Bubble domain memory materials

Abstract

The selection and preparation of bubble domain materials is discussed in the light of materials requirements for bubble domain memories. The history of bubble domain materials development is outlined with emphasis on the discovery and exploitation of two types of materials, magnetic garnets and amorphous magnetic alloys. It is shown how the great compositional flexibility of the garnet system has led to many garnet choices for device use without imposing undue hardship on the materials developer and supplier, and how liquid phase epitaxy of garnet films is a simple way of providing reproducibly films that meet device requirements. Amorphous magnetic alloys are discussed with emphasis on Gd-Co-Mo compositions. In the search for small bubble materials, it is pointed out that both garnets and amorphous alloys have limitations. In the former case,qwill usually be too low and in the latter case, the drift of properties with temperature may be unacceptable.