Thermal annealing effect on magnetism and cation distribution in disordered ZnFe₂O₄ thin films deposited on glass substrates

The effect of thermal annealing on magnetic properties has been investigated for disordered zinc ferrite (ZnFe₂O₄) thin films deposited on silica glass substrates using a sputtering method. The magnetization at room temperature is enhanced by annealing at relatively low temperature such as 300 °C and decreased by annealing at higher temperatures. X-ray absorption near edge structures indicate that ZnFe₂O₄ thin film annealed at 300 °C possesses disordered cation distribution similar to that for as-deposited thin film. It is presumed that the enhancement of magnetization by annealing at 300 °C is due to precipitation of disordered ZnFe₂O₄ crystal from an amorphous matrix formed in the as-deposited thin film.