Structural and magnetic properties of low D content YMn2 deuteride

The structural and magnetic properties of YMn2D1.15 have been investigated by temperature-dependent neutron diffraction, Magnetic and deuterium orders appear below T-c = 217 K, To separate both effects and to study only magne tic ordering, hydrogen atom contribution was cancelled by preparing the com pound YMn2(H0.64D0.36)(1.15). A noncollinear magnetic structure with 3.1 mu (B)/Mn is observed, Finally the low-temperature structure was fully solved taking into account both deuterium and magnetic contributions. Whereas the deuterium atoms are randomly distributed over all the 96g sites (Fd (3) ov er barm) above 217 K, only 12i sites in space group P (4) over bar 3m are o ccupied at low temperature. (C) 2000 Academic Press.