Low-frequency measurement of anisotropy field

A number of different methods of measuring the anisotropy field H
K
of magnetic films were investigated for application to the automation of low-frequency measurements. These methods included torque, the large signal susceptibility method recommended by the IEEE,[5] the small signal susceptibility, and a new method using the second harmonic component of the magnetization signal. The agreement between the IEEE method and the second harmonic method was found to be good. Both these methods also gave good agreement with values obtained for torque measurements.