Micromagnetic study of track edge and medium orientation effects in high areal density recording

Abstract

A micromagnetic recording model is used to examine the effects of media-grain anisotropy distributions on the quality of recorded tracks at high areal density. Write head fields derived from the Finite Element Method, which accounts for pole-tip and corner saturation, are applied to a Landau-Lifschitz-Gilbert model of thin-film longitudinal media. The read-back signal from the recorded transitions is determined through a micromagnetic model of a GMR spin-valve device. Medium magnetization profiles, percolation, track-edge effects, and read-back voltages are reported for 10 Gb/in 2 applications. As the anisotropy axes become more oriented along the down-track direction, both the sharpness of the transitions as well as the extent of erase bands improve dramatically. The cases of both saturated and unsaturated writer pole tips are examined. The effect of an out-of-plane component of the medium anisotropy axes is also examined. Even with a moderately wide Gaussian distribution, the effect on transition quality is minimal. Erase bands increase to some extent but the read-back signal is little affected.