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Textured Yoke Inductive Recording Head

IP.com Disclosure Number: IPCOM000121408D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 52K

Publishing Venue

IBM

Related People

Beaulieu, TJ: AUTHOR [+2]

Abstract

As recorded trackwidths are reduced for thin-film inductive recording heads, the problem of domain noise or domain instability becomes more severe. Typically, this effect is minimized by depositing the films in a magnetic field which is oriented 'across the track.' Another common practice is to carefully choose the film composition such that the combination of the film magnetostriction and the total stress within the films give rise to an additional easy-axis anisotropy directed across-the-track. This resultant anisotropy energetically favors domains whose magnetization lies across the track. Closure domains, which still exist at the track edges, can be reduced at the expense of reduced signal sensitivity by increases in the hard-axis anisotropy of the film(s).

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Textured Yoke Inductive Recording Head

      As recorded trackwidths are reduced for thin-film inductive
recording heads, the problem of domain noise or domain instability
becomes more severe.  Typically, this effect is minimized by
depositing the films in a magnetic field which is oriented 'across
the track.'  Another common practice is to carefully choose the film
composition such that the combination of the film magnetostriction
and the total stress within the films give rise to an additional
easy-axis anisotropy directed across-the-track.  This resultant
anisotropy energetically favors domains whose magnetization lies
across the track.  Closure domains, which still exist at the track
edges, can be reduced at the expense of reduced signal sensitivity by
increases in the hard-axis anisotropy of the film(s).

      This disclosure teaches the use of a mechanical texture or
grooving of the surface of one or more of the films making up a
thin-film head structure.  The pitch of the texture grooves is less
than the typical domain size in the ungrooved structure, and the
depth of the grooves should typically not exceed 10 to 20 percent of
the film thickness. Such a structure gives rise to strong
demagnetization fields wherever the film magnetization is rotated
non-parallel to the axis of the grooves in the films.  Such texturing
or grooving can be accomplished by a variety of means, most easily by
lithographic definition and subsequent sputter etching or ion
milli...