Temperature-electric-field phase diagram for Pb(Zn 1/3 Nb 2/3 )O 3 -PbTiO 3 - concentration dependence of the critical endpoint -

The temperature and the DC biasing-field dependences of the dielectric permittivities along the [001] c , [011] c , and [111] c directions of the pseudocubic coordinates have been investigated in Pb(Zn 1/3 Nb 2/3 )O 3- x PbTiO 3 ( x = 6%). The temperature-electric-field phase diagrams have been clarified in the field range below 8 kV/cm. The critical endpoint has been found at 1.3 kV/cm and 164°C for an electric field applied along the [001] c direction. The concentration dependences of the critical temperature and the transition temperature are discussed. The expected transition temperature T 0 ( x ) at which the second-order phase transition would occur is shown to be determined by the transition temperature T CT ( x ) and the critical temperature T CEP ( x ).