Magnetic Properties and Noise Characteristics of FeC Film for Backlayer of Double-layered Perpendicular Magnetic Recording Medium

Abstract

The relationships among magnetic properties, film structures, and noise characteristics of FeC films were examined with particular emphasis on soft magnetic backlayers of double-layered perpendicular magneti recording media. FeC films were fabricated on glass disks using DC magnetron sputtering by a conventional cosputtering method with Fe and C targets. The films were deposited at room temperature without application of magnetic fields. No heat processes were applied after deposition. The Fe and C contents in the films were varied by individually controlling the electrical power for the Fe and C targets. Nana-scale downsizing for both the film structures and the magnetic domains and the formation of radial magnetic anisotropy in an as-deposited state produce soft magnetic FeC films with both low media noise and high saturation magnetization of around 19 kGauss. A coercive force in the magnetic easy axis of less than 1 Oe reduces media noise in the FeC film. An anisotropy field of over 20 Oe suppresses spike noise in the FeC film. A high electrical resistivity of about 120 μΩcm and a high permeability of around 900 that remains constant up to 1 GHz in FeC films suggest future applications for high density recording media.