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Significant Improvements In NiFe Film Properties

IP.com Disclosure Number: IPCOM000123492D
Original Publication Date: 1998-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 5 page(s) / 233K

Publishing Venue

IBM

Related People

Pinarbasi, M: AUTHOR [+3]

Abstract

Thin permalloy (Ni 1-x Fe x; x+20%) films are used as field sensors in magnetoresistive magnetic recording read heads. The resistance of the permalloy layer depends upon the orientation of the magnetization of the film with regard to the sense current passing through the layer. Thus when the moment of a thin permalloy layer is rotated by a sense field, such as that emanating from a magnetic bit written on a magnetic thin film medium in a magnetic recording disk drive, the resistance of the layer is changed, thereby allowing sensing of the magnetic bit. The sensitivity of the film to magnetic field changes is a critical property property which determines the signal from an MR head.

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Significant Improvements In NiFe Film Properties

   Thin permalloy (Ni 1-x Fe x; x+20%) films are used as
field sensors in magnetoresistive magnetic recording read heads.  The
resistance of the permalloy layer depends upon the orientation of the
magnetization of the film with regard to the sense current passing
through the layer.  Thus when the moment of a thin permalloy layer is
rotated by a sense field, such as that emanating from a magnetic bit
written on a magnetic thin film medium in a magnetic recording disk
drive, the resistance of the layer is changed, thereby allowing
sensing of the magnetic bit.  The sensitivity of the film to magnetic
field changes is a critical property property which determines the
signal from an MR head.  The larger the change in resistance of the
film with magnetic field, as typically characterized by the
magnetoresistance (dR/R), the greater the signal will be.  High
temperature processing, either by depositing the NiFe films at high
temperatures (200 degrees to 500 degrees Centigrade) or by annealing
the films at high temperatures (250 degrees to 550 degrees
Centigrade) has been shown to improve the dR/R of thin permalloy
films deposited on glass or quartz substrates or on thin films of
A1203 or Si02 deposited on a variety of substrates including silicon
and various ceramics (1,2,3).

   In the present study, the dR/R of thin NiFe films has been
significantly improved by a post-deposition annealing process.  In
one study the films w...