Influence of rare earth ion (Y3+) on the magnetic and dc electrical properties of high density nanocrystalline MgCd ferrites

The samples having general formula Mg1−xCdxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) with 5% Y3+ addition were prepared by oxalate co-precipitation technique. The characterization was carried by XRD, SEM and FTIR techniques. The XRD confirms the cubic spinel structure with orthoferrite (YFe2O3) secondary phase. Average crystallite size and grain size lies in the range (28.86–32.66 nm and 0.37–0.69 μm). The grain size is calculated by linear intercept method and lies in the range of 0.37–0.69 μm. The FT-IR shows two absorption bands in the frequency range of 350–800 cm−1. The addition of Y3+ for Fe3+ forms a secondary phase on the grain boundaries and increases the saturation magnetization with respect to that of pure MgCd ferrites. The saturation magnetization, magnetic moment and coercive field is found to increase with cadmium content up to x = 0.4, obeying Neelʹs two sublattice model and decrease thereafter showing existence of non-collinear spin interaction. The saturation magnetization and coercivity shows size dependent behavior. Y–K type ordering is present in all samples except x = 1. The DC electrical resistivity increases while the Curie temperature (Tc) decreases, with increase in cadmium content. The DC resistivity of Y3+ added MgCd ferrite is higher than that reported for pure samples and for ceramic method. Activation energy in paramagnetic region is higher than that in ferromagnetic region.