Unveiling Unconventional Ferroelectric Switching in Multiferroic Ga0.6 Fe1.4O3 Thin Films Through Multiscale Electron Microscopy Investigations

TL;DR

This study reveals an unconventional ferroelectric switching mechanism in Ga0.6Fe1.4O3 thin films, confirmed through multiscale electron microscopy, highlighting cationic mobility and local domain wall motion as key factors.

Contribution

It provides experimental evidence for a non-traditional ferroelectric switching mechanism in Ga0.6Fe1.4O3, challenging conventional energy-demanding models.

Findings

Confirmation of cationic mobility in atomic positions.

Direct observation of cationic displacements.

Unconventional switching via local domain wall motion.

Abstract

Understanding the polarization switching mechanisms at play in ferroelectric materials is crucial for their exploitation in electronic devices. The conventional centrosymmetric reference structure-based mechanism which accounts for ferroelectricity in most of the usual displacive ferroelectric materials is too energy-demanding for some newly diagnosed ferroelectric materials such as the Ga2-xFexO3 (0.8 < x < 1.4) compounds. Some alternative theoretical propositions have been made and need experimental confirmation. A dual-scale electron microscopy study is performed on thin films of the Ga0.6Fe1.4O3 multiferroic compound. A wide scale precession-assisted electron diffraction tomography study first allows the determination of the structure the compound adopts in thin films, and even permits the refinement of the atomic positions within this structure. Cationic mobility is suggested for two of the atomic positions through the existence of extra electronic density. A local in situ high resolution scanning transmission electron microscopy study then allows confirming these mobilities by directly spotting the cationic displacements on successively acquired images. The whole study confirms an unconventional switching mechanism via local domain wall motion in this compound.