Nanocomposites of ZnO mixed with different Ni-ferrite contents: Structural and magnetic properties

In this study two methods, solid-state (S?S) and sol-gel (S-G), were used to prepare ZnO/NiFe2O4 (assigned as ZnO/NF) hetero nanocomposites with different NF contents (0, 5, 10, 15, 20 and 25 wt %). The prepared composites were investigated using XRD, EDX, HR-TEM to study their structural and morphological properties. The obtained XRD patterns have been analyzed by employing the Rietveld refinement technique. The results confirmed the formation of ZnO/NF composites with individual characteristic peaks corresponding to both ZnO and NF, and no impurities were detected. HR-TEM images showed nearly spherical particles for all samples with an average particle size of 23?72 nm. The magnetic parameters were estimated from the measured hysteresis loops using a vibrating sample magnetometer (VSM). The samples showed typical ferromagnetic behavior with different saturation magnetization (Ms) and coercivity (Hc) depending on the NF contents and the preparation route. The values of initial permeability (?i) showed independent behavior on the frequency and its correlation with saturation magnetization Ms and particle size was discussed. The study may help in enhancing the magnetic properties of ZnO by doping with NF. The comparison between two preparation techniques may provide optimum conditions to be used in development of multiphase materials for various applications.