Microstructure of sputtered garnet films for magneto-optical recording media

Abstract

Sputtered garnet films have a high potential for use as a magneto‐optical recording medium. However, the medium noise is thought to be large because of its crystal boundaries. We investigated the microstructure of films on GGG substrate, using TEM and SEM. The film crystallized by postannealing shows a rectangular hysteresis loop with high coercivity, and has an uneven surface. This is because the direction and size of each crystallite is not uniform. However, the film crystallized during deposition has quite a smooth surface, but does not have magnetic properties suitable for use in magneto‐optical recording. This film has a mosaiclike structure, in which all crystallites are uniformly oriented. We found that ion implantation of Ne⁺ and successive annealing of the film crystallized during deposition improved the magnetic properties without roughening the surface.