Precise determination of phonon constants in lead-free monoclinic (K 0.5Na0.5)NbO3 single crystals

Abstract

A polarized Raman analysis of ferroelectric (K0.5Na 0.5)NbO3 (KNN) single crystals is presented. The Raman modes of KNN single crystals are assigned to the monoclinic symmetry. Angular-dependent intensities of A′, A″, and mixed A′ A″ phonons have been theoretically calculated and compared with the experimental data, allowing the precise determination of the Raman tensor coefficients for (non-leaking) modes in single-domain monoclinic KNN. This study is the basis for non-destructive assessments of domain distribution by Raman spectroscopy in KNN-based lead-free ferroelectrics. © 2014 © 2013 Author(s).