Accepted Friday Nov 06, 2009
FeVO4 has been studied by heat capacity, magnetic susceptibility, electric polarization and single crystal neutron diffraction experiments. The triclinic crystal structure is made of S-shaped clusters of six Fe3+ ions, linked by VO43- groups. Two long-range magnetic ordering transitions occur at TN1=22K and TN2=15K. Both magnetic structures are incommensurate and below TN2, becomes weakly ferroelectric coincidentally with the loss of the collinearity of the magnetic structure in a very similar fashion than in the classical TbMnO3 multiferroic material. However we argue that the symmetry considerations and the mechanisms invoked to explain these properties in TbMnO3 do not straightforwardly apply to . Firstly, the magnetic structures, even the collinear structure, are all acentric so that ferroelectricity in is not correlated to the fact magnetic ordering is breaking inversion symmetry. Regarding the mechanism, has quenched orbital moments that questions the exact role of the spin orbit interactions.