Nano-scale oxygen octahedral tilting in 0.90(Bi1/2Na1/2)TiO3-0.05(Bi1/2K1/2)TiO3-0.05BaTiO3 lead-free perovskite piezoelectric ceramics

TL;DR

This study investigates nano-scale oxygen octahedral tilting in a lead-free perovskite ceramic using TEM, revealing mixed tilted domains with sizes from 1 to 8 nm and their distribution.

Contribution

It provides detailed TEM analysis of octahedral tilt domains in a specific lead-free piezoelectric ceramic, highlighting nano-scale domain structures.

Findings

Presence of antiphase and in-phase tilted domains

Domains vary from 1 to 8 nm in size

Mixture of non-tilted and tilted domains

Abstract

The oxygen octahedral tilted domains in 0.90(Bi1/2Na1/2)TiO3-0.5(Bi1/2K1/2)TiO3-0.5BaTiO3 lead-free perovskite piezoelectric ceramic have been studied by transmission electron microscopy (TEM). Selected-area electron diffraction patterns shows the 1/2ooo and 1/2ooe reflections, indicating the presence of antiphase (a-a-a-) and in-phase (aoaoc+) octahedral tilting, respectively. The morphology and distributions of these tilted domains are shown in the centered dark-field images. Further, the Bragg-filtered high-resolution TEM image reveals that the size of the in-phase tilted domains varies from 1 to 8 nm across. The ceramic contains the mixture of non-tilted and variants of the antiphase and in-phase tilted domains.