Magnetic and Magneto-Optical Properties of Amorphous TbFeCoBi Thin Films

Bi was added to TbFeCo and its effects on the TM sublattice magnetization (MTM) were studied. The Kerr rotation angle (¿K) was low at all Co concentrations. The addition of Bi increases ¿TM, but has comparatively little effect on MTM. Bi increases ¿K in Gd-TM films, but decreases ¿K in Tb-TM films. This can be attributed to RE-Bi interactions. When both Tb and Gd were used (TbGdFeCoBi films), increasing the amount of Gd made ¿K rise at three times the rate of increase in TbGdFeCo films.