Influence of substrate type on the property of nickle–zinc ferrite thin films

Ni0.45Zn0.5Mn0.05Fe2O4 ferrite thin films (NZFs) were deposited on different substrates [Si(100), Si(111) and MgAl2O4(100)] by radio frequency (RF) magnetron sputtering method. The phase structure, surface morphology and magnetic property of NZFs were investigated using the X-ray diffractometer (XRD), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM), respectively. All the NZFs deposited on three kinds of substrates possess spinel structure, while only the film deposited on MgAl2O4(100) substrate [NZF/MgAl2O4(100)] has a preferred orientation along the direction of (100) because of the strong inducing effect of substrate. NZF/MgAl2O4(100) owns smoother surface than that of the film deposited on Si(111) substrate [NZF/Si(111)]. However, NZF/MgAl2O4(100) possesses larger grain size and much inhomogeneous distribution of grain size than that of NZF/Si(111). NZF/MgAl2O4(100) has the greatest saturation magnetization (Ms) of 345 kA/m and coercivity (Hc) of 5.80 kA/m. According to the stress model, the coercivity of NZFs deposited on various substrates has been calculated and discussed, which matches with the experiment results.