Comparison between different methods for evaluating the anisotropy field distribution in recording systems

The determination of the anisotropy field distribution P(H/sub /spl alpha//) is made by the second derivative of the magnetization measured perpendicularly to the easy magnetization direction, in the range from saturation to remanence, for a number of magnetic in the same systems. The transverse susceptibility /spl chi/(H) is measured in the same systems. For the systems where the particles are "perfectly" aligned the peak of P(H/sub /spl alpha//) is located at the same field of the peak of /spl chi/(H). In the systems where an appreciable fraction of particles are misaligned the peak of P(H/sub /spl alpha//) is shifted to lower fields while that of /spl chi/(H) does not change its position. The coincidence of the two peaks is assumed as a criterion for the validity of the P(Ha) distribution.