Influence of Sputtering Ar Pressure on Characteristics of Tb-Co Amorphous Thain Films

Amorphous Tb-Co films were prepared by diode RF sputtering under various Ar gas pressures and without applying a bias voltage, which is known to induce a large perpendicular magnetic anisotropy. The coercive force, saturation magnetization, and perpendicular anisotropy energy were measured as functions of the Ar pressure, and it was found that at higher pressures a perpendicular magnetic anisotropy was induced. Measurements of the film density and oxygen-content indicated that a large perpendicular magnetic anisotropy is induced for high oxygen contents and low atomic packing densities.