Electrical, magnetic and Mossbauer properties of cadmium-cobalt ferrites prepared by the tartarate precursor method

Six samples of the system Cd1-xCoxFe2O4 were prepared by the tartarate prec ursor method with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0. The formation of fer rispinels were studied by X-ray powder diffraction, infrared spectroscopy, electrical conductivity, thermoelectric power, magnetic hysteresis, initial magnetic susceptibility and Mossbauer spectroscopy. The data of the temper ature variation of the direct current electrical conductivity showed a defi nite kink (similar to 390 degreesC) except x = 0.0 and 0.2, which correspon ds to the ferrimagnetic to paramagnetic transitions. Magnetic properties of the samples with x greater than or equal to 0.6 showed definite hysteresis loops. The observed low magnetic moment can be explained in terms of the n on collinear spin arrangement. A well defined hyperfine Zeeman spectra are observed for samples with x greater than or equal to 0.6 at room temperatur e and resolved into two sextets corresponding to octahedral and tetrahedral sites. The electrical, magnetic and Mossbauer properties suggest that, a c anted spin arrangement upto x = 0.8 and Neel's configuration above this com position. The probable ionic configuration for the system is suggested as (Cd-1-x(2+) Fe-x(3+)) (A) [Fe2-x3+Cox2+](B) O-4(2-). (C) 2001 Kluwer Academic Publishers.