Structural and Magnetic Properties of CoFe2O4 Thin Films via Sol-Gel Method

Abstract

Cobalt ferrite (CoFe2O4) thin films have been prepared on Si (001) substrates, with different calcined temperatures (Tcal=400°C~800°C). The films structure was studied by X-ray diffraction (XRD) and their surface was examined by scanning electron microscopy (SEM). The magnetic properties were measured with a vibrating sample magnetometer (VSM). For low calcined temperatures, the films presented a mixture of a CoFe2O4phase, with the cubic spinel structure, and cobalt and iron antiferromagnet oxides with CoO and FeO stoichiometries. As the calcined temperature increased, the CoO and FeO relative content strongly decreased, so that for Tcal=800°Cthe films were composed mainly by polycrystalline CoFe2O4. The magnetic hysteresis cycles measured in the films were horizontally shifted due to an exchange coupling field originated by the presence of the antiferromagnetic phases.