Characterization of Magnetization Reversal Mechanism for Magnetic Recording Media by Rotational Hysteresis Loss Analysis

Abstract

Experimental characterization of magnetic anisotropy and intergranular magnetic coupling for currently developed recording media was carried out with magnetic torque analysis. In thin film media, the magnitude of the magnetic fieled where rotational hysteresis loss vanishes showes an almost constant value in each meterial independent of coercive force Hc. It is concluded that this field nearly corresponds to magentic anisotropy field of grains. Experimental results shows that the increase of Hc in almost all thin film media is mainly caused by the decrease of the strength of intergranular exchange coupling. On the other hand, with decreasing the strength of intergranular coupling, the number of grains where Hc is determined by reversible rotation of magnetization gradually increases. Futhermore, the existence of incoherent magnetization reversal in grains is suggested in the real films especially in CoCrTa media.