TY - JOUR
T1 - Controlled Nucleation and Stabilization of Ferroelectric Domain Wall Patterns in Epitaxial (110) Bismuth Ferrite Heterostructures
AU - Zhang, Yangyang
AU - Tan, Yueze
AU - Sando, Daniel
AU - Chen, Long Qing
AU - Valanoor, Nagarajan
AU - Zhu, Yimei
AU - Han, Myung Geun
N1 - Funding Information:
Y.‐Y.Z. and Y.T. contributed equally to this work. This work was supported by the U.S. DOE Basic Energy Sciences, Materials Sciences, and Engineering Division under Contract No. DESC0012704. N.V., D.S., and Y.‐Y.Z, acknowledge the support of the ARC Discovery Project program. This research was partially supported by the Australian Research Council Centre of Excellence in Future Low‐Energy Electronics Technologies (Project No. CE170100039), and the Australian Research Council (ARC) through the funding of Discovery Grants and funded by the Australian Government. The work at Pennsylvania State University was supported by the Penn State MRSEC, Center for Nanoscale Science, under the award NSF DMR‐1420620 (Y.T.) and DMR‐1744213. TEM sample preparation by FIB was performed at the Center for Functional Nanomaterials, Brookhaven National Laboratory. The custom‐made code used for displacement mapping was developed by Lijun Wu, Brookhaven National Laboratory.
PY - 2020/11/25
Y1 - 2020/11/25
N2 - Ferroelectric domain walls, topological entities separating domains of uniform polarization, are promising candidates as active elements for nanoscale memories. In such applications, controlled nucleation and stabilization of domain walls are critical. Here, using in situ transmission electron microscopy and phase-field simulations, a controlled nucleation of vertically oriented 109° domain walls in (110)-oriented BiFeO3 (BFO) thin films is reported. In the switching experiment, reversed domains that are nucleated preferentially at the nanoscale edges of the “crest and sag” pattern-like electrode under external bias subsequently grow into a stable stripe configuration. In addition, when triangular pockets (with an in-plane polarization component) are present, these domain walls are pinned to form stable flux-closure domains. Phase field simulations show that i) field enhancement at the edges of the electrode causes site-specific domain nucleation, and ii) the local electrostatics at the domain walls drives the formation of flux closure domains, thus stabilizing the striped pattern, irrespective of the initial configuration. The results demonstrate how flux closure pinning can be exploited in conjunction with electrode patterning and substrate orientation to achieve a desired topological defect configuration. These insights constitute critical advancements in exploiting domain walls in next generation ferroelectronic devices.
AB - Ferroelectric domain walls, topological entities separating domains of uniform polarization, are promising candidates as active elements for nanoscale memories. In such applications, controlled nucleation and stabilization of domain walls are critical. Here, using in situ transmission electron microscopy and phase-field simulations, a controlled nucleation of vertically oriented 109° domain walls in (110)-oriented BiFeO3 (BFO) thin films is reported. In the switching experiment, reversed domains that are nucleated preferentially at the nanoscale edges of the “crest and sag” pattern-like electrode under external bias subsequently grow into a stable stripe configuration. In addition, when triangular pockets (with an in-plane polarization component) are present, these domain walls are pinned to form stable flux-closure domains. Phase field simulations show that i) field enhancement at the edges of the electrode causes site-specific domain nucleation, and ii) the local electrostatics at the domain walls drives the formation of flux closure domains, thus stabilizing the striped pattern, irrespective of the initial configuration. The results demonstrate how flux closure pinning can be exploited in conjunction with electrode patterning and substrate orientation to achieve a desired topological defect configuration. These insights constitute critical advancements in exploiting domain walls in next generation ferroelectronic devices.
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U2 - 10.1002/adfm.202003571
DO - 10.1002/adfm.202003571
M3 - Article
AN - SCOPUS:85090957793
VL - 30
JO - Advanced Functional Materials
JF - Advanced Functional Materials
SN - 1616-301X
IS - 48
M1 - 2003571
ER -