Dielectric functions and phase transitions of MgO modified Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 ceramics revealed by spectroscopic ellipsometry
Abstract The dielectric functions and phase transitions of MgO modified Pb 0.99 (Zr 0.95 Ti 0.05 ) 0.98 Nb 0.02 O 3 (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  ∼ 250 K), low temperature ferroelectric phase [FE R(LT) ]to high temperature one [FE R(HT) ] (T 2  ∼ 300 K), and ferroelectric-paraelectric phase (T C  ∼ 500 K).