Bias Voltage Dependence of the Magneto-Optical Effects of Rare Earth-Iron Amorphous Films

It was found that GdTbFe films produced with a bias voltage (Vb) of ¿40 V had a very large Kerr rotation angle (¿K). For Vb = ¿60 V, ¿K became extremely small and increased smoothly for Vb ¿ ¿70 V. The reflectivity (R) reached a maximum at ¿30 V and decreased beyond that point. This Vb dependence was much stronger in TbFeCo films than GdTbFe films. R spectra indicated that the electron structure of GdTbFe films was unaffected by Vb. In GdTbCo films, the columnar structure became finer as Vb increased. It was concluded that changes in R result from changes in the ratios of high-density and low-density sections of the columnar structure.