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Browse Prior Art Database

Spinel Ferrites for Bubble Domain Device Applications

IP.com Disclosure Number: IPCOM000080952D
Original Publication Date: 1974-Mar-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Agajanian, AH: AUTHOR

Abstract

Spinel ferrite compositions of the formula MgFe(2-x)Al(x)O(4) where x indicates the amount of Al substituted for Fe in MgFe(2)0(4), have the properties of a low-saturation magnetization, a large negative magneostriction constant, and a lattice constant compatible with a nonmagnetic substrate for epitaxy. The properties make the compositions useful in magnetic bubble domain memory applications.

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Spinel Ferrites for Bubble Domain Device Applications

Spinel ferrite compositions of the formula

MgFe(2-x)Al(x)O(4) where x indicates the amount of Al substituted for Fe in MgFe(2)0(4), have the properties of a low-saturation magnetization, a large negative magneostriction constant, and a lattice constant compatible with a nonmagnetic substrate for epitaxy.

The properties make the compositions useful in magnetic bubble domain memory applications.

In a standard notation the general formula for the compositions may be written in the form

(Image Omitted)

where ions in the square brackets occupy B sites, and those to the left of square brackets occupy A sites. a is the degree of inversion of MgFe(2) 0(4) and partly depends on the temperature from which it is quenched during the heat treatment
(1). The variation of the magnetic moment of these ferrites with Al substitution has been studied by Jones and Roberts (2). Substitution of Al(+++) ions for Fe(+++) ions in MgFe(2)O(4) reduces the magnetization to zero, and then magnetization changes direction. The variation of M(s) with Al content is given in a schematic diagram in the figure.

The optimum compositions of this process are given for values of x in the range of 0.2 Less Than or Equal To x Less Than or Equal To 0.8, which corresponds to th values of saturation magnetization in the range of 60 gauss or 4 Pi M(s) Less Than or Equal To 1000 gauss.

Thin film single crystals of these ferrites can be grown by liquid phas...