Abstract
Ferromagnetic resonance (FMR) in particulate media for perpendicular recording has been studied by considering the shape anisotropy of the platelets and the volumetric packing factor. By the obtained FMR equation, the aspect ratio of 3.5 was derived from the angular dependence of the resonance fields in 34 GHz FMR measurements. The ratio is consistent with the value obtained by transmission electron microscopy.