Study on the dielectric properties of 0.75Pb(Mg_1/3Nb _2/3)O_3-0.25PbTiO₃ ceramic under hydrostatic pressure

The dielectric properties of 0.75Pb(Mg1/3Nb2/3)O₃-0.25PbTiO 3 (PMN-25PT) ceramic under hydrostatic pressure and pressure-induced phase transition were investigated. PMN-25PT ceramic is pure perovskite with weak relaxation at 1 bar. With increasing hydrostatic pressure, the temperature, T_m, of top dielectric constant decreases, dT_m/dP ≈-4°/kbar, frequency dispersion and phase transition diffuse increases, remnant polarization decreases continuously. The hydrostatic pressure dependence of dielectric constant (ε′) is similar to the temperature dependence of dielectric constant. The relax ferroelectric-paraelectric (RFE-PE) phase transition was induced by hydrostatic pressure and the transition was gradual change process with stronger relaxor behavior than by temperature-induced.