Low-Temperature Transitions in Tetramethylammonium Manganese Chloride

X-ray diffraction study of the ferroelectric phase transition of (CH3)4NCdBr3 (TMCB)

“…The structure has a strong one-dimensional character; it is built up from infinite linear chains of face-sharing MX6 octahedra, and the space between chains is occupied by the tetramethylammonium (TMA) groups, exhibiting orientational disorder of dynamic nature (Mangum & Utton, 1972;Tsang & Utton, 1976;Guillaume, Couzi & Bre, 1992).…”

On the ferroelectric phase transition in (CH3)4 NCdBr 3 (TMCB)

“…1 er OCTOBRE 1990, Classification Physics Abstracts 61.14F -61.SOE -64.70 - 77.80 The crystals with formula (CH3)4 NMX3 (M = Mn, Cd; X = Cl, Br) are hexagonal at room temperature, with space-group P63/m and Z = 2 formula units per unit-cell [1][2][3][4]. The structure is made of infinite linear chains of face-sharing MX6 octahedra and the space between the chains is occupied by the tetramethylammonium groups (TMA) exhibiting an orientational disorder of dynamic nature [5,6]. The chlorides (CH3)4 NMnC13 (TMMC) and (CH3)4 NCdC13 (TMCC) undergo a number of structural phase transitions, governed essentially by the reorientational dynamics of the TMA, and leading to different non-polar ordered phases with monoclinic symmetry, stable at low temperatures ( [5][6][7][8][9][10] and cited references).…”

Spin flop in a one-dimensional Heisenberg antiferromagnet(a)

“…True spin-flop transitions have been observed only below the three-dimensional ordering (Neel) temperature in other quasi-one-dimensional antiferromagnets, for example in tetramethylammonium manganese t:ichloride (TMMC) [3] and in CSNiCI S [4]. We be-ILeve that this is the first time eVLdence for spinflop behaviour has been found before the onset of long-range order in such a system.…”