negative pulses. The read head then detects this second recorded pattern and sends the readback signal to the spectrum analyzer. The spectrum analyzer measures the amplitudes of the first and second readback signals in the frequency domain using a bandpass filter. A controller in the tester calculates readback signal amplitude asymmetry from the measured amplitudes of the first and second readback signals.

US Patent:

7529050, May 5, 2009

Filed:

Feb 20, 2007

Appl. No.:

11/708941

Inventors:

Yong Shen - Saratoga CA, US
Mike X. Wang - San Jose CA, US
Jing Zhang - San Jose CA, US

Assignee:

Hitachi Global Storage Technologies Netherlands B.V. - Amsterdam

International Classification:

G11B 5/455
G11B 27/36

US Classification:

360 31, 360 75

Abstract:

One embodiment in accordance with the invention is a method for measuring a track width for a magnetic recording head comprising writing a first track and a second track on a disk at two different positions. Note that the first track is written at a frequency plus a frequency shift value while the second track is written at the frequency minus the frequency shift value.