EPR studies of Cd substituted Mn Zn nanoferrites

Abstract

Nanoparticles of Mn0.5Zn0.5-xCdxFe2O4 with x varying from x = 0.0 to 0.3 were prepared by wet chemical co-precipitation method. The structural and magnetic properties were studied by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and Electron Paramagnetic Resonance (EPR) technique. The lattice constant increases with increase in Cd content. This increase in the lattice constant is due to larger ionic radii of the Cd 2+ (0.97 A) ions as compared to Fe 3+ (0.64 A) ions. The intensities of the planes (220) and (440), increases with increasing Cd 2+ ion concentration. This shows that Cd 2+ ions occupy tetrahedral A sites and octahedral B sites in the nano dimension against their chemical preference for A site. The line width (ΔHpp) and the g value of the Electron paramagnetic resonance (EPR) signal decreases with increase in the Cd content. The magnetic moment of all the samples up to x = 0.2 calculated from EPR studies are lower when compared to the theoretical values. This lower value of magnetic moment confirms the existence of non collinear magnetic structure arising due to significant amount of spin disorder existing at B site.