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Simple Test Structure for Determining Thin Film Head Properties

IP.com Disclosure Number: IPCOM000106039D
Original Publication Date: 1993-Sep-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Jahnes, CV: AUTHOR [+4]

Abstract

Disclosed is a simple test structure which allows the performance of magnetic materials that would be used in thin-film recording heads to be tested without the complication of building complete heads. By measuring the permeability of the material after it is patterned into this shape, accurate predictions of complete thin-film head performance can be made. Material and topological effects can be measured.

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Simple Test Structure for Determining Thin Film Head Properties

      Disclosed is a simple test structure which allows the
performance of magnetic materials that would be used in thin-film
recording heads to be tested without the complication of building
complete heads.  By measuring the permeability of the material after
it is patterned into this shape, accurate predictions of complete
thin-film head performance can be made.  Material and topological
effects can be measured.

      One method to test thin film materials and structures is to
measure the permeability of the material as a function of frequency
and field strength.  See [*]  for a method to measure permeability as
a function of sample width.  This is done by patterning a film into
an array of stripes of a given width, and then measuring the
permeability of the array.  This technique predicts that 2 mum thick
permalloy patterned into 5 mum wide stripes would have very low
permeability.  Since thin-film heads can be made to function with 5
mum track widths, this is not an adequate structure to be used as a
predictive test.

      The yoke of a thin film head, which is 5 to 50 times wider that
the pole tips of the head, can be thought of as stabilizing the
domain structure of the device, and hence improving its performance.
Fig. 1 shows the proposed test structure, which more closely mimics
the performance of a thin film head.  The test pattern is a series of
heads that are "unfolded" and then...