Magnetic properties of the mined spinel CoFe2-xCrxO4

The crystal and magnetic properties of the Cr-substituted disordered spinel system CoFe2-xCrxO4 (x = 0-1.6) are investigated by means of X-ray, magnetization, Mossbauer effect and AC susceptibility measurements Variations of magnetic moment per formula unit measured at 80 K with Cr-content obtained from magnetization and Mossbauer data for x = 0-0.6 display a discrepancy between them, thus exhibiting a significant canting on the B-site which is satisfactorily explained on the basis oi the non-collinear spin ordering model of random canting. Magnetization and Mossbauer results also show a sudden change near x > 0.6 indicating a change in magnetic structure from non-collinear to possibly collinear for x = 0.8-1.6. The AC susceptibility indicates a paramagnetic --> unstable ferrimagnetic --> cluster spin glass-type transition as the temperature is lowered for I = 0-1.2. The further increase in x from x > 1.2 increases frustration and disorder in the system supressing the ferrimagnetic ordering and the system approaches a cluster spin glass-type ordering at x = 1.4-1.6 as reflected in AC susceptibility and Mossbauer spectra.