Dielectric functions and phase transitions of MgO modified Pb_(0.99)(Zr_(0.95)Ti_(0.05))_(0.98)Nb_(0.02)O_3 ceramics revealed by spectroscopic ellipsometry

摘要

The dielectric functions and phase transitions of MgO modified Pb-0.99(Zr0.95Ti0.05)(0.98)Nb0.02O3 (PZTN-x wt% MgO, x = 0, 0.1, 0.2, 0.5) ceramics have been investigated using temperature-dependent spectroscopic ellipsometry. With the aid of standard critical-point (SCP) model, four typical interband transitions can be observed from the second derivative of dielectric functions. Three transition process are observed and can be linked to antiferroelectric (AFE)-ferroelectric (FE) (T-1 similar to 250 K), low temperature ferroelectric phase [FER(LT)] to high temperature one [FER(HT)] (T-2 similar to 300 K), and ferroelectric-paraelectric phase (T-C similar to 500 K). (C) 2019 Elsevier B.V. All rights reserved.