Microstructure and magnetic properties of melt-spun (Tb_0.33Fe_0.67)_1-xB_x alloys

Structure and temperature dependence of magnetization of melt-spun (Tb_0.33Fe_0.67)_1-xB_x (x = 0, 0.02, 0.05. 0.1 and 0.15) alloys were investigated using X-ray diffractometry and magnetometry. The alloy samples consist of nanocrystalline TbFe₂ cubic Laves phase and an amorphous phase. As the B content increases, the fraction of amorphous phase increases and the magnetization decreases. Thermomagnetization curves obtained with an external magnetic field of 10 kOe show that the magnetization first increases, reaches a maximum value at around 100 K and then decreases with increasing temperature. The appearance of the peak can be explained by the increased anisotropy in amorphous and crystalline TbFe₂ phases at low temperature.