Shear strain-induced anisotropic domain evolution in mixed-phase BiFeO3 epitaxial films

Han Xu,Zuhuang Chen,Haidan Wen,Xiaoyi Zhang,Zhenlin Luo,Changgan Zeng,Jiangtao Zhao,Sujit Das,Yongqi Dong,Bin Hong,Chen Gao,Lang Chen

doi:10.1063/1.5080709

Abstract

Understanding and controlling the domain evolution under external stimuli in multiferroic thin films is critical to realizing nanoelectronic devices, including for non-volatile memory, data storage, sensors, and optoelectronics. In this article, we studied the shear-strain effect on the domain evolution with temperature in highly strained BiFeO3 thin films on rhombohedral LaAlO3 substrates using a high-resolution synchrotron X-ray diffraction three dimensional-reciprocal space mapping (3D-RSM) technique. The results revealed significant biaxial, anisotropic, evolution behaviors of the mixed-phase (MC + R′/T′ phases) BiFeO3 ferroelectric domains along the in-plane [100] and [010] axes. These biaxial, anisotropic, evolution behaviors were attributed to the shear-strain-modulated transition pathways of the mixed-phase ferroelectric domains. This viewpoint was further verified in the BiFeO3/LaSrAlO4 (001) system in which no anisotropic evolution behaviors of the mixed-phase domains were found. This work sheds light on the quantitative analysis of domain evolution in multi-domain systems and demonstrates that the shear-strain effect could act as an effective tool to manipulate the domain behavior and control novel functionalities of ferroelectric thin films.

Highlights

Ferroelectric thin films usually form domains that minimize the total free energy of the system
Our study demonstrates that by taking the intrinsic crystal symmetry of a substrate as the variable, ferroelectric domains could be engineered to reveal the anisotropic domain evolution process through modulation of the in-plane interfacial shear-strain
Our quantitative synchrotron X-ray diffraction 3D-RSM results reveal that the domain volume, domain tilt angle, and interfacial strain at the domain wall of the mixed-phase (MC + R /T phases) BiFeO3 films exhibit biaxial anisotropic evolutionary behavior

Summary

Introduction

Ferroelectric thin films usually form domains that minimize the total free energy of the system. The domain evolution with external stimuli (e.g., thermal, electric field, strain) has a profound impact on the dielectric permittivity, piezoelectric response, and polarization switching behavior.. Recent studies have shown that domain walls themselves can possess additional functionalities (e.g., electric conductivity and enhanced magnetization4) and have the potential to exhibit other interesting effects.. It is important to deterministically control the domain evolution with external stimuli in ferroelectric thin films. BiFeO3 has been extensively studied because of its room temperature multiferroicity with potential applications in nanoelectronic and spintronic devices.. Detailed studies have reported that large compressive strains can induce a morphotropic phase boundary (MPB)-like behavior and create large piezoelectric responses in BiFeO3 films.. BiFeO3 has been extensively studied because of its room temperature multiferroicity with potential applications in nanoelectronic and spintronic devices. Detailed studies have reported that large compressive strains can induce a morphotropic phase boundary (MPB)-like behavior and create large piezoelectric responses in BiFeO3 films. Multiple low-symmetry phases, including monoclinic MC, MA, and two tilted triclinic (R and T ) phases have been revealed in BiFeO3 films grown on LaAlO3 (001) substrates.

Methods

Results

Conclusion