X-RAY, SEM AND MAGNETIC-PROPERTIES OF MG-CD FERRITES

Magnetic properties of polycrystalline ferrites CdxMg1-xFe2O4 (x = 0.0 , 0.2, 0.4, 0.6, 0.8 and 1.0) are studied for their saturation magneti sation n(B), AC susceptibility chi and initial permeability mu(i). Dep endence of saturation magnetisation on Cd2+ content suggest that A-B a nd B-B superexchange interactions are comparable in strength. Neel's t wo sublattice model is applicable upto x less than or equal to 0.4 whi le Y-K three sublattice model is predominent for x > 0.4. Variation of AC susceptibility and initial permeability with temperature revealed the long-range ferrimagnetic ordering in the compounds having x less t han or equal to 0.4. The sample with x less than or equal to 0.2 exhib its, multidomain structure, while for x = 0.4 shows SD-SP transition a nd for x greater than or equal to 0.6 the samples show S-P domain stru cture. Low-frequency dispersion of initial permeability suggests domai n wall displacement. Addition of Cd2+ results in the sharp decrease in crystallographic phase transition temperature T-p and Curie temperatu re T-c of the samples.