Magnetostrictive phenomena in metallic materials and some of their device applications

The phenomenon of magnetostriction, or the change in a body's dimensions during the magnetization process, was first reported by Joule. Since then, the interaction between strain and the magnetization process has been studied extensively, particularly in the magnetic metals and alloys that have been found to be of technological importance. The purpose of this paper is to review magnetostrictive phenomena in metallic materials and to discuss a number of devices making use of magnetostriction. After presenting some fundamentals of magnetostriction, a review is given of magnetoelastic effects and magnetoelastically induced anisotropies in magnetic films. Some of the domain patterns and domain visualization techniques that have been found to be related to the magnetostrictive properties of magnetic materials are discussed. The application of magnetostrictive materials to memory devices is reviewed. Included are such areas as magnetostrictive delay lines, ferroacoustic memories of both the flat film and wire type, thermo-strictive recording, and fiat film displays and display memories.