Annealing Temperature Dependent Structural and Magnetic Properties of Ni−Cu−Zn Nanoferrites

The effect of annealing temperature on the structural and the magnetic properties of Ni0.5Cu0.25Zn0.25Fe2O4 (Ni−Cu−Zn) nanoferrites synthesized using an oxalic-based precursor method was investigated in detail. A single phase of the Ni−Cu−Zn ferrite was observed from X-ray diffraction (XRD) data. From the XRD analysis, the grain size was found to increase with increasing annealing temperature from 500 to 800 ◦ C whereas the lattice constant was found to decrease. The scanning electron microscope (SEM) analysis showed nanosize grains in the prepared samples. The magnetization analysis showed that the saturation magnetization (Ms) increased with increasing annealing temperature due to the increasing grain size whereas the coercivity (Hc) and the remanence magnetization (Mr) showed decreasing behaviors. The Curie temperature (TC) was measured for all samples. As the grain size increased the Curie temperature was also observed to increase. For these samples, the Curie temperatures lies between 426 K to 504 K. The dielectric constant (ε ) was observed to be higher for these samples. The dielectric loss tangent increase slowly with increasing frequency till a particular frequency, after that it slowly decreased. Therefore the annealing temperature was observed to have a significant effect on the structural, magnetic and electrical properties of synthesized Ni−Cu−Zn ferrite.