Deterministic Ferroelastic Domain Switching Using Ferroelectric Bilayers

Zhang, Yangyang; Han, Myung-Geun; Garlow, Joseph A.; Tan, Yueze; Xue, Fei; Chen, Long-Qing; Munroe, Paul; Valanoor, Nagarajan; Zhu, Yimei

doi:10.1021/acs.nanolett.9b01782

Title: Deterministic Ferroelastic Domain Switching Using Ferroelectric Bilayers

Journal Article · Wed Jul 03 00:00:00 EDT 2019 · Nano Letters

DOI:https://doi.org/10.1021/acs.nanolett.9b01782· OSTI ID:1566820

Zhang, Yangyang ^[1];

^[2]; Garlow, Joseph A. ^[2]; Tan, Yueze ^[3]; Xue, Fei ^[3]; Chen, Long-Qing ^[3]; Munroe, Paul ^[4];

^[4];

^[2]

Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.; Univ. of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering
Brookhaven National Lab. (BNL), Upton, NY (United States). Condensed Matter Physics and Materials Science Dept.
Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
Univ. of New South Wales, Sydney, NSW (Australia). School of Materials Science and Engineering

Composition gradients, or dissimilar ferroelectric bilayers, demonstrate colossal electromechanical figures of merit attributed to the motion of ferroelastic domain walls. Yet, mechanistic understanding of polarization switching pathways that drive ferroelastic switching in these systems remains elusive. Here, the crucial roles of strain and electrostatic boundary conditions in ferroelectric bilayer systems are revealed, which underpin their ferroelastic switching dynamics. Using in situ electrical biasing in the transmission electron microscope (TEM), the motion of ferroelastic domain walls is investigated in a tetragonal (T) Pb(Zr,Ti)O₃ (PZT)/rhombohedral (R) PZT epitaxial bilayer system. Atomic resolution electron microscopy, in tandem with phase field simulations, indicates that ferroelastic switching is triggered by predominant nucleation at the triple domain junctions located at the interface between the T/R layers. Furthermore, this interfacial nucleation leads to systematic reversable reorientation of ferroelastic domain walls. Finally, deterministic ferroelastic domain switching, driven by the interfacial strain and electrostatic boundary conditions in the ferroelectric bilayer, provides a viable pathway toward novel design of miniaturized energy-efficient electromechanical devices.

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