Novel Existence of canted Spins on Octahedral Sites of CdxMg1-xFe2O4 Ferrites as a Third Active Mode of Vibrations

Polycrystalline ferrites CdxMg1-xFe2O4 (x = 0.0, 0.2, 0.4, 0.6 and 1.0) were prepared by standard ceramic technique and characterized by X-ray, SEM, IR absorption and Mssbauer technique. X-ray analysis shows that the samples have single-phase cubic spinal structure. SEM study revealed that all ferrite samples are crack-free having well packed continuous grain structure with well defined grain boundaries. Two distinct absorption bands 1 and 2 in MgFe2O4 arising from intrinsic vibrations on tetrahedral A-site and octahedral B-site is observed. Addition of Cd2+ in the host lattice resembles the shifting of& broadening of 2 up to x =0.4, While for x 0.6 third active mode of vibration 3 in the frequency range 335 cm-1 to 340cm-1, well separated from 2, is clearly observed. Saturation magnetization was determined for obtaining information about the Yaffet-Kittle angles at 300 K. The variation of nB with Cd2+ content suggested the existence of predominating Y-K model for x 0.6, while Neels two Sub-lattice models applicable up to x 0.4. The canting of spins explains the fundamental third active mode of vibrations in Mg-Cd ferrites satisfactorily.