Electrical and magnetic studies of iron (III) vanadate

Iron(III) vanadate (FeVO4) is an n-type semiconductor between 300 and 800 K. Electrical conduction in this phase occurs due to small deviation from oxygen stoichiometric composition. The mechanism of electrical transport is of a thermally activated hopping of charge carriers (electrons) on equivalent iron lattice sites. The FeVO4 obeys Curie-Weiss law between 80 and 300 K. The measured magnetic moment (μ eff) of Fe3+ ion in FeVO4 is 5·270 BM at 298 K, which is lower than theμ spin only value. The predominant exchange interactions are the weak 90° M-O-M superexchange and M-O-O-M super-super-exchange. The negative Weiss constantϑ=− 30 K of the phase indicated the possibility of an antiferromagnetic ordering of the iron(III) vanadate lattice. The IR absorption spectrum of FeVO4 gave bands at 990, 900, 825 and 725 cm−1 due to the presence of distorted VO4 polyhedra of the lattice.