弛豫型铁电体的动态相变行为研究

Dynamic Phase Transition in Relaxor Ferroelectrics

通过对掺钛铌镁酸铅铁电陶瓷Ｐｂ（Ｍｇ１／３Ｎｂ２／３）０．８Ｔｉ０．２Ｏ３介电、铁电、热学行为及结构等的详细测量，发现这一材料由高温顺电态转变为弛豫型铁电态，表现出典型弥散性相变特征；由弛豫型铁电态转变为正常铁电态，则表现出一级相变特征。进而探讨了复合钙钛矿铁电体中极性微区的动态结构转变特征。

Dielectric,ferroelectric and thermal behaviors of Pb(Mg1/3Nb2/3)0.8Ti0.2O3(designated as PMNT80/20)ferroelectric ceramics have been carefully measured as a function of temperature.Two phase transitions can be seen clearly.One is the diffused phase transition near the temperature of the dielectric permittivity maxima(Tm).The another is a spontaneous relaxornormal ferroelectric phase transition.These phase transitions have been discussed using dynamic behavior of polar microregion.