Comparison of the effects of oxygen on cobalt and cobalt-chromium thin films

Oxygen has been intentionally incorported into sputtered Co and Co-Cr films by the addition of controlled amounts of oxygen to the argon sputter gas atmosphere. The influence of the oxygen incorporation was evaluated by the analysis of the magnetic properties and the structural characteristics of the films. The coercivity was found to increase with increasing oxygen incorporation for both Co and Co-Cr films. The saturation magnetization (Ms) in Co decreases as the oxygen content increases whereas Msfor Co-Cr films initially increases as Cr is depleted by selective oxidation. The mechanism for the change in coercivity is attributed to changes in the coupling between magnetic regions, rather than changes in grain size.