Author/Authors :
Drozd، نويسنده , , V. and Kuo، نويسنده , , H.T. and Bagkar، نويسنده , , N. and Mylswamy، نويسنده , , S. and Liu، نويسنده , , R.S. and Paul-Boncour، نويسنده , , V. and Marchuk، نويسنده , , I. and Filipek، نويسنده , , S.M. and Chou، نويسنده , , C.C. and Sun، نويسنده , , C.P. and Yang، نويسنده , , H.D. and Chen، نويسنده , , J.M.، نويسنده ,
Abstract :
YFeMn alloy exposed to high hydrogen pressure transforms into hydrides with hydrogen concentration higher than 5 H p.f.u. Rietveld’s refinement of XRD data indicates the presence of two hydrides corresponding to YFeMnH5.46 and YFeMnH5.02 with the cubic structure of a parent intermetallics. YFeMnH5.46 was found to be unstable. It desorbs hydrogen yielding YFeMnH5.02 (referred as YFeMnH5) which was used for further X-ray absorption near edge structure (XANES) and magnetic measurements. Based on XANES studies at the Mn and Fe K-edges, Mn and Fe atoms in YFeMn alloy are in the metallic state, whereas they exhibit partially anionic character in the hydride. Hydrogenation influences the valence state of Mn and Fe in YFeMn, modifies the density of states (DOS) near the Fermi level and induces an increase of the Curie temperature and a decrease of magnetization at 5 K.
Keywords :
Hydrides , magnetization , XANES , Laves phases
