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Magnetostriction Mapping of Soft Magnetic Films On Thick Rigid Substrates

IP.com Disclosure Number: IPCOM000119255D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Gudeman, CS: AUTHOR

Abstract

Disclosed is a method that provides accurate mapping of the saturation magnetostriction g in magnetically soft thin films that are deposited on thick rigid substrates. g is determined by measuring the change in the anisotropy field with a known change in the film strain (e). Thus, this method can be more accurately termed a measurement of the magneto- elastic strain coefficient h. A simple relationship, which requires accurate values of only the saturation magnetization Ms, Young's Modulus Y, and Poisson's ratio v of the magnetic film is used to convert from h to g. Knowledge of the film thickness or the elastic properties of the substrate is unnecessary.

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Magnetostriction Mapping of Soft Magnetic Films On Thick Rigid Substrates

      Disclosed is a method that provides accurate mapping of
the saturation magnetostriction g in magnetically soft thin films
that are deposited on thick rigid substrates.  g is determined by
measuring the change in the anisotropy field with a known change in
the film strain (e).  Thus, this method can be more accurately termed
a measurement of the magneto- elastic strain coefficient h.  A simple
relationship, which requires accurate values of only the saturation
magnetization Ms, Young's Modulus Y, and Poisson's ratio v of the
magnetic film is used to convert from h to g.  Knowledge of the film
thickness or the elastic properties of the substrate is unnecessary.

      Except for the addition of the laser beam deflection apparatus,
the Kerr BH Imager used in these measurements is identical to that
described previously [1].  The beam deflection system (see the
figure) consists of a near-normal laser beam that is reflected off of
the film and onto a two-axis Si position sensor.  At each location,
the position of the laser spot at the position sensor is extracted
from the position sensor voltages and converted into angular
deflection, the derivative of which is proportional to the film
curvature.  The film strain en is then expressed in terms of the
position sensor output voltages Vn, the distance from the sample to
the position sensor L, and the thickness of the substrate t as where
the subscript n denotes either the easy axis (EA) or t...