John Leighton Read

US Patent:

8576519, Nov 5, 2013

Filed:

Oct 11, 2012

Appl. No.:

13/649245

Inventors:

- Amsterdam, NL
Jeffrey R. Childress - San Jose CA, US
Young-suk Choi - Los Gatos CA, US
John Creighton Read - San Jose CA, US

Assignee:

HGST Netherlands B.V. - Amsterdam

International Classification:

G11B 5/39

US Classification:

360324, 3603242

Abstract:

A current-perpendicular-to-the-plane magnetoresistive sensor has magnetic damping material located adjacent either or both of the sensor side edges and back edge to reduce the effect of spin transfer torque. The damping material may be Pt, Pd, Os, or a rare earth metal from the 15 lanthanoid elements. The damping material may be an ultrathin layer in contact with the sensor edges. An insulating layer is deposited on the damping layer and isolates the sensor's ferromagnetic biasing layer from the damping layer. Instead of being a separate layer, the damping material may be formed adjacent the sensor edges by being incorporated into the material of the insulating layer.

US Patent:

8617644, Dec 31, 2013

Filed:

Mar 8, 2012

Appl. No.:

13/415808

Inventors:

Matthew J. Carey - San Jose CA, US
Shekar B Chandrashekariaih - San Jose CA, US
Jeffrey R. Childress - San Jose CA, US
Young-suk Choi - Los Gatos CA, US
John Creighton Read - San Jose CA, US

Assignee:

HGST Netherlands B.V. - Amsterdam

International Classification:

G11B 5/84

US Classification:

427130, 360324

Abstract:

A method for making a current-perpendicular-to the-plane giant magnetoresistance (CPP-GMR) sensor with a Heusler alloy pinned layer on the sensor's Mn-containing antiferromagnetic pinning layer uses two annealing steps. A layer of a crystalline non-Heusler alloy ferromagnetic material, like Co or CoFe, is deposited on the antiferromagnetic pinning layer and a layer of an amorphous X-containing ferromagnetic alloy, like a CoFeBTa layer, is deposited on the Co or CoFe crystalline layer. After a first in-situ annealing of the amorphous X-containing ferromagnetic alloy, the Heusler alloy pinned layer is deposited on the amorphous X-containing ferromagnetic layer and a second high-temperature annealing step is performed to improve the microstructure of the Heusler alloy pinned layer.

US Patent:

20130052484, Feb 28, 2013

Filed:

Aug 31, 2011

Appl. No.:

13/222827

Inventors:

Jeffrey R. Childress - San Jose CA, US
John C. Read - San Jose CA, US
Neil Smith - San Jose CA, US

International Classification:

G11B 5/33
B05D 5/12

US Classification:

428816, 427123, 427125

Abstract:

A method and apparatus for increasing the electrical resistivity and corrosion resistance of the material forming a spacer layer in current-perpendicular-to-the-plane (CPP) giant magnetoresistive (GMR) sensors. The increased resistivity of the spacer layer, and thus, the CPP-GMR sensor permits a larger voltage across the sensor and a higher signal-to-noise ratio. The increased corrosion resistance of the spacer layer minimizes the effects of exposing the spacer layer to corrosive materials during fabrication. For example, adding tin to silver to form a metallic alloy spacer layer increases the corrosion resistance of the spacer layer and the electrical resisitivity of the CPP-GMR sensor relative to a spacer layer consisting solely of silver. The Ag—Sn alloy permits a larger current to flow through the sensor, which increases the signal-to-noise ratio.

US Patent:

20130070371, Mar 21, 2013

Filed:

Sep 21, 2011

Appl. No.:

13/238838

Inventors:

Jeffrey R. Childress - San Jose CA, US
David Patrick Druist - Santa Clara CA, US
John Creighton Read - San Jose CA, US

International Classification:

G11B 5/60
H05K 7/02

US Classification:

3602354, 361807

Abstract:

An electrical lapping guide (ELG) for the fabrication of an air-bearing slider used in a magnetic recording disk drive is formed of a different material than the magnetoresistive (MR) read head or sensor so as to have both a high electrical resistivity and a substantially higher etch rate. When the ELG and MR sensor are etched simultaneously to form their respective back edges, the ELG will have a sharp well-defined non-tapered wall at the back edge. The ELG has a film thickness close to but generally thinner than that of the MR sensor, and a sheet resistance to generally match the resistance measurement capability of the lapping tool. The preferred material for the ELG is an alloy comprising silver (Ag) and one or more of Sn, Ge and zinc Zn.

US Patent:

43464165, Aug 24, 1982

Filed:

Feb 29, 1980

Appl. No.:

6/126129

Inventors:

Charles M. Riggle - Acton MA
John D. Read - Monument CO
William B. Noe - Concord MA
Richard Winfrey - Boxborough MA
Christopher A. Pollard - Monument CO
Frank W. Bernett - Colorado Springs CO

Assignee:

Digital Equipment Corporation - Maynard MA

International Classification:

G11B 2102
G11B 555

US Classification:

360106

Abstract:

A rotary actuator assembly for positioning read/write heads in disk drive mass storage systems. The actuator assembly includes an actuator motor and one or more actuator arms secured thereto. The motor provides rotary motion of the arms, to move the heads. The stator magnet of the motor is an electromagnet wound on an arcuate core; a pair of elongate permanent magnets are attached to the rotor member, for coaction with the stator magnet. The rotor member has a U-shaped cross sectional area in a plane perpendicular to its axis of rotation; the permanent magnets are fixed to the outside, bottom corners of the U and the actuator arms are mounted across the open end of the U. The rotor is of a very small radius, to minimize inertia. The permanent magnets have a flat face facing the stator, with a channel running longitudinally down the middle, to minimize flux density variations in the permanent magnet-coil gap. The rotor balances the arm relative to the rotor's axis.

US Patent:

43630561, Dec 7, 1982

Filed:

Feb 29, 1980

Appl. No.:

6/126024

Inventors:

Charles M. Riggle - Acton MA
Christopher A. Pollard - Monument CO
John D. Read - Monument CO

Assignee:

Digital Equipment Corporation - Maynard MA

International Classification:

G11B 5012

US Classification:

360 98

Abstract:

A housing (1-10) for a disk (1-12) used in a "Winchester"-type disk mass information storage unit in a data processing system. The housing is symmetrical about the plane of the disk, and supports the disk spindle (2-33) on both sides of the disk. The housing includes two substantially identical members (1-16, 17) fitted together in a clamshell-type arrangement. The housing includes a housing extension (1-26) for receiving and supporting the read/write heads (1-14) and actuator (1-15) therefor from both ends thereof. The members forming the housing are preferably thin walled castings, and may include fins (1-104) to dissipate heat or to enhance the housing's mechanical rigidity.

US Patent:

20200411754, Dec 31, 2020

Filed:

Jun 26, 2019

Appl. No.:

16/453372

Inventors:

- San Jose CA, US
Lei WAN - San Jose CA, US
John READ - San Jose CA, US
Zhaoqiang BAI - San Jose CA, US
Mac APODACA - San Jose CA, US

International Classification:

H01L 45/00
H01L 27/24

Abstract:

A phase change memory cell includes a first electrode, a second electrode located over the first electrode, a vertical pillar structure located between the first and second electrodes, the pillar structure containing a first phase change memory (PCM) material portion, a second PCM material portion and an intermediate electrode located between the first PCM material portion and the second PCM material portion, and a resistive liner containing a first segment electrically connected in parallel to the first PCM material portion between the first electrode and the intermediate electrode, and a second segment electrically connected in parallel to the second PCM material portion between the intermediate electrode and the second electrode. The first PCM material portion has a different electrical resistance than the second PCM material portion, and the first segment of the resistive liner has a different electrical resistance than the second segment of the resistive liner.

US Patent:

20180108391, Apr 19, 2018

Filed:

Dec 18, 2017

Appl. No.:

15/844769

Inventors:

- San Jose CA, US
John C. READ - San Jose CA, US

International Classification:

G11C 11/16
H01L 43/08

Abstract:

Embodiments disclosed herein generally relate to a multilayer magnetic device, and specifically to a spin-torque transfer magnetoresistive random access memory (STT-MRAM) device which provides for a reduction in the amount of current required for switching individual bits. As such, a polarizing reference layer consisting of a synthetic antiferromagnet (SAF) structure with an in-plane magnetized ferromagnet film indirectly exchange coupled to a magnetic film with perpendicular magnetic anisotropy (PMA) is disclosed. By tuning the exchange coupling strength and the PMA, the layers of the SAF may both be canted such that either may be used as a tilted polarizer for either an in-plane free layer or a free layer with PMA.