“…For instance, it has been reported that the C15 Laves phases AB 2 compounds having an atomic size ratio larger than 1.37 amorphize by hydrogenation [15], while those having a smaller one do not amorphize. Structural changes of C15 Laves phases RFe 2 in a hydrogen atmosphere have extensively been investigated [8][9][10][11][12][13][14][16][17][18][19][20][21][22], but those of C15 Laves phases RM 2 (M = Co, Ni, and Mn) have slightly been done [2,[23][24][25][26][27]. Recently, the present authors have systematically investigated structural changes of C15 Laves phases DyM 2 (M = Fe, Co, and Ni) having an atomic size ratio above 1.37 by the thermal analysis in a hydrogen atmosphere and showed the formation of the single-phase amorphous hydrides a-DyM 2 H x [22,26,27].…”