组份变化对{ PZST陶瓷反铁电-铁电相变的影响

摘要

Phase structures，properties and critical parameters of field-induced phase transitions of PZST ceramics near ferroelectric(FE)-antiferroelectric(AFE) phase boundary were studied as a function of composition and temperature．The electric field-induced FE state can maintain metastable state below the critical temperature TFE-AFE after electric field is removed．As temperature increases，the metastable FE state changes to AFE state at TFE-AFE．As Ti content increases，the structure of unpoled PZST ceramics changes from tetragonal AFE phase to rhombohedral FE phase，dielectric constant maximum max and transition temperature TFE-AFE increase，switching field EAFE-FE and EFE-AFE decrease．The forward switching field EAFE-FE and hysteresis E were observed to be dependent on TFE-AFE and Tc，respectively，and EAFE-FE and E decreased with an associated increasing in TFE-AFE and decreasing in Tc．%对FE-AFE相界附近PZST陶瓷结构、性能及场诱相变临界参数随组份和温度的变化进行了研究.在相变临界温度TFE-AFE以下，被电场诱导出的铁电态在撤去电场后以亚稳态形式存在，随着温度升高，亚稳铁电态在此温度转变为反铁电态.随着Ti含量的增加，样品由四方反铁电相穿越相界转变为三方铁电相，介电常数峰值max增大；同时亚稳铁电态反铁电态相变温度TFE-AFE上升，电场诱导的AFE相变临界参数EAFE-FE、EFE-AFE减小.实验中发现EAFE-FE和 E分别与TFE-AFE和Tc相关，随着TEF-AFE的升高和Tc的降低，EAEF-FE和 E相应减小.