Effects of Annealing on Coercivity and Magnetization of Terfenol-D Thin Films

Terfenol-D (Tb0.3Dy0.7Fe2) film with low coercivity and high magnetization in weak magnetic fields is essential for its application as a weak magnetic sensor. In this article, an annealing method is proposed to optimize the coercivity and magnetization of the deposited Terfenol-D film. The magnetization could be improved by releasing compressive stress and increasing saturation magnetization. The coercivity decreases and then increases sharply due to partial crystallization with the annealing temperature increasing. The low coercivity of 12.6 Oe and high magnetization at 100 Oe of 0.29 eμg are obtained with the annealing temperature at 525 °C. Further increment in annealing temperature does not contribute to coercivity and magnetization. The annealed film could promote the application of Terfenol-D in weak magnetic sensors.