Heat-Treatment-Induced Compositional Evolution and Magnetic State Transition in Magnetic Chalcogenide Semiconductor...

Control of magnetic properties in diluted magnetic semiconductors (DMSs) using external stimuli is a prerequisite for many spintronic applications. Fe-doped chalcogenide semiconductors are promising candidate materials for future spintronic devices since they offer the possibility of magnetic switching by their fast and reversible transition between amorphous and crystalline phases. However, for many proposed applications, magnetic manipulation in crystalline DMSs without a structural change is highly desirable. Thus, the ability to externally control the magnetism of magnetic chalcogenide semiconductors without structural phase change is of significance to enhance their application potential. Here we find that the annealing process could induce an antiferromagnetic (AFM)-ferromagnetic (FM) transition in magnetic chalcogenide semiconductor GeFeTe epilayers without deteriorating the crystal structure. The impact of heat treatment on magnetization in Ge_1-xFe_xTe film depends on Fe concentration. The present data indicate that the AFM-FM transition originates from the evolution of Fe phase composition. This study gives an insight into the correlation between Fe phase composition, electronic structure, and magnetism in GeFeTe thin films.