Electronic and magnetic properties of the iron borate Fe2BO4

Polycrystalline Fe2BO4 was prepared by solid state reactions and its electr onic and magnetic properties were investigated by Mossbauer spectroscopy an d magnetization measurements. The Mossbauer spectra of Fe2BO4 below 270 K i ndicate the presence of Fe2+ and Fe3+ sites in the structure, in a ratio 1: 1. Above this temperature electron delocalization sets in between the dival ent and trivalent iron ions and Fe2.5+ states are observed. The temperature dependence of the Mossbauer spectra and magnetization measurements clearly show the onset of magnetic order below 155 K.