Nanoscale bubble domains with polar topologies in bulk ferroelectrics

Jie Yin,Haijun Wu,Jianguo Zhu,Li-Dong Zhao,Hongxiang Zong,Jun Sun,Xiangdong Ding,Yang Zhang,Hong Tao,Xuefei Tao,Jiagang Wu,Stephen J Pennycook

doi:10.1038/s41467-021-23863-w

Abstract

Multitudinous topological configurations spawn oases of many physical properties and phenomena in condensed-matter physics. Nano-sized ferroelectric bubble domains with various polar topologies (e.g., vortices, skyrmions) achieved in ferroelectric films present great potential for valuable physical properties. However, experimentally manipulating bubble domains has remained elusive especially in the bulk form. Here, in any bulk material, we achieve self-confined bubble domains with multiple polar topologies in bulk Bi0.5Na0.5TiO3 ferroelectrics, especially skyrmions, as validated by direct Z-contrast imaging. This phenomenon is driven by the interplay of bulk, elastic and electrostatic energies of coexisting modulated phases with strong and weak spontaneous polarizations. We demonstrate reversable and tip-voltage magnitude/time-dependent donut-like domain morphology evolution towards continuously and reversibly modulated high-density nonvolatile ferroelectric memories.

Highlights

Multitudinous topological configurations spawn oases of many physical properties and phenomena in condensed-matter physics
Determined by a critical balance among elastic, electrostatic, and gradient energy terms, bubble domains might be stable only within a very narrow range of boundary conditions. It leads to the long-standing challenge of capturing such special domain structure in relaxor ferroelectrics[2,3,4,5,19], especially for bulk ferroelectrics that lack the epitaxial constraint of multilayer thin films
Do we demonstrate the possibility of triggering the bubble domains in bulk ferroelectrics, and our results demonstrate that Bi0.5Na0.5TiO3-based relaxor ferroelectrics represent a material family exhibiting polar skyrmions

Summary

Introduction

Multitudinous topological configurations spawn oases of many physical properties and phenomena in condensed-matter physics. The total free energy of bulk ferroelectrics is mainly affected by the competition of bulk, elastic, and electrostatic energy terms of coexisting modulated phases, which determines the observed bubble domains, especially for vortices or skyrmions.

Results

Conclusion