High coercivity sputter-deposited maghemite thin-film disk

The fabrication and read-write characteristics of a high-coercivity sputter-deposited maghemite (γ-Fe2O3) thin-film disk medium is discussed. By employing a low sputtering gas pressure, severe internal strain is introduced into the films. This internal strain markedly increases coercivity. Furthermore, the films are composed of fine crystallites (300-400 Å in diameter), which result in extremely low media noise. A high coercivity (1060 Oe) γ- (Fe0.954Co0.02Ti0.02Cu0.015)2O3thin-film disk medium with a thickness of 0.095 μm exhibited superior read-write characteristics (e.g., a 2493 FRPM recording density D50and a 42 dB signal-to-noise ratio). These results show that sputter-deposited maghemite films have a promising potential for use as high-density disk media.