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Control of Domain Configurations in Thin Film Heads by Ion Implantation

IP.com Disclosure Number: IPCOM000107298D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Eldridge, JM: AUTHOR [+2]

Abstract

The domain configuration in the yoke of high performance thin film magnetic recording heads can be metastable. The effect of this magnetic instability is to cause noise in the channel which can lead to unacceptable error rates. The origin of the problem is thought to be complex stress patterns produced in the yoke during processing. In contrast to the ideal stress pattern, i.e. one that always forces the magnetization to lie along the track width, processing conditions generate stresses that allow magnetization in the domains to lie along other directions. Variability in process conditions can generate not one, but many different stress patterns.

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Control of Domain Configurations in Thin Film Heads by Ion Implantation

       The domain configuration in the yoke of high performance
thin film magnetic recording heads can be metastable.  The effect of
this magnetic instability is to cause noise in the channel which can
lead to unacceptable error rates.  The origin of the problem is
thought to be complex stress patterns produced in the yoke during
processing.  In contrast to the ideal stress pattern, i.e. one that
always forces the magnetization to lie along the track width,
processing conditions generate stresses that allow magnetization in
the domains to lie along other directions. Variability in process
conditions can generate not one, but many different stress patterns.

      This article teaches a method of inducing stress patterns, of
the proper sign, magnitude, and at the proper position on the yoke,
to eliminate or reduce the magnetic instability.  The object is to
adjust the magnetic anioptropy of the yoke, via the magnetostriction
energy, to achieve a reproducible domain configuration.  The stress
distribution will be induced and controlled by ion implantation.

      During implantation, an altered layer forms on the top of a
film.  The layer has, in general, a different stress state than the
bulk.  The depth of the altered layers and its stress are controlled
by the implantation parameters. The altered layer, in turn, changes
the stress state of the bulk of the film.

      Experiment...