Structural, magnetic, and dielectric properties of Ni/Zn co-substituted CuFe2O4 nanoparticles

Microstructural, magnetic and dielectric properties of NixCu1-3xZn2xFe2O4 nanoparticles were investigated by various techniques. Samples were structurally analyzed using X-ray diffraction and Rietveld refinement. A structural phase transition from a tetragonal spinel structure with space group I41/amd to a cubic spinel structure with space group Fd3‾m was observed by increasing the Ni/Zn co-substitution and also the lattice parameter increases. These structural results were confirmed by Raman and Fourier-transform infrared spectroscopy. The magnetic hysteresis loops of the samples indicated a magnetic phase transition from the hard to soft ferrimagnetic and the magnetization values increase for x up to 0.2, and then it decreased. The results of impedance analysis indicated that the increase in the mobility of charge carriers in the samples with x between 0 and 0.15 can be attributed to the reduced porosity and surface area, because a smaller number of defects commonly would block the movement of carriers.