Analysis on magnetization transition of CGC perpendicular media

Abstract

Modeling and read/write characteristics of coupled granular/continuous (CGC) perpendicular recording media are described. The media consists of a continuous layer with a strong in-plain exchange coupling and a granular layer with magnetically isolated grain structure. The two layers are coupled by interlayer exchange coupling. Hysteresis loop squareness approaching unity is realized in CGC samples with only a 3-6 nm continuous layer on a CoCrPt granular layer. An approximated energy calculation shows a domain-wall pinning effect and transition smoothing due to interlayer exchange coupling between the two layers. Read/write measurements for the CGC media indicate signal-to-noise ratio improvement in association with transition jitter reduction, which suggests transition smoothing. Thermal stability is improved by interlayer exchange interaction.