An investigation of structural and magnetic properties of Cr–Zn ferrite nanoparticles prepared by a sol–gel process

Cr x Zn Fe2−x O4 (with x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) spinel ferrite nanoparticles have been synthesized via sol–gel method. The precursor compound was calcined at a temperature of 900 °C for 3 h. The aim of this study was to investigate the effect of Cr3+ ion substitution on the structural and magnetic properties of Cr–Zn ferrite. The size, shape, and chemical state of the synthesized powders were structurally characterized by powder XRD, SEM, TEM, HRTEM, SAED, energy-dispersive X-ray analysis (EDAX), and Fourier transform infrared spectroscopy (FTIR) spectral techniques. The XRD pattern of Cr–Zn ferrite provides information about single-phase formation of spinel structure with cubic symmetry. Both crystallite size and lattice parameter decrease with increasing Cr content. Formation of spinel structure is affirmed by using FTIR and FTIR spectra which shows that the bands υ1 and υ2 are found to shift gradually toward the higher frequency side with substitution of Cr, which have been attributed to the decrease in the lattice constant. SEM and TEM micrographs demonstrated that nanoparticles with narrow size distribution were obtained. The average grain size was found to be in nanometer range and of the order of 43–63 nm obtained using TEM images. Compositional stoichiometry was confirmed by EDAX technique. The magnetic properties of synthesized chromium-substituted Zn ferrite nanoparticles were studied using vibrating sample magnetometer at room temperature under the applied magnetic field of 15 KG. The result indicated that the amount of Cr contents significantly influenced the crystal morphology and structural and magnetic properties of Cr-doped Zn ferrite nanoparticles.