Structure, Morphology, Cation Distribution and Magnetic Properties of Cr3+-Substituted CoFe2O4 Nanoparticles

The present investigations deal with the effect of trivalent chromium ions (Cr3+) on structural and magnetic properties of nanocrystalline cobalt ferrite (CoFe2O4) nanoparticles. The samples of CoCrxFe2−xO4 (where x = 0.0 to 1.0 in step of 0.2) were successfully synthesized by citric acid-assisted sol-gel auto combustion method. Further, the prepared samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR) and pulsed field hysteresis loop technique for structural, morphological and magnetic properties analysis, respectively. XRD patterns showed the formation of single-phase cubic spinel structure with broad Bragg’s peak for all the samples. The value of lattice parameter was found to be decreased with chromium substitution x. Cation distribution studies revealed that Co2+ and Fe3+ occupied both A and B sites, whereas Cr3+ ions occupied only B site. SEM analysis of the prepared samples confirmed the nanocrystalline nature of the material. The two absorption bands belonging to spinel structure were observed in IR spectra. Saturation magnetization (MS), remanence magnetization (Mr) and coercivity (HC) was found to be decreased with increase in chromium substitution x.