Anomalies in hysteresis properties of Fe20Ni80/Tb-Co films with unidirectional anisotropy

摘要

Specific features of magnetization process in permalloy soft magnetic layer exchange coupled to an amorphous ferrimagnetic Tb-Co layer with strong in-plane magnetic anisotropy were investigated. Anomalous large variations in coercivity H-c and unidirectional anisotropy field He versus temperature T and annealing temperature T-a dependencies were observed. The changes in Hc and He were shown to be reversible for temperature range 5-300 K and irreversible for annealing temperatures 400-650 K. A critical role of a nonmagnetic spacer in the H-c(T) and H-e(T) formation were demonstrated. In conclusion simple explanation based on an assumption of thermally-induced variation of the interlayer magnetic boundary position and interdiffusion process was proposed. (C) 2015 Elsevier B.V. All rights reserved.