International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hgst Netherlands, B.v.

Michael Paul Salo

Roger William Wood

Albert John Wallash

Zhen Jin

Vladimir Nikitin

Mark Anthony Church

Xiaodong Che

Hardayal Singh Gill

Hendrik F Hamann

Mohamad Towfik Krounbi

Richard Hsiao

Hemantha Kumar Wickramasinghe

Karl Arnold Belser

Weldon Mark Hanson

Howard Gordon Zolla

Glen A Garfunkel

Klaas Berend Klaassen

Chie Ching Poon

Alexander M Taratorin

Edward Hinpong Lee

James Terrence Olson

John David Westwood

Samuel Wonder Yuan

Michael Alex

Joseph Francis Smyth

Wayne Leung Cheung

Samuel Weisan Yuan

Annayya P Deshpande

Alain M Desouches

Samuel Wei-san Yuan

Robert Langland Smith

Ju-Hi John Hong

Timothy J Moran

Scott Arthur Thomas

Muhammad Inayet Ullah

Donald E Horne

James William Reiner

Yongho Ju

Mike Yu Chang

George S Pal

Virat Vasav Mehta

Mark Allen Burleson

Edward Hing Pong Lee

Dave Anthony Freitas

A heat-assisted magnetic recording (HAMR) disk drive has a disk with at least two independent data layers (RLand RL), each data layer storing an independent data stream. At a high laser power both RLand RLare heated to above their respective Curie temperatures and a first data stream is recorded in both RLand RL. At a lower laser power only upper RLis heated to above its Curie temperature and a second data stream is recorded only in RL. The data layers are separated by a nonmagnetic spacer layer (SL) that prevents lower RLfrom being heated to above its Curie temperature at low laser power. The first and second data streams are typically asynchronous. Recorded data is read back from both data streams simultaneously as a composite readback signal. A joint Viterbi detector detects the asynchronous data streams simultaneously from the composite readback signal.

Heat-assisted magnetic recording (HAMR) disk drive with disk having multiple continuous magnetic recording layers

A method of testing a one or more components of a data storage system introduces a first plurality of micro-transitions into a first data write pattern, which is then written to a magnetic media. A read-back signal is generated, and a frequency response of the read-back signal is analyzed to determine performance of the one or more components of the data storage system.

System and method for testing data storage systems utilizing micro-transitions

A method for characterizing a magnetic-recording system for the presence of adjacent-track interference and far-track interference. The method includes writing a plurality of repeating pulse-waveforms on a data track of a magnetic-recording disk at a write element of a magnetic-recording head. The method further includes reading a plurality of read-back signals from the magnetic-recording disk over a band of pseudo-data tracks offset from the data track by corresponding pseudo-data-track offsets in a radial direction of the magnetic-recording disk at a read element of the magnetic-recording head. In addition, the method includes displaying a magnetic-recording-signature map synthesized from the read-back signals from the magnetic-recording disk.

Method for characterizing a magnetic-recording system for the presence of adjacent-track interference and far-track interference

A hard disk drive (HDD) including a magnetic disk, the magnetic disk including a data track. The HDD also includes a synchronized rewrite controller for synchronizing a plurality of rewrites of a data pattern on a location of the track of the magnetic disk and the HDD includes a write head controlled by the synchronized rewrite controller for writing the data pattern on the location of the data track and rewriting the data pattern a plurality of times on the location in synchronization with a prior writing of the data pattern on the data track.

Synchronized rewriting of data

A hard-disk drive (HDD) with a current adjustment component is provided. The current adjustment component changes an amount of current to a magnetic-recording head of the HDD to cause a change in the strength of a magnetic write field produced by the magnetic-recording head in response to a determination that a present position of the magnetic-head head is not in a desired position. To illustrate, in response to a determination that the present position of the magnetic-recording head is further away from an edge of a current track being written than a desired position of the magnetic-recording head, the current adjustment component increases the current to the magnetic-recording head to cause an increase in the strength of the magnetic write field. The change in the strength of the magnetic write field causes data, written by the magnetic-recording head, to be located at a desired location on the magnetic-recording disk.

Correcting errors in position of an HDD write-head

Disclosed is a system and a method for reducing high frequency interference pickup by the read element of the magneto-recording head. The reduction is achieved by reducing the parisitic capacitance between certain elements of the magnetic head. In one embodiment, the areas of the pads and leads, including the areas of the leads over the S1 and the areas of the sensor leads, are reduced. A second implementation involves increasing the separation between the pads and leads and the substrate material. Copper studs or vias may be used to connect the contact pads and the underlying layers. A third implementation includes using a low dielectric constant material as a spacer layer between conductors (leads, pads, magnetic shields) and the substrate.

Reduction of interference pickup in heads for magnetic recording by minimizing parasitic capacitance

A magnetic recording disk drive has a magnetic recording head that includes first and second separating layers, and a heater formed between the first and second separating layers. The heater has a dimension such a thermal protrusion is induced in the recording head and a thermal conductance between the recording head and a recording medium is enhanced.

Magnetic recording head with heating device

A magnetic head system, and method for manufacturing a magnetic head are provided. Included is at least one layer and a heating element positioned adjacent the at least one layer. The at least one layer includes a plurality of sub-layers for providing an optimal thermal barrier.

Thermally assisted magnetic write head system utilizing multilayer thermal barrier coatings

A magnetic transducer including an electrically conductive shield (ECS) which is disposed between the substrate and first magnetic shield is described. The ECS is preferably embedded in an insulating undercoat layer. The ECS is preferably electrically isolated from the magnetic sensor element and is externally connected to a ground available in the disk drive through the arm electronics. Two alternative ways for connecting the ECS to a ground are described. In one embodiment which is only effective with single-ended input type arm electronics, the ECS is connected to a ground through a via to a lead pad for the read head which is connected to the ground of the arm electronics. In a second and more preferred embodiment a separate lead pad is included on the head to allow the ECS to be connected to electronic or case ground when the head is installed in the arm. The extent of the ECS should be sufficiently large to cover the read head portion of the transducer, i.e., from the edge of the first magnetic shield to the outer edges of the read contact pads, but should preferably not cover the write head pads.

Magnetic transducer with electrically conductive shield for reducing electromagnetic interference

A method, devices, and an article of manufacture for reducing magnetic instability in a magnetoresistive read head of a combined read-write head after writing data onto a magnetic storage medium. The last write pulse polarity that results in the least amount of magnetic instability in the read head is determined, and is referred to as the designated polarity. Then, after a set of write pulses is written, it is determined whether the last write pulse has the designated polarity. If the last write pulse does not have the designated polarity, then an additional write pulse with the designated polarity is written. Thus, the last write pulse before a read always has the designated polarity, thereby reducing the magnetic instability of the read head, and consequently improving read head performance.

Unipolar last write which improves magnetic stability

A magneto-resistive (M-R) head has a read element with a servo sensing width as wide as a data track width and a data sensing width of less than one data track width. The two read sensing widths are achieved by using a single read element having a center electrical contact from the M-R read element that effectively reduces the sensing width of the read element. In a first embodiment, the servo sensing width comprises a first portion of the read element and the data sensing width comprises a second, smaller portion of the read element. In a second embodiment, the servo sensing width comprises the entire read element width and the data sensing width comprises a portion thereof. In yet another embodiment, abutting read elements are constructed to enable separate optimization of each sensing width. The wide servo sensing width permits use of a wide servo pattern having servo bursts as wide as a data track width. A position error sensing (PES) signal produced with the wide servo read element and wide servo pattern has increased linearity and accuracy.

Disk drive with wide servo burst pattern and wide servo sensing element

Drive electronics employing unipolar last write for improved magnetic stability

Unipolar last write for improved magnetic stability

A high moment bilayer first pole piece layer of a write head has high magnetic stability for promoting read signal symmetry of a read sensor of a read head. The bilayer first pole piece layer has a first layer of nickel iron and a second layer of iron nitride. The iron nitride has a high magnetic moment for conducting more flux per volume than the nickel iron first layer. In a first aspect of the invention, the nickel iron first layer is highly stabilized by providing it with a negative magnetostriction so that a stress induced anisotropy (H.sub.K) supports an intrinsic uniaxial anisotropy (H.sub.K) of the nickel iron first layer. The iron nitride second layer is formed directly on the nickel iron first layer so that by magnetic coupling the iron nitride second layer has significantly improved magnetic stability. In a second aspect of the invention the iron nitride second layer is provided with a positive magnetostriction which still further increases the magnetic stability of the bilayer first pole piece layer. In a preferred embodiment a net magnetostriction is zero or near zero. Each aspect of the invention improves the asymmetry sigma of the read head.

High moment bilayer first pole piece layer of a write head with high

A method for assessing write element performance in a combined magnetic head that also includes a magneto-resistive (MR) read element for a data storage drive includes exciting the write element with a square wave immediately after lapping the head during manufacture, before mounting the head for operation in the drive. The write element generates an output signal, and the output signal is detected by the read element and then used to determine whether the write element is defective. By using a square wave, temperature gradients in the head and inductive pick up is avoided, thereby facilitating the use of the read element as a test sensor.

System and method for testing a write head in a combined magnetic head

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San Jose, CA, United States of America

Michael Paul Salo