Iron phosphate (Fe203-P205) glasses with a high Fe2O3 content are particularly interesting in that they exhibit short range anti-ferromagnetic (speromagnetic) ordering at low temperatures. Neutron scattering techniques have been employed to investigate the atomic and magnetic structure and dynamics of four iron phosphate glasses, as a function of their nominal composition between 30 and 44 mol% Fe2O3, and the data are compared with earlier structural models in which the Fe3+ cations are either tetrahedrally or 6-fold coordinated by oxygen. Fe2+ cations are also found to be present in 6-fold coordination. Neutron magnetic diffraction experiments yield information concerning the Fe-Fe distances and confirm the speromagnetic nature of the magnetic ordering, whilst a measurement of the magnetic inelastic scattering from vitreous 40Fe2O3.60P2O5 reveals the presence of dispersive magnetic excitations centred on the first magnetic diffraction peak at 0.82 A-1. It is concluded that all four glasses have structures that are much more complicated than the above models would suggest and include Fe3+ cations in both tetrahedral and octahedral coordination.
