Synthesis and magnetic properties of amorphous Fe-Y-B thin films

Amorphous Fe-Y-B thin films have been successfully fabricated by direct-current magnetron sputtering, and the effects of annealing treatment on the microstructure and magnetic properties, especially coercivity and magneto-impedance ratio, were investigated systematically. After low-temperature heat treatments (below 673 K), films still remain amorphous structure and their magnetic properties were largely enhanced due to stress release, e.g., the maximum magneto-impedance ratio increases from about 5.6-46.6% and the coercivity decreases from about 7.7-2.2 Oe for as-deposited film and the film annealed at 573 K for 1 h, respectively. After high-temperature heat treatment at 673 K, crystallization occurs, deteriorating magnetic properties (magnetic softness and magneto-impedance features) of the film. The Fe-Y-B thin film annealed at 573 K for 1 h, possessing good magneto-impedance effect and soft magnetic properties, might have potential application in micro-sized magnetic actuators.