Structural and Magnetic Properties of Low D Content YMn2 Deuteride

Symmetry analysis of hydrogen related structural transformations in Laves phase intermetallic compounds

“…For positions 16d, all star of k vector (0,0,1) and representation τ 3 , which lead to P-43m group the Table 7 Position in Fd-3m Position in P-43m Magnetic moments symmetry analysis indicates the non-collinear and non-planar structure with magnetic moments localised on 12i positions and no magnetic moments on the 4e positions. This results stay in good agreement with supposition made in [13], that one should expect different moments localised on different orbits of Mn atoms, what was not confirmed experimentally. The detailed description of resulting magnetic structure is given in the Table 7.…”

“…For the case with k = (0,0,1) the comparison of experimental data interpretation for YMn 2 H 1.15 [13] and results of the symmetry analysis indicate qualitative agreement. The splitting on the subgroup orbits and the number of orbits with high, middle and low hydrogen occupation are the same, but positions with these types of occupations are different.…”

“…For the case of k = (0,0,0) the symmetry analysis indicates the possibility of displacements of M atoms following to the mentioned above symmetry groups as given in Table 2, and no displacements of R atoms, because the τ 8 representation is not allowed for these positions. The structure indicated for YMn 2 H 1.15 by Latroche et al [13] with symmetry group P-43m occurs possible in the multi-k phase transition, with all three arms of k vector: k 1 = (0,0,1), k 2 = (0,1,0,) and k 3 = (1,0,0). The representation active in this phase transition, and set of coefficients following to P-43m group are: two-dimensional IR τ 3 and (c,c;c,c;c,c).…”

“…In this work, the additional symmetry analysis is given for possible types of hydrogen atoms ordering over the 32e interstitial sites (AB3 tetrahedra), and one of possibilities of hydrogen ordering with k = (0,0,1) following to the P-43m space group indicated by Latroche et al [13].…”

Comparison of the influence of hydrogen on the magnetic properties of RMn2 and RFe2 Laves phase compounds

“…A neutron diffraction study was undertaken on YMn 2 D 1. 15 and YMn 2 (H 0.64 D 0.36 ) 1.15 in order to separately study the magnetic and the deuterium order, which occur at the same temperature [15,19,20]. The crystal symmetry is lowered to a simple cubic structure (P-43m space group) with three Y and two Mn sites; the deuterium atoms occupy four of the six possible interstitial Since T N decreases under an external pressure [11], the rise of T N upon H absorption can be considered as a negative pressure effect.…”