Nucleation near the tricritical point of BaTiO3

Time-resolved polarization measurements on BaTi${\mathrm{O}}_3$ for pressures between 1 atm and the tricritical pressure $P_t\equiv 32$ kbar reveal a delay between the application of an electric field and the rise of polarization towards its equilibrium, ferroelectric value. The delay decreases exponentially with the difference between applied electric field and the field at which the equilibrium ferroelectric-paraelectric transition occurs. A model which includes long-range elastic and dipole interactions present in single crystals gives a qualitative description of the delay time.