CRYSTAL AND MAGNETIC-STRUCTURE OF STOICHIOMETRIC YFE2O4

The crystal structure of stoichiometric YFe2O4 powder has been studied by high-resolution neutron diffraction at room temperature, 225 K and 80 K. Rietveld refinements of the diffraction patterns give reasonabl e fits with space group R ($) over bar 3m (hexagonal) for room tempera ture, and with P-$ over bar 1 (triclinic) for 225 K. However, the patt ern obtained at 80 K cannot be fitted at all with the same triclinic s ymmetry, indicating that the structure is much more complicated. The m agnetic reflection has been separated from those complex nuclear peaks by the polarization analysis. The magnetic structure is also fairly c omplicated both at 225 and at 80 K.