Microstructure and magnetic properties of NiZn ferrite thin films prepared by sol-gel method

Ti^4＋ substitution for Fe^3＋ in Ni0.5Zn0.5Fe2O4 （NZF） ferrite thin films were realized by sol-gel method and annealing at 600℃for 30 min in the air. Crystal structure and lattice constant determination was performed by X-ray diffractometer （XRD）. Surface microstructure was observed by scanning electron microscope （SEM） and atomic force microscope （AFM）, and the magnetic properties were measured by vibrating sample magnetometer （VSM）. XRD analyses of the samples show that Ni0.5＋xZn0.5TixFe2-2xO4 （NZTF） films with x varing from 0 to 0.15 in steps of 0.05 are composed of single phase with spinel structure. And the lattice parameter, particle size and the diffraction intensity of the films increase with substitution of Ti as the result of the larger radius ions entering the lattice. SEM and AFM show homogeneous grain size of each sample, but there is a few differences in grain size with different Ti-substitution contents. As the nonmagnetic Ti^4＋ substitutes Fe^3＋, both the saturation magnetization and coercivity decrease.