Distribution of anisotropy field in recording media deduced from the hysteresis curve

The distribution of anisotropy fields in magnetic recording media is carried out by performing the second derivative of the magnetization curve detected in perpendicular direction with respect to the easy axis of the system, following a procedure similar to that used for the soft magnetic materials. The method is applied to the CoCr films with the anisotropy direction perpendicular to the film plane. It was found that the field at the peak of the distribution function agrees with the anisotropy field measured by the torque method. For particulate media,the shape of the anisotropy distribution function depends both on the particle orientation ratio and on the interparticle interactions; as a consequence, the anisotropy distribution function determined on these materials does not represent the intrinsic anisotropy field distribution of the particles but the anisotropy distribution as it appears in that particular specimen. In any case, this function is useful for understanding the magnetic behavior of the system. (C) 1997 American Institute of Physics.