Digital recording performance of Ba-ferrite media

Abstract

Barium ferrite media have created a lot of interest for digital and analog applications because of their potential to achieve high recording densities. To fully exploit this potential, it is necessary to develop media with good perpendicular orientation and to employ high saturation narrow gap heads. It is possible, however, to obtain very good recording performance utilizing Ba‐ferrite media which are nonoriented or only partially oriented and ordinary ferrite heads for high‐density digital recording applications. In this study, we investigated the performance of such media in rigid disk form using conventional and narrower gap ferrite heads, and obtained much better short wavelength response than that obtained from high‐coercivity cobalt‐modified iron oxide media. The overwrite modulation of these media, however, is only marginally acceptable. The modulation noise observed is much larger for longitudinally oriented than for perpendicularly oriented media. A simple model is proposed to explain the origin of this noise and its dependence on the direction of orientation.