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Memory Plane Production

IP.com Disclosure Number: IPCOM000094515D
Original Publication Date: 1965-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Middlehoek, S: AUTHOR

Abstract

The method of producing thin films with uniaxial magnetic anisotropy is used in evaporation processes with or without heated substrates. It reduces deviations of the easy axis, i. e., skew, in the outer parts of the planes. The different thermal expansions of substrate and vapor deposited material causes stresses in the magnetic film. These lead to stress anisotropy and consequently, to concave (left) or convex (right) deviations of the easy axis, depending upon the sign of the magnetostrictive coefficient lambda. For Ni-Fe compositions with more than 81% Ni this coefficient lambda is negative. For those with less than 81% Ni it is positive.

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Memory Plane Production

The method of producing thin films with uniaxial magnetic anisotropy is used in evaporation processes with or without heated substrates. It reduces deviations of the easy axis, i. e., skew, in the outer parts of the planes. The different thermal expansions of substrate and vapor deposited material causes stresses in the magnetic film. These lead to stress anisotropy and consequently, to concave (left) or convex (right) deviations of the easy axis, depending upon the sign of the magnetostrictive coefficient lambda. For Ni-Fe compositions with more than 81% Ni this coefficient lambda is negative. For those with less than 81% Ni it is positive.

Memory planes produced by this method are composed of two magnetic layers evaporated on top of each other. The coefficient lambda of one layer is made positive and that of the other negative by using melting alloys of, e. g., 80/20 and 82/18 Ni-Fe, respectively. Owing to the strong exchange coupling between the two layers, the easy axis deviations occurring in both layers are compensated. Memory planes without skew result.

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