Magneto-optic properties in R.F. sputtered Co-Cr films

The Kerr rotation angle has been measured at λ = 6328Å, for the Co-Cr films (0-29.5at%Cr). The films were deposited by magnetron rf sputtering on glass substrates. Over the range of 18- 29.5at%Cr, the deposited films were found to have perpendicular anisotropy, the Kerr rotation angles in the saturated state were 6-0.3 minutes, and the reflectivities were 63-58%. The Kerr rotation angle of the Co-Cr films was attributed to the magnetic moment of Co. The external field dependence of the Kerr rotation angle had a hysteresis with a large coercive force and remanence, in comparison with those obtained by magnetic measurement, indicating that the coercivity near the film surface is larger than that of inside. The Kerr hysteresis loop can be measured and is useful to estimate the magnetic properties of Co-Cr films. It can be applied not only to the single Co-Cr films but to the double-layer films. The domain pattern of recorded signal on Co-Cr film can be observed by a microscope using the polar Kerr magnetooptic effect.