Effects of annealing temperature on the structure and static magnetic properties of NiZnCo ferrite thin films

The Ni0.22Zn0.52Co0.03Fe2.23O4 ferrite thin films are deposited on Si (100) substrate by a radio-frequency magnetron sputtering method. The structure and magnetic properties of NiZnCo ferrite thin films with different annealing temperatures (600 °C, 700 °C, 800 °C and 900 °C) have been investigated. The secondary impurity phases of Fe2O3 and ZnO slowly disappeared with annealing temperature up to 800 °C. But, there are some FeSiO3, Zn2SiO4 and SiO2 impurity phases formation when the annealing temperature is 900 °C. The average grain size and surface roughness increased with annealing temperature up to 800 °C and then they decreased at 900 °C. The saturation magnetization gradually increases with annealing temperature up to 800 °C and then it decreases at 900 °C. Meanwhile, the coercivity monotonically decreases with annealing temperature up to 900 °C.