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Superconducting Underlayer for Longitudinal Recording Media

IP.com Disclosure Number: IPCOM000121409D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Beaulieu, TJ: AUTHOR [+2]

Abstract

Conventional longitudinal magnetic recording eventually becomes limited by the width of the recorded transitions, once the flying height becomes vanishingly small and the gap dimension is correspondingly small. The transition width can be reduced by increasing the coercivity of the media, but an upper limit on coercivity is determined by the ability of the write head to switch the media.

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Superconducting Underlayer for Longitudinal Recording Media

      Conventional longitudinal magnetic recording eventually becomes
limited by the width of the recorded transitions, once the flying
height becomes vanishingly small and the gap dimension is
correspondingly small.  The transition width can be reduced by
increasing the coercivity of the media, but an upper limit on
coercivity is determined by the ability of the write head to switch
the media.

      By introducing a superconducting layer beneath the thin-film
recording layer, the longitudinal magnetic field from the recording
head can be roughly doubled.  The boundary conditions for the problem
can be satisfied by replacing the superconducting layer with an image
head located below the underlayer-media boundary, at a distance equal
to the distance of the actual head from this boundary. The 'sign' of
this image head is positive, meaning that the vertical fields cancel
near the boundary, while the longitudinal field is doubled.

      With the advent of high temperature superconductors, and the
ever-increasing transition temperatures, it becomes more likely than
before that practical devices employing these materials will become a
reality.  It is the purpose of this disclosure to teach the use of a
superconducting underlayer with a HIGH coercivity thin-film media.
For a given flying height, gap dimension, and magnetomotive force,
the superconducting underlayer allows writing a coercivity of up to
TWI...