Effect of in-plane easy axis orientation in narrow track recording

The effect of crystalline easy axis orientation in longitudinal thin-film recording media is studied via micromagnetic modeling. The focus is on bicrystal films, in which the crystalline easy axes are oriented in two specified orthogonal directions. Hysteresis properties, side writing phenomena, and on-track noise behavior of the films are studied. Comparisons were made with oriented and planar isotropic films. It has been found that in the bicrystal film the effective magnetic easy axes are along the diagonal directions in between the crystalline easy axes in the film plane. Along the effective easy axes, the hysteresis loop is similar to that of the oriented film with high remanent and coercive squarenesses. Unlike oriented films, the side-written band in the bicrystal film acts like an erase band containing no edge transitions. The on-track noise of the bicrystal film is low at all recording densities, while the noise in oriented films sharply increases at high recording densities. It is concluded that the bicrystal film is more suitable for narrow track recording than either the oriented film or the planar isotropic film