Pressure-induced phase transitions of perovskite ferroelectric crystals: comparison of hydrostatic and 1D compression pressure

The effects of hydrostatic and one-dimensional (1D) compression pressure on the phase transition of perovskite ferroelectric crystal were comparably investigated via the measurement of polarization P-r with respect to applied pressure and the Landau-Devonshire (LD) phenomenological approach. The results showed that hydrostatic pressure can induce ferroelectric-to-paraelectric phase transition, while 1D compression can stablize the ferroelectric phase. This phenomenon was very different from the phase transitions of metal crystals, such as iron. In the framework of LD phenomenological theory, this phenomenon is believed to be associated with the strong anisotropy and electromechanical coupling which exists in ferroelectrics under high pressure. On the other hand, the piezoelectric stress coefficient e(31) and piezoelectric strain coefficient d(h) for PIN-PMN-PT crystal were obtained as -2.9 C m(-2) and 80 pC N-1, respectively.