Structural complexity of ( Na 0.5 Bi 0.5 ) TiO 3 -BaTiO 3 as revealed by Raman spectroscopy
Year: 2010
Type: article
Abstract: The structural phase diagram of the Pb-free ferroelectric ${({\text{Na}}_{1/2}{\text{Bi}}_{1/2})}_{1\ensuremath{-}x}{\text{Ba}}_{x}{\text{TiO}}_{3}$, $x<0.1$, has been explored by Raman spectroscopy at temperatures from 10 to 470 K. The data provide clear evidence for a proposed temperature-independent morphotropic phase boundary at $x\ensuremath{\approx}0.055$. However, there is no evidence for a structural phase transition across $T\ensuremath{\approx}370\text{ }\text{K}$ for $x>0.055$, where bulk-property anomalies appear to signal a transition to a nonpolar or antiferroelectric phase. The results identify that the phase above 370 K shows short-range ionic displacements that are identical to those in the long-range-ordered phase below 370 K. These conclusions provide a natural interpretation of the weak piezoelectric response in this system and have important implications for the search for Pb-free piezoelectrics.
Source: Physical Review B
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1510855962