The A-site driven phase transition procedure of (Pb0.97La0.02)(Zr0.42Sn0.40Ti0.18)O3 ceramics: An evidence from electronic structure variation

摘要

The transition of (Pb0.97La0.02)(Zr0.42Sn0.40Ti0.18)O3 (PLZST) ceramic has been investigated by temperature-dependent X-ray diffraction (XRD) and spectroscopic ellipsometry (SE). The rhombohedral and tetragonal symmetries are confirmed by XRD analysis. Two interband transitions (Ecp1 and Ecp2) located at about 3.7 and 5.2 eV can be derived from the second derivative of the complex dielectric functions using the standard critical point (SCP) model. Except for the negative temperature coefficient parts, the transitions present additional parts corresponding to appearance of the antiferroelectric (AFE) phase. The phenomena can be attributed to variation of the electronic structure during A-site driven phase transition.