Temperature-Pressure Phase Diagram Of Relaxor Ferroelectric Pb(Mg1/3nb2/3)O-3

The effects of hydrostatic pressure of up to 2.7 GPa on the dielectric constant and pyroelectric charge of Pb(Mg1/3Nb2/3)O-3 single crystal were investigated. In addition to the broad and frequency-dependent dielectric anomaly of the relaxor state, a distinct secondary dielectric anomaly was found at pressures higher than approximately 0.7 GPa. This new dielectric anomaly was confirmed consistently by isothermal and isobaric measurements. The pressure dependences of the peak temperature of the dielectric constant, the freezing temperature, and the temperature at which the secondary dielectric anomaly disappeared (T-a) were investigated. The Ta line in the temperature-pressure phase diagram represents the phase boundary of the pressure-induced structural phase transition.