Pb(Zr,Sn,Ti)O3反铁电陶瓷的低温相变扩散与极化弛豫

用弱场介电温谱、热释电流谱、强场电滞回线和变温X射线衍射谱研究了微量La掺杂Pb(Zr,Sn,Ti)O₃(PZST)反铁电(AFEt)陶瓷在-100—180℃温区内的结构与电学特性.弱场介电温谱显示，AFEt陶瓷在低温段(-100—50℃)呈现介电频率弥散(0.1—100kHz)和扩散型相变的特征，而变温X射线衍射谱却表明材料在这一温区内保持四方相结构；低温下经强场作用后，AFEt被诱导为亚稳三方铁电态，介电频率弥散消失.基于多元复杂化合物的组分起伏理论，讨论了PZST AFEt陶瓷 关键词： Pb(Zr Sn 3反铁电陶瓷')" href="#">Ti)O₃反铁电陶瓷 反铁电弛豫 相变 变温X射线衍射

INVESTIGATION OF DIFFUSED PHASE TRANSITION AND POLAR RELAXATION IN Pb(Zr,Sn,Ti)O3 ANTIFERROELECTRIC CERAMICS

Microstructure and electrical properties of lanthanum-modified Pb(Zr,Sn,Ti)O₃(PZST) antiferroelectric (AFE) ceramics have been investigated by weak field dielectric, pyroelectric response, strong field polarization, and X-ray diffraction (XRD) techniques at different temperatures. Diffused phase transition and dielectric frequency dispersion (0.1—100kHz) have been observed within the temperature range of -100—50℃. However, XRD indicates that AFE ceramics are of tetragonal phase within the above-mentioned temperature range. Under a strong electric field, AFEt will be switched to a metastable ferroelectric (MFE) state, accompanying with the disappearance of dielectric frequency dispersion. Then the MFE state changes to AFE state again as temperature increases, producing a strong pyroelectric current peak. A new model considering compositional fluctuation on a nanometer scale in PZST antiferroelectric ceramics has been suggested to explain the polar relaxation in AFE state.