Byron H Lengsfield

20060263643, Nov 23, 2006

May 19, 2005

11/134746

Eric Fullerton - Morgan Hill CA, US
Olav Hellwig - Berlin, DE
Byron Lengsfield - Gilroy CA, US
David Margulies - Salinas CA, US

G11B 5/66

428828100

The invention uses an upper and lower magnetic layer of a laminated magnetic layer structure that includes an AF spacer layer that results in weak antiferromagnetic coupling of the magnetic layers that is insufficient to cause either of the layers to switch so that the magnetic orientations of the two ferromagnetic layers remain parallel. An advantage of the invention is that the AF-coupling tends to anti-correlate the noise in the two layers. The weak AF coupling according to the invention is believed to act at the transition boundaries in the media to cause some of the noise domains to be oriented antiparallel and the noise to be less correlated than would be the case without the AF coupling and thereby to achieve improved SNR.

20060269792, Nov 30, 2006

May 24, 2005

11/135703

Eric Fullerton - Morgan Hill CA, US
Byron Lengsfield - Gilroy CA, US
David Margulies - Salinas CA, US

G11B 5/66

428828000, 428828100, 428829000

A perpendicular magnetic recording disk has an antiferromagnetically-coupled (AFC) recording layer (RL) comprised of lower and upper ferromagnetic layers, each having a hexagonal-close-packed (hcp) crystalline structure and perpendicular magnetic anisotropy, separated by an antiferromagnetically (AF) coupling layer, wherein the lower ferromagnetic layer (LFM) has substantially higher magnetic permeability than the upper ferromagnetic layer (UFM). The AFC RL is located on an actual exchange break layer (EBL) that separates the AFC RL from the disk's soft magnetic underlayer (SUL). The LFM functions as part of an “effective” exchange break layer (EBL) that also includes the actual EBL and the AF-coupling layer, thereby allowing the actual EBL to be made as thin as possible. The hcp LFM promotes the growth of the hcp UFM in the same way the actual EBL does so that its thickness contributes to the thickness necessary to grow the hcp UFM. The effective EBL appears to be magnetically “thin” during the write process and magnetically “thick” during the readback process.

20070115583, May 24, 2007

Nov 23, 2005

11/286026

Christian Bonhote - San Jose CA, US
Quang Le - San Jose CA, US
Byron Lengsfield - Gilroy CA, US
Jui-Lung Li - San Jose CA, US
Scott MacDonald - San Jose CA, US
Petrus Van Der Heijden - San Jose CA, US

G11B 5/33

360126000, 360317000

A magnetic write head for perpendicular magnetic recording, the write head having a magnetic write pole configured with a cross section as viewed from the ABS that has a trailing portion with substantially vertical side walls and a leading portion formed with a taper that becomes narrower as it extends toward the leading edge. The write pole provides for excellent write field strength by providing sufficient cross section near the trailing edge to avoid magnetic saturation of the pole tip. The parallel side walls of the trailing portion also provide for excellent track width control during manufacture of the write head. The tapered portion of the write head, which starts some distance away from the trailing edge, prevents skew related adjacent track writing when the actuator that holds the write head is at its innermost or outermost travel extensions.

20070212574, Sep 13, 2007

Mar 9, 2006

11/372295

Andreas Berger - San Jose CA, US
Hoa Do - Fremont CA, US
Eric Fullerton - Morgan Hill CA, US
Yoshihiro Ikeda - San Jose CA, US
Byron Lengsfield - Gilroy CA, US
Natacha Supper - Campbell CA, US

G11B 5/66

428828000, 428830000, 428836200, 428828100, 360135000

A perpendicular magnetic recording medium has an “exchange-spring” type magnetic recording layer (RL) formed of two ferromagnetic layers with substantially similar anisotropy fields that are ferromagnetically exchange-coupled by a nonmagnetic or weakly ferromagnetic coupling layer. Because the write head produces a larger magnetic field and larger field gradient at the upper portion of the RL, while the field strength decreases further inside the RL, the upper ferromagnetic layer can have a high anisotropy field. The high field and field gradient near the top of the RL, where the upper ferromagnetic layer is located, reverses the magnetization of the upper ferromagnetic layer, which then assists in the magnetization reversal of the lower ferromagnetic layer. Because both ferromagnetic layers in this exchange-spring type RL have a high anisotropy field, the thermal stability of the medium is not compromised. The medium shows improved writability, i.e., a low switching field, as well as lower intrinsic media noise, over a medium with a conventional single-layer RL.

20070247748, Oct 25, 2007

Apr 24, 2006

11/379858

Yoshihiro Ikeda - San Jose CA, US
Byron Lengsfield - Gilroy CA, US
James Olson - Santa Cruz CA, US
Petrus VanDerHeijden - San Jose CA, US

HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V. - San Jose CA

G11B 5/147

360126000

A perpendicular magnetic recording data storage system combines a perpendicular medium that has a thin low-magnetic-permeability or “soft” underlayer (SUL) with a recording head that has a trailing shield (TS) with a thick throat height, i.e., a thickness in a direction orthogonal to the recording layer of the medium. The SUL is thin enough and has a low enough magnetic permeability to become saturated in a region beneath the trailing gap of the head during writing, but the throat height of the TS is thick enough to prevent the TS from becoming magnetically saturated during writing. The magnetic saturation of the SUL during writing changes the magnetic reluctance such that more of the magnetic flux going through the SUL changes direction (“field undershoot”) and goes to the TS. If the permeability of the SUL is so low (e.g., close to unity) that the SUL does not magnetically saturate, field undershoot may still occur because the reluctance from the SUL to the TS is still smaller than the reluctance from the SUL to the return pole (RP). Field undershoot enables a high write field gradient, which results in narrower magnetic transitions.

20080057349, Mar 6, 2008

Sep 6, 2006

11/470310

Andreas Klaus Berger - San Jose CA, US
Hoa Van Do - Fremont CA, US
Yoshihiro Ikeda - San Jose CA, US
Byron Hassberg Lengsfield - Gilroy CA, US
Hal Jervis Rosen - Los Gatos CA, US
Kentaro Takano - San Jose CA, US
Min Xiao - Los Gatos CA, US

G11B 5/65

4288362

A high performance perpendicular media with optimal exchange coupling between grains has improved thermal stability, writeability, and signal-to-noise ratio in a selected range of allowable intergranular exchange between the grains for high performing media. The writeability and byte error rate of a TaOmedia are demonstrated to be substantially better than that of other designs.

20080070065, Mar 20, 2008

Sep 14, 2006

11/532055

Andreas Klaus Berger - San Jose CA, US
Hoa Van Do - Fremont CA, US
Byron Hassberg Lengsfield - Gilroy CA, US
Natacha F. Supper - Campbell CA, US

HITACHI GLOBAL STORAGE TECHNOLOGIES NETHERLANDS B.V. - San Jose CA

G11B 5/66
G11B 5/82

4288281, 428829, 360135

A perpendicular magnetic recording system and medium has a multilayered recording layer that includes an exchange-spring structure and a ferromagnetic lateral coupling layer (LCL). The exchange-spring structure is made up of two ferromagnetically exchange-coupled magnetic layers (MAG and MAG), each with perpendicular magnetic anisotropy. MAG and MAG are either in direct contact with one another or have a coupling layer (CL) located between them. The LCL is located in direct contact with MAG and mediates intergranular exchange coupling in MAG. The ferromagnetic alloy in the LCL has significantly greater intergranular exchange coupling than the ferromagnetic alloy in MAG, which typically will include segregants such as oxides. The LCL is preferably free of oxides or other segregants, which would tend to reduce intergranular exchange coupling in the LCL. Because the LCL grain boundaries overlay the boundaries of the generally segregated and decoupled grains of MAG, and the LCL and MAG grains are strongly coupled perpendicularly, the LCL introduces an effective intergranular exchange coupling in the MAG

20080112080, May 15, 2008

Nov 13, 2006

11/598419

Byron Hassberg Lengsfield - Gilroy CA, US
Ian Robson McFadyen - San Jose CA, US
James L. Nix - Mogan Hill CA, US
James Terrence Olson - Santa Cruz CA, US
Petrus Antonius Van Der Heijden - San Jose CA, US
Bruce Wilson - San Jose CA, US

G11B 5/127

36012504

A write head for perpendicular magnetic recording having a write pole and first and second return poles. The write head can include a first magnetomotive force source for delivering a magnetomotive force to the first return pole and the write pole and a second magnetomotive force source for delivering magnetomotive force to the second return pole and the write pole. The first and second magnetomotive force sources can be operated independently of one another so that different relative amounts of magnetomotive force can be applied to the first and second return poles. A trailing magnetic shield can be connected with one of the return poles, such as the second return poles, and the variation in magnetomotive force can be used to increase the amount of flux flowing through the trailing shield when increased field gradient is desired (such as when writing a transition), and to decrease the amount of flux through the trailing shield when decreased field gradient and increased write field are desired (such as when writing a long magnetic section on a magnetic medium).