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New Magneto-resistive Stripe Height Design for Wear and Signal To Noise Ratio Improvement

IP.com Disclosure Number: IPCOM000107979D
Original Publication Date: 1992-Apr-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 98K

Publishing Venue

IBM

Related People

Kahwaty, VN: AUTHOR

Abstract

A magneto-resistive (MR) stripe height design concept is shown to compensate for tape wear non-uniformity on multi-track magnetic recording heads using MR sensors. A particular concern is the ability to maintain high Common Mode Rejection Ratio for center-tapped MR sensors to improve system performance with head wear. The problems of low amplitude and MR stability exposure are minimized with this concept.

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New Magneto-resistive Stripe Height Design for Wear and Signal To Noise Ratio Improvement

       A magneto-resistive (MR) stripe height design concept is
shown to compensate for tape wear non-uniformity on multi-track
magnetic recording heads using MR sensors.  A particular concern is
the ability to maintain high Common Mode Rejection Ratio for
center-tapped MR sensors to improve system performance with head
wear.  The problems of low amplitude and MR stability exposure are
minimized with this concept.

      For various magnetic head designs, particularly ferrite heads,
with increased track density using MR sensors it will be necessary to
increase the initial stripe height to accommodate increased wear due
to increased tape passes and to the higher proportion of soft
magnetic isolation material, such as glass, at the air bearing
surface. Conversely, MR stability studies have shown that a minimum
stripe height is desirable to improve amplitude and avoid excessive
MR instability due to reduced MR shape anisotropy. Another fact is
that the edge tracks are shown to wear far faster than internal
tracks on typical multi-track tape magnetic recording heads.  Also,
it is found that edge track wear causes severe loss of Common Mode
Noise Rejection with center-tapped MR read elements.  The Common Mode
Noise Rejection depends on the resistive matching of the sides of the
center-tapped MR element commonly referred to as delta-R and is a
major limit to head life.  For write elements it is found that edge
tracks will develop a higher efficiency than the other elements on
the head due to a comparative reduction in throat height; therefore,
the possibility of optimizing recording through head life is reduced.

      The idea of using a uniquely designed stripe height on the
outer tracks compared to the inner tracks since the wear of the outer
tracks is much higher than the inner tracks is disclosed.  The idea
is to design the stripe heights such that they relate inversely to
the expected wear profile of the head.  For example, on a 36-track
head stripe heights to inversely match t...