Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Western Digital Technologies, Inc.

Petrus Antonius VanDerHeijden

Barry C Stipe

Hal Jervis Rosen

Neil Smith

Timothy Carl Strand

James Terrence Olson

Jia-Yang Juang

Quang Le

Jeffrey Scott Lille

Neil Leslie Robertson

Henry Hung Yang

Fu-Ying Huang

Eric Edward Fullerton

Alexander Goncharov

Muhammad Asif Bashir

Olav Hellwig

Yoshihiro Ikeda

James Lamar Nix

Byron Hassberg Lengsfield, Iii

A thermally-assisted recording (TAR) disk drive uses 'shingled' recording and a rectangular waveguide as a 'wide-area' heat source. The waveguide generates a generally elliptically-shaped optical spot that heats an area of the recording layer extending across multiple data tracks. The waveguide core has an aspect ratio (cross-track width to along-the track thickness) that achieves the desired size of the heated area while locating the peak optical intensity close to the trailing edge of the write pole tip where writing occurs. The large cross-track width of the waveguide core increases the volume of recording layer heated by the optical spot, which reduces the rate of cooling. This moves the peak temperature point of the heated area closer to the write pole tip and reduces the temperature drop between the peak temperature and the temperature at the trailing edge of the write pole tip where writing occurs.

Magnetic recording disk drive with shingled writing and rectangular optical waveguide for wide-area thermal assistance

A thermally-assisted recording (TAR) disk drive that uses 'shingled' recording and a rectangular waveguide as a 'wide-area' heat source includes a controller that counts the number of writes to each annular band of data tracks. The wide-area heater generates a heat spot that extends across multiple tracks, so that each time an annular band is written, the data in tracks in adjacent bands are also heated. Because the bands are written independently, the number of passes of the heat spot and thereby the number of times the data tracks in a band are exposed to elevated temperatures without being re-written is related to the number of re-writes of the adjacent bands. The number of writes to each band is counted and when that count reaches a predetermined threshold value, one or more tracks in an adjacent band are re-written to avoid reaching an unacceptable level of magnetization decay in the tracks of the adjacent band.

Shingled-writing thermal assistance recording (TAR) disk drive with avoidance of adjacent track erasure from a wide-area heater

A thermally-assisted recording (TAR) disk drive uses a 'wide-area' heater with 'shingled' recording. In shingled recording, the write head pole tip is wider than the read head in the cross-track direction and writes magnetic transitions by making a plurality of consecutive circular paths that partially overlap. The non-overlapped portions of adjacent paths form the data tracks, which are thus narrower than the width of the write pole tip. The data tracks are grouped into annular bands and when data is to be rewritten, all of the data tracks in an annular band are also rewritten. The wide-area heater may be a waveguide with an output end that generates a heated area on the disk recording layer which is wider than the cross-track width of the write pole tip. It has been determined that the use of a wide-area heater with shingled recording does not result in any significant adjacent track erasure (ATE).

Magnetic recording disk drive with shingled writing and wide-area thermal assistance

A microwave-assisted magnetic recording (MAMR) write head and system has a spin-torque oscillator (STO) located between the write pole of the write head and a trailing shield that alters the write field from the write pole. The STO is a stack of layers whose planes lie generally parallel to the X-Y plane of an X-Y-Z coordinate system, the stack including a ferromagnetic polarizer layer, a free ferromagnetic layer, and a nonmagnetic electrically conductive spacer between the polarizer layer and the free layer. In the presence of the write field from the write pole the polarizer layer has its magnetization oriented at an angle between 20 and 80 degrees, preferably between 30 and 70 degrees, with the Z-axis. In the presence of a direct electrical current through the STO stack, the free layer magnetization rotates or precesses about the Z-axis with a non-zero angle to the Z-axis.

Perpendicular magnetic recording write head and system with improved spin torque oscillator for microwave-assisted magnetic recording

A patterned perpendicular magnetic recording medium of the type that has spaced-apart pillars with magnetic material on their ends and with nonmagnetic trenches between the pillars is made with a method that allows use of a pre-etched substrate. The substrate has a generally planar surface at the trenches and comprises material that when heated will diffuse into the magnetic recording layer material and chemically react with one or more of the elements typically used in the recording layer. The pillars are formed of material that will not diffuse into the recording layer. After the recording layer is formed over the entire substrate so as to cover both the pillar ends and the trenches, the substrate is annealed. This results in the destruction or at least substantial reduction of any ferromagnetism in the recording layer material in the trenches so that the trenches are nonmagnetic. The annealing does not affect the recording layer on the ends of the pillars because the pillars are formed of material that will not diffuse into the recording layer.

Perpendicular magnetic recording system with patterned medium and manufacturing process for the medium

A perpendicular magnetic recording write head has a flux conductor in contact with the write pole. The flux conductor is substantially wider than the write pole tip in the cross-track direction and has a blunt end that is recessed from the pole tip end. The region of the flux conductor where its blunt end is in contact with the pole tip is the 'choke' point for the write pole, i.e., the point where the flux density is highest. The flux conductor enables the write pole to be made with no flare, or with a flare angle and throat height with a much wider tolerance, which substantially simplifies the manufacturing process. The write head may have a trailing shield and side shields that substantially surround the write pole tip and remove stray fields that may be produced by the flux conductor, so that regions of the recording layer other than the track being written are not adversely affected.

Perpendicular magnetic recording write head with flux-conductor contacting write pole

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.

Perpendicular magnetic recording system with medium having thin soft underlayer and recording head having thick-throat trailing shield

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San Jose, CA, United States of America

Petrus Antonius VanDerHeijden