EFFECTS OF HYDROSTATIC-PRESSURE ON THE SUCCESSIVE PHASE-TRANSITIONS IN FERROELECTRIC [N(CH3)4]2COCL4 AND [N(CH3)4]2ZNCL4

The hydrostatic pressure effect on the stability of I, II, III, IV and V phases in {N(CH3)4}2 CoCl4 is found to be quite similar to that of the corresponding I, II, III, VII and IV phases in {N(CH3)4}2ZnCl4; the ferroelectric phase III disappears at 600 bar for Co-salt and at 1150 bar for Zn-salt, and a new phase VII in Zn-salt induced by pressures above 400 bar corresponds to the phase IV in Co-salt which has already appeared at 1 atm. © 1979.