Structuring of bubble domains in a bubble domain memory plane

Abstract

Defining the structuring of bubble domains in the magnetizable layer of a bubble domain memory plane is determined by modification of the magnetic characteristics of the magnetizable layer in the confinement area. The memory plane is comprised of a non-magnetic Gadolinium Gallium Garnet (GGG) layer which is a supporting substrate upon which is formed by the liquid phase epitaxy (LPE) method a magnetizable layer in which bubble domains are capable of being generated, sustained and moved about. Formed upon the bubble domain supporting magnetizable layer is a matrix array of conductive drive lines, the intersections of which define respective memory areas. In each memory area the position of the bubble domain in the magnetizable layer is determined by modifying the magnetic characteristics of the magnetizable layer in a confinement area as by an ion milling process. The ion milled confinement area along the line of the thickness gradient generates a perpendicular field H.sub.P that tends to prevent the bubble domain from escaping from the so-defined confinement area. The perpendicular field H.sub.P component that is generated by the thickness gradient produces a sharp potential minimum at the edge of the ion milled region. This potential minimum draws the bubble domain toward the edge of the thickness gradient whereby the bubble domain size may be expanded to fill the confinement area. Additionally, the confinement area may consist of a plurality of interconnected lobes each of which defines a given bubble position, each of which bubble positions may be utilized to define a memory position that may be utilized in an optical page composer of an optical data processing system.