MEDIA NOISE AND INTERPARTICLE INTERACTIONS OF BARIUM FERRITE PARTICULATE RIGID DISKS

This paper discusses the relationship between media noise characteristics and interparticle interactions for a series of longitudinal barium ferrite rigid disks with a variation in volumetric particle packing densities. The magnetomotive force dependences of reverse dc erase noises are measured and compared with interaction field factors. The magnetomotive force dependence of the reverse dc erase noise changes from dip-type to peak-type and the peak height increases with decreasing interaction field factor value, that is with increasing positive interparticle interactions. The coercivity and switching field distribution values decrease with increasing positive interparticle interactions and the volumetric particle packing density. The magnetic interactions in barium ferrite disks consist of two mechanisms, the interparticle positive interactions in stacks of barium ferrite particles, and the negative interactions between the stacks in which the magnetic moments of the barium ferrite platelet particles are aligned in the stack direction.