The effect of hydrostatic pressure on the ferroelectric phase transition in [NH2(CH3)2]3[Sb2Cl9]

The effect of hydrostatic pressure on the ferroelectric phase transition temperature in [NH2(CH3)(2)](3)[Sb2Cl9] (DMACA) has been studied by electric permittivity measurements at pressures up to 400 MPa. The pressure - temperature phase diagram is given. The phase transition temperature (T-c) increases with increasing pressure up to 150 MPa, passes through a maximum and then decreases with a further increase of pressure. The unexpected nonlinear decrease in T-c with pressure increasing above 150 MPa suggests that the mechanism of ferroelectric phase transition in DMACA is different from hitherto assumed. (C) 2004 Elsevier Ltd. All rights reserved.