Reversible long-range domain wall motion in an improper ferroelectric

TL;DR

This study reveals that improper ferroelectric ErMnO3 exhibits reversible long-range domain wall motion exceeding 250 nm, driven by intrinsic properties linked to topological vortex lines, which is promising for device applications.

Contribution

It demonstrates that long-range reversible domain wall motion occurs naturally in ErMnO3, a finding that challenges previous limitations and links the behavior to the material's improper ferroelectricity and topological features.

Findings

Domain walls can move over 250 nm and return to initial positions.

Reversible motion is intrinsic to hexagonal manganites due to topological vortex lines.

Local switching behavior was characterized with nanometric precision.

Abstract

Reversible ferroelectric domain wall movements beyond the 10 nm range associated with Rayleigh behavior are usually restricted to specific defect-engineered systems. Here, we demonstrate that such long-range movements naturally occur in the improper ferroelectric ErMnO3 during electric-field-cycling. We study the electric-field-driven motion of domain walls, showing that they readily return to their initial position after having travelled distances exceeding 250 nm. By applying switching spectroscopy band-excitation piezoresponse force microscopy, we track the domain wall movement with nanometric spatial precision and analyze the local switching behavior. Phase field simulations show that the reversible long-range motion is intrinsic to the hexagonal manganites, linking it to their improper ferroelectricity and topologically protected structural vortex lines, which serve as anchor point for the ferroelectric domain walls. Our results give new insight into the local dynamics of domain walls in improper ferroelectrics and demonstrate the possibility to reversibly displace domain walls over much larger distances than commonly expected for ferroelectric systems in their pristine state, ensuring predictable device behavior for applications such as tunable capacitors or sensors