Study of the origin of orientation ratio in high-density longitudinal magnetic recording media

A study on the origin of orientation ratio (O.R.) in high-density recording media on mechanically textured substrates is reported. C-axis distribution of Co grains in textured case observed using high resolution transmission electron microscopy (HRTEM) images shows its preferred orientation along the circumferential (along the groove) direction. The asymmetrical easy axis distribution is seen by maximum torque observed in different directions along the plane of the film. Diffraction patterns from several individual grains of the Cr under-layer are analyzed and indicated the preference of Cr < 110 > along the circumferential direction. This could be the reason for C-axis of Co grains to show the preferred anisotropy along circumferential direction.