Effects of nitrogen, oxygen and air on the magnetic properties of sputtered CoCrTa thin film recording discs

The effects of partial pressures of oxygen, nitrogen and air on sputtered CoCrTa ternary alloys have been studied relative to their microstructure and magnetic properties. The results show that oxygen affects the crystallinity and orientation of Co ternary alloys more severely than nitrogen or air. The effect of air was intermediate between that of O₂ and N₂. Introduction of oxygen results in a very large reduction in coercive force of the films. The coercivity reduction due to nitrogen is moderate, and the effect of air is intermediate between the effects of O₂ and N₂. However, no significant change in saturation magnetization values are observed due to the introduction of impurity gases