Magnetic and magneto-optic properties of amorphous TbFeCo magnetic films

Amorphous TbFeCo films have been studied to obtain a higher Kerr rotation angle. The Kerr rotation of Tb21(Fe100-xCox)79increases with the increase of Co concentration and has a maximum value of 0.52 degree at X=50, 840nm and decreases in X > 50. This Kerr rotation angle of 0. 52 degree is improved by a factor of 2. 5 compared to that of Tb Fe. In amorphous Tb21(Fe100-xCox)79film, the wavelength dependence of Kerr rotation angle were measured from 500nm to 840nm. Kerr roation increases monotonically with the increase of wavelength and no peak was observed in spectra. However, it was found that there was an obvious difference of the increase rate of 8k, from 500nm to 840nm, between the R-Co alloy system and the R-Fe alloy system. The increase of Kerr rotation angle depends on the difference of the contribution of pure Fe and Co to 8k.