Study of phase transformations in YFe2D1.75 deuterides by in situ neutron diffraction

At 300 K YFe2D1.75, crystallizes in a large cubic structure (I (4) over bar 3m) with a = 1.536 nm. At 440 K YFe2D1.75, undergoes a reversible structur al order-disorder transition into a C15-type cubic structure (Fd (3) over b ar m) with n = 0.770 nm and a random distribution of D atoms on the 96 g si te. At 555 K the deuteride decomposes rapidly into YD2 and alpha-Fe. (C) 20 00 Elsevier Science B.V. All rights reserved.