Rotational magnetizations of particulate and thin film recording media

Magnetizations (M_x, along the direction of applied field) as functions of rotational angle (θ) for particulate and thin film recording media in various applied fields (H) were studied. M _k(θ) was analyzed through the Fourier components (C _n) and the corresponding phases (θ_n). The θ_n(H) curves for the increasing- and decreasing-field processes of the particulate recording medium are observed to be separated for H lower than specific values. However, this feature is not evident for the thin film recording medium. The distinction is related with the different microstructures of these two types of recording medium