Phase structure and electrical properties of 0.8Pb(Mg_(1/3)Nb_(2/3))O_3-0.2PbTiO_3 relaxor ferroelectric ceramics prepared by the reaction-sintering method

摘要

Phase pure perovskite 0.8Pb(Mg_(1/3)Nb_(2/3))O_3-0.2PbTiO_3 (0.8PMN-0.2PT) ferroelectric (FE) ceramics were prepared by the reaction-sintering method at a sintering temperature range of 1200-1250 ℃. The sintered ceramics exhibit large relative density, where the 0.8PMN-0.2PT ceramics sintered at 1250 ℃ possess the largest value of relative density, reaching 99.56% of the theoretical density. All the sintered 0.8PMN-rn0.2PT ceramics exhibit broad, diffused, and frequency-dependent dielectric response peaks at around 80 ℃ and saturated and symmetric P-E hysteresis loops. The 0.8PMN-0.2PT ceramics exhibit excellent electrical properties, where the value of dielectric constant maximum ε_m is 35 750 at 1 kHz, the remanent polarization P_r is 33.01 μC/cm~2, the coercive field E_c is 2.79 kV/ cm, and the piezoelectric constant d_(33) is 259 pC/N.