Magnetization reversal for barium ferrite particulate media

Abstract

A perpendicularly oriented Ba ferrite particulate medium was investigated with regard to the magnetization reversal process. Coercivity and remanence coercivity for the medium were found to be decreasing and increasing functions, respectively, of the angle between the easy axis and the applied field. The angular dependence of remanence coercivity, being supported by the rotational hysteresis integral value, implies that the magnetization reversal process for the medium is incoherent. A fanning model for the two aligned particles with uniaxial crystalline anisotropy, was developed. This model yields variable angular dependencies of coercivity for varying ratios of a crystalline anisotropy field (H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</inf> to a dipole-dipole interaction field (H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> ). Taking an appropriate H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</inf> /H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> value, the model can predict the angular dependence of coercivity and remanence coercivity for the medium.