Magnetic anisotropy field dispersion characterization of advanced perpendicular and longitudinal media

Previous models regarding the field sweep rate dependence of coercivity for granular type recording media are extended to an arbitrary distribution of easy axis orientation and field variation law. The values of H-K and KV/(k(B)T) obtained using the proposed model are in agreement with those obtained from the time dependence of coercivity and DC demagnetization coercivity. For high-density recording media, the shift of the anisotropy field distribution measured by switching methods to lower values with respect to that measured by stiff methods is shown to be the effect of thermal relaxation. Particle interactions are acting only on the width of the anisotropy field distribution measured using different methods, without affecting the position of its maximum.