The magnetic properties of NixZn1−xFe2O4 films fabricated by alternative sputtering technology

NixZn1−xFe2O4 (0.2≤x≤0.7) thin films with various compositions are prepared by alternative sputtering technology from the two targets with the composition NiFe2O4 and ZnFe2O4. The films are deposited on (1 1 1) Si substrates directly and buffered with ZnFe2O4 underlayer, respectively, at room temperature and then annealed in air at 850 °C. For unbuffered films with the increasing of Zn content, the saturation magnetization Ms increases firstly and then decreases when x=0.40 the Ms reaches the maximum value about 400 emu/cc, while the coercivity Hc decreases monotonously. The films grown on substrates with ZnFe2O4 underlayer exhibit better magnetic properties than those deposited on directly Si substrates which indicates the importance of lattice match and structural similarity between the film and the underlayer.