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Data Recording at Ultra High Density

IP.com Disclosure Number: IPCOM000117947D
Original Publication Date: 1996-Jul-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Gill, HS: AUTHOR

Abstract

Conventional longitudinal magnetic recording is expected to run up to fundamental bit density limitation somewhere between 10 to 100 Gbit/sq. inch. This is basically due to the fact that the written bits become unstable at high bit density. One solution is to use very high coercivity media, the calculations suggest that the thin film disk with coercivity well above 5000 Oe may be required to achieve stable written bits. The main problem then becomes writing on this high coercivity media. Inductive write head pole tip material with saturation magnetization above 30 KG is required for writing on media coercivity above 5000 Oe. Soft magnetic material with saturation magnetization above 30 KG does not exist.

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Data Recording at Ultra High Density

      Conventional longitudinal magnetic recording is expected to run
up to fundamental bit density limitation somewhere between 10 to 100
Gbit/sq.  inch.  This is basically due to the fact that the written
bits become unstable at high bit density.  One solution is to use
very high coercivity media, the calculations suggest that the thin
film disk with coercivity well above 5000 Oe may be required to
achieve stable written bits.  The main problem then becomes writing
on this high coercivity media.  Inductive write head pole tip
material with saturation magnetization above 30 KG is required for
writing on media coercivity above 5000 Oe.  Soft magnetic material
with saturation magnetization above 30 KG does not exist.

      One possible approach is to do thermally assisted magnetic
recording.  The disk material is locally heated with a laser diode
mounted on the slider.  This lowers coercivity locally to accomplish
magnetic recording.  Conventional longitudinal magnetic recording
media, Co-based alloys, perpendicular recording media or ammorphous

TbCo-based alloys are possible examples of thin film disk recording
materials for this application.  Giant magnetoresistive read back
head can be combined with THERMALLY ASSISTED writing to accomplish
integrated read/write head for magnetic recording near the upper end
of above mentioned bit density.