Microstructure and micromagnetics of future thin-film media

Compositional microstructures of CoCrTa longitudinal and perpendicular media are studied using analytical transmission electron microscopy. A crystalline 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 grain whose composition is deviated from the average film composition should be taken into account to discuss the magnetic properties including the thermal stability of recorded information. The discussion on KuV/kT values determined using single crystal magnetic thin films, indicates that it is not easy to extend the usable linear density beyond 400 kFCI with a Co-alloy longitudinal recording layer. Employment of perpendicular magnetization will enable us to continuously increase the linear recording density with the conventional Co-alloy recording layer materials. (C) 1999 Elsevier Science B.V. All rights reserved.