Tuning of structural phase, magnetic spin order and electrical conductivity in mechanical alloyed material of α-Fe2O3 and α-Cr2O3 oxides

Abstract

The solid solution of Fe2-xCrxO3 (x = 0.2–0.8) has been prepared by mechanical alloying of α-Fe2O3 and α-Cr2O3 oxides and subsequent heat treatment. The lattice structure and properties of the heat treated samples differed from the as-alloyed samples. High quality synchrotron X-ray diffraction patterns have shown an inhomogeneous structure of α-Fe2O3 and α-Cr2O3 phases in as-alloyed samples. The heat treatment has homogenized structure and successfully incorporated the Cr atoms into lattice sites of the Fe atoms in α-Fe2O3. The soft ferromagnetic properties with signature of two Morin transitions have been observed in the as-alloyed samples. A canted antiferromagnetic spin order has appeared in the heat treated samples, irrespective of Cr content in Fe2-xCrxO3. The spin flop transition has been observed at a critical magnetic field that depends on Cr content in the system. The Mössbauer spectra at room temperature have suggested a non-uniform distribution of magnetic spin order of Fe and Cr ions in rhombohedral structure. The electrical conductivity of the heat treated samples has shown enhancement with the increase of Cr content in α-Fe2O3 structure.