Magnetic Properties and Film Structure in Sputtered Amorphous TbCo Films

Dependence of magnetic properties on sputtering conditions is studied in amorphous TbCo films. Perpendicular magnetic anisotropy constant Ku depends strongly on Ar pressure and negative substrate bias voltage VB. When deposited at 10 mTorr Ar pressure without VB or with applying VB of-100 V, the film has positive Ku of 106 erg/cm3 and the hysteresis loop measured perpendicular to the film plane is quite rectangular. Changes in film composition, film structure, and internal stress are investigated also for Ar pressure and substrate bias. The large perpendicular magnetic anisotropy is associated with an ordered fiber structure which comes from moderate bombardment of energetic species.