Phase relations in the “FeO–V2O3” system at 1473 K and the magnetic properties of spinel phase Fe3-xVxO4

Abstract Phase relations within the “FeO–V2O3” oxide system at 1473 K in the oxygen partial pressure range from 5.98 × 10−15 to 2.39 × 10−8 atm were determined using the chemical equilibrium and quench method followed by XRD and EPMA measurements. There exist four univariant equilibria and two invariant equilibria in the “FeO–V2O3” oxide system. According to the determined phase relations, a phase diagram of this system was constructed by plotting log ( p O 2 / a t m ) versus the molar ratio of V/(Fe + V). Furthermore, the magnetic properties of a series of spinel Fe3-xVxO4 compounds prepared under different oxygen partial pressures were measured at room temperature. It was revealed that Fe3-xVxO4 compounds with Fe/V larger than 1.2 are magnetic, and their magnetizations increase remarkably with the increasing of the molar ratio of Fe/V. In addition, for the Fe3-xVxO4 compound with fixed molar ratio of Fe/V, its saturation magnetization increases slightly with the increasing of the oxygen partial pressure in which the compound was prepared.