Ultra-thin intermediate template layer for perpendicular recording media

An intermediate layer for double-layer perpendicular media was investigated to weaken the intergranular exchange coupling of the CoCrPt alloy recording layer and to reduce the medium noise. When the intermediate layer was composed of an ultrathin Ta layer formed on an MgO film, the coercivity, thermal decay characteristics, and signal-to-noise ratio improved. The required average thickness of Ta layer was within 0.1 to 0.3 nm. The result suggests that the ultrathin Ta layer has an isolated island shape and plays the role of a template for the magnetically isolated grain growth of the recording layer.