Study of structural, electrical and magnetic properties of Cr doped Ni-Mg ferrite nanoparticle

We have reported the effect of Cr3+ ion doping on the structural, ac transport and Mossbauer spectral studies of ferrite nanoparticles Ni0.5Mg0.5Fe2 Chi Cr Chi O4 (Chi = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) prepared by sol-gel auto combustion technique. The micro-structural studies of the samples were obtained by using scanning electron microscopy (SEM). The dependence of Mossbauer parameters, viz., line width, isomer shift, quadrupole splitting and hyperfine magnetic field on Cr3+ substitution have been analysed. Hyperfine magnetic field and isomer shift values decreases whereas line width increases with Cr3+ substitution. Rietveld refinement and Mossbauer spectroscopy studies reveal that the Ni0.5Mg0.5Fe2 xCrxO4 with various concentrations of x belongs to mixed spinel structure. Neel's molecular field model is used to explain the variation of hyperfine magnetic field with increasing Cr3+ substitution