INPLANE ANISOTROPY IN THIN-FILM MEDIA - PHYSICAL ORIGINS OF ORIENTATION RATIO

Variations of in-plane magnetic properties are observed in most commer cial thin-film media. Magnetic anisotropies of varied origins give ris e to preferred orientations quantified by the term orientation ratio ( OR). Several mechanisms for in-plane anisotropy have been proposed. Ob lique angle of incidence effects from vacuum deposition can lead to th e formation of tilted columnar or curved grains resulting in a strong shape anisotropy. The most effort has been involved in understanding ' scratch' anisotropy in textured media where OR develops along texture lines, Mechanisms involving stress, preferred orientation, circumferen tial alignment of grain c-axes, and radial out of plane c-axis effects have been proposed, Recent experiments and calculations suggest that isotropic media, (OR = 1), are superior in signal to media noise, S/N- m, at high recording densities, It is thus important to understand the origin of in-plane anisotropies in thin-film media so as to control t hem for possible recording property improvements or eliminate them alt ogether to achieve an isotropic media.