BETA-TUNGSTEN UNDERLAYER FOR LOW-NOISE THIN-FILM LONGITUDINAL MEDIA

This work investigates the magnetic and media noise properties of Co-15 at. % Cr media having β-W underlayer. These results are correlated with the crystallography and the grain structure of the media. Results show that H c increases with β-W underlayer thickness up to around 100 nm and becomes constant beyond that. The β-W underlayer seems to influence the epitaxial growth of Co (112̄0) and thus has c axis in the plane. Media noise increases with β-W underlayer film thickness. CoCr/β-W media exhibits almost two times lower media noise than a CoCr/Cr media having identical Hc and Brt. The low noise behavior in CoCr/β-W is due to the unique grain structure which reduces the exchange interaction between the CoCr grains.