Microstructure and magnetic properties of CoFe2O4 thin films deposited on Si substrates with an Fe3O4 under-layer

The microstructure and magnetic properties of cobalt ferrite thin films deposited by the sputtering method on an Fe3O4 under-layer were investigated at different post-annealing temperatures. Results show that the Fe3O4 under-layer can accelerate the grain growth of cobalt ferrite films due to the phase transformation of the Fe3O4 under-layer at about 400°C–500°C. By introducing the Fe3O4 under-layer, cobalt ferrite nanocrystalline thin films with high coercivity can be obtained at lower post-annealing temperatures.