Synthesis, Characterization, Optical Properties, and Electron Paramagnetic Resonance for Nano Zn 0 . 5 Co 0 . 5 Fe 2 − x Pr x O 4

Nano ferrite samples of type Zn0.5Co0.5Fe2−x Prx O 4, 0 ≤ x ≤ 0.2, were prepared by co-precipitation method for different concentration of Pr ions at a calcination temperature of 823 K. The samples were characterized using x-ray diffraction and transmission electron microscope (TEM), UV spectroscopy, FTIR, and electron paramagnetic resonance (EPR). The increase in concentration of Pr ions shows a significant change in the formed nano ferrite particles size, degree of aggregation, energy band gap, and lattice parameters. X-band (9.24 GHz) EPR spectra at room temperature showed a decrease in the g factor as the Pr content was increased. Furthermore, the variation of the Pr3+ concentration in the samples led to different aggregation states, ranging from isolated nanoparticles with average crystal size of 28.5 to about 15 nm, as confirmed by x-ray diffraction and high-resolution transmission electron microscopy.