Recommendation of a simple and universally applicable method for measuring the switching field distribution of magneting recording media

The most common methods for assessing the switching field distribution (SFD) of magnetic recording media are compared for samples of acicular magnetic particles made of different types of magnetic materials and having various degrees of particle orientation. It is shown that the method of using the maximum slope
dM/dH = M_{R}/H_{c}(1-S*)
at
M = 0
of the magnetic hysteresis loop
M(H)
can be used to characterize SFD of the irreversible magnetization processes which correlate to the recording performance. Thus, (1-S*) is recommended as the most easily accessible and universally applicable figure of merit for SFD.