Microstructure and micromagnetics of future thin-film media

Compositional microstructures of CoCrTa longitudinal and perpendicular medi a are studied using analytical transmission electron microscopy. A crystall ine grain model consisting of a Co-rich core grain surrounded by a Cr-rich shell layer is proposed as the minimum magnetic unit of low-noise thin-film recording media. The intrinsic magnetic properties of core crystalline gra in whose composition is deviated from the average film composition should b e taken into account to discuss the magnetic properties including the therm al stability of recorded information. The discussion on KuV/kT values deter mined using single crystal magnetic thin films, indicates that it is not ea sy to extend the usable linear density beyond 400 kFCI with a Co-alloy long itudinal recording layer. Employment of perpendicular magnetization will en able us to continuously increase the linear recording density with the conv entional Co-alloy recording layer materials. (C) 1999 Elsevier Science B.V. All rights reserved.