Simulations of torque measurements and noise in thin film magnetic recording media

Numerical simulation of micromagnetic processes in thin-film recording media has been utilized to study the relation between high field torque and transition noise. It has been shown that high field torque depends only on the distribution of grain anisotropy axes and not on the local magnetostatic and exchange interactions. In contrast, the medium noise depends critically on local interactions, in particular the intergranular exchange interaction. Thus, for the range of orientations in this study and by inference all orientations, there is no direct relation between noise and high field torque. It is concluded that other phenomena are likely occurring when magnetic thin films are produced with varying out-of-plane anisotropy orientation, and the transition noise appears to be correlated with high field torque measurements