Magnetic anisotropy and other studies in amorphous Tb-Fe films

Magnetic properties of RF sputtered Tb_xFe_1-x films with 132O₃ about 15 nm thick. B-H and Kerr loops were studied. Torque measurements were made in the temperature range 20-300 K with a maximum applied field of 12.5 kOe. The experimental data as regards M, H_c, Theta _k and K_u are in general agreement with published data. Perfect rectangular loops were obtained for 2026Fe₇₄, K_u increased rapidly as T was lowered and below 80 K, measurements were no longer possible due to the lack of magnetic saturation. For Tb₂₀Fe₈₀, with a T_comp approximately=150 K, torque curves show anomaly in the neighborhood of T_comp. The result are discussed leading to the conclusion that stress effects have a dominant role to modify K_u, particularly at low T. The Tb moment at 4 K is calculated to be 7.3+or-0.6 mu _B.