Effect of the optimal annealing time on enhanced magnetic properties of Fe₃O₄ films

Abstract

The magnetic hybrid structure of a half-metallic ferromagnetic oxide and a non-magnetic oxide is promising for future spintronic devices. However, the ferromagnetic layer’s structural and magnetic characterizations must be improved urgently. Here, we report on the effect of annealing time on enhancing the structural and magnetic properties of Fe₃O₄ films. Radio-frequency magnetron sputtering was used to fabricate Fe₃O₄ thin films on a multilayer of MgO/Ta/SiO₂ at room temperature. As-grown Fe₃O₄ samples were annealed at the optimal temperature for various times. The structural and magnetic properties of Fe₃O₄ were observed by using atomic force microscopy, X-ray diffraction, and a vibrating sample magnetometer. The structural characterization of Fe₃O₄ thin films is significantly enhanced when increasing the annealing time. Moreover, the magnetization of Fe₃O₄ thin films is also highly improved compared to the bulk value. Our finding provides a highlight for the next generation of spintronics.