Correlation of rotational magnetic properties and noise in thin film magnetic recording media

Possible correlations between media noise and the magnetic, torque, and rotational energy losses in thin film media have been investigated. Torque magnetometry was used to measure the rotational hysteresis losses as a function of the applied field, and the rotational hysteresis integral, R_h, was computed. A direct correlation between R_h and modulation noise was found, confirming the hypothesis that this type of noise arises from domain-like reversals. An additional significant by-product of the torque measurements in and out of the plane of the film was the determination of the preferred direction of the easy axes of the crystallites comprising the film. The results are in agreement with measurements of the angular dependence of coercivity out of the plane of the films. Noise characteristics of thin-film media are discussed