Microscopic and macroscopic magnetic properties of MgAlxCrxFe2−2xO4 spinel ferrite system

In order to study the effect of co-substitution of Al3+ and Cr3+ for Fe3+ in MgFe2O4 on its structural and magnetic properties, the spinel system MgAlxCrxFe2−2xO4 (x = 0.0–0.8) has been characterized by X-ray diffraction, high field magnetization, low field a.c. susceptibility and 57Fe Mo¨ ssbauer spectroscopy measurements. Contrary to the earlier reports, about 50% of Al3+ is found to occupy the tetrahedral sites. The system exhibits canted spin structure and a central paramagnetic doublet was found superimposed on the magnetic sextet in the Mo¨ ssbauer spectra (0.5 > x > 0.2). Thermal variation of a.c. susceptibility exhibits normal ferrimagnetic behaviour. C 2005 Springer Science + Business Media, Inc.