Effect of soft magnetic underlayer on magnetization microstructure of perpendicular thin film media

Analytical magnetic force microscopy has been applied to investigate the relationship between the soft magnetic underlayer and the microscopic magnetization structures of double layered perpendicular media. The magnetization structures of the CoCrPtTa perpendicular media with Co-Nb-Zr, Co-Ta-Zr, Fe-Ta-C, and Fe-Al-Si soft magnetic underlayers are compared. The medium with Co-Ta-Zr underlayer shows low medium noise and high resolution characteristics at high recording densities. The magnetization irregularities of perpendicular media are strongly affected by the soft magnetic underlayer material.