Generalized relationship between transition temperature and transition pressure in TGSe

Digital hysteresis loops were measured on triglycine selanate at small temperature intervals close to T-C for given hydrostatic pressures. Transition temperatures were read by the spontaneous polarization and tricritical isotherm methods. Under the generalized equation, the expression [T(p)/T-C(p = 0) + p/p(C)(T = 0) - 1] must be equal to zero at the transition. This determines the (tri)critical point equation of state for pressure and temperature for TGSe. The data obtained were compared to data from literature on other ferroelectrics.