CRYSTALLOGRAPHIC STUDY OF YFE2D3.5 BY X-RAY AND NEUTRON POWDER DIFFRACTION

Crystallographic properties of YFe2D3.5 deuteride have been studied by X-ray and neutron powder diffraction, At 350 K, it crystallizes in th e R-3m space group (Z = 6) with a = 5.540(1) Angstrom and c = 13.568(2 ) Angstrom. The location of deuterium atoms has been achieved in the p aramagnetic state (T = 350 K), YFe2 and YFe2D3.5 are ferromagnetic but deuterium absorption decreases the Curie temperature from 560 to 345 K. At room temperature, the neutron diffraction pattern of the deuteri de exhibits a sharp rhombohedral distortion which is compared to that of the ErFe2Dx compound. (C) 1997 Academic Press.