Degradation mechanism of magnetic properties of Co-O film caused by residual gas

The effects of the residual gas pressure on the magnetic properties of Co-O films were studied. The coercivity (Hc) and squareness ratio (Mr/Ms) decreased with increasing the residual gas pressure. Among the species, water vapor played a decisive role in degrading the magnetic properties. Analysis revealed that the degradation was caused by decrease in the anisotropy field (Hk) and increase in the easy axis angle (/spl alpha/) of the film. These changes in He and /spl alpha/ by water vapor can be explained qualitatively.