Influence of nanoscale regions on Raman spectra of complex perovskites

TL;DR

This paper introduces a phonon-confinement model-based method for interpreting Raman spectra of complex perovskites, demonstrating its accuracy and revealing nanoscale region sizes as intrinsic, temperature-independent features.

Contribution

The study presents a new approach using the phonon-confinement model to analyze Raman spectra of complex perovskites, validated by experimental and simulated data.

Findings

Nanoscale regions are intrinsic and temperature-independent.

The method accurately describes Raman spectra of specific perovskites.

Two temperature points (~400 K and 600 K) affect mode parameters.

Abstract

New approach on interpretation and processing of Raman spectra of complex perovskites is suggested. Raman spectra of $PbMg_{1/3}Nb_{2/3}O_{3}$ and $% PbSc_{1/2}Ta_{1/2}O_{3}$ are successfully described on the basis of the phonon-confinement model and validity of the method is demonstrated on good agreement of experimentally obtained and computer simulated spectra of another complex perovskite, $BaMg_{1/3}Ta_{2/3}O_{3}$. The study showed that the size of nanoscale regions is a kind of an inborn characteristic of the sample and is not temperature dependent. For $PbSc_{1/2}Ta_{1/2}O_{3}$, two special temperature points, approximately 400 K and 600 K are found from the analysis of the temperature behaviour of obtained mode parameters.