Magnetic property control by using a composite template for dual-layered perpendicular media

Abstract

Thin composite template layers for dual-layered perpendicular media have been studied. By combining a thin amorphous layer and a thin NiAl seed-layer, thermally stable and low noise media have been realized simultaneously. By changing the thickness ratio of the top amorphous layer and the bottom seed-layer, the magnetic properties of the recording layer can be controlled without changing the magnetic spacing between the soft underlayer and the write pole. Magneto-optical Kerr effect, transmission electron microscopy, and spin-stand measurements were performed to investigate the influence of different composite templates on the recording properties. It will be shown that the composite template allows the optimization of thermal stability and media noise in perpendicular media. The thermal stability of the media was measured by signal decay measurement using a spinstand and dynamic coercivity measurements using the Kerr effect. The KuV/kBT values, as obtained by the latter method, are consistent with the signal decay data. Those results demonstrate that the presented dynamic coercivity measurement is a very useful method for evaluating the thermal stability of dual-layered perpendicular media.