Characterization of ferroelectric domain walls by scanning electron microscopy

Abstract

Paper published as part of the special topic on Domains and Domain Walls in Ferroic Materials DDWFM2021 This paper was selected as an Editor's Pick ARTICLES YOU MAY BE INTERESTED IN Contributions to polarization and polarization switching in antiphase boundaries of SrTiO 3 and PbZrO 3

Contact-free reversible switching of improper ferroelectric domains by electron and ion irradiation

“…See, e.g., ref. 34 for a more detailed discussion of SEM domain and domain wall contrast in ferroelectrics.…”

Imaging Ferroelectric Nanodomains in Strained BiFeO3 Nanoscale Films Using Scanning Low-Energy Electron Microscopy: Implications for Low-Power Devices

“…Among the multiferroic nanomaterials, the lead-free multiferroic BiFeO 3 is currently one of the very few exhibiting ferroelectric and antiferromagnetic ordering above room temperature, thus it has been intensively investigated over the last two decades . Domain walls in multiferroic BiFeO 3 nanoscale films exhibit plenty of novel properties, including enhanced conductivity, photovoltages, and current rectification . Using a combination of strain engineering in conjunction with chemical doping will trigger a nanostructural transition from the rhombohedral-like ( R ) ground state to the so-called tetragonal-like ( T ) phase in the polymorph .…”

“…Thus, irradiation with charged particles can generate a significant surface charge, which can cause distortions and imaging artifacts. The ratio between emitted electrons and incident electron is highly material dependent and varies with the electron-beam voltage . Given that, a more recently introduced technique for studying ferroelectric nanodomains is LEEM, it can realize noncontact low-energy imaging, providing less invasive and more panoramic view of ferroelectric nanodomains. − From a technical point of view, this technique opportunely complements two of the main characterization methods for ferroelectric nanodomains, namely, PFM and TEM.…”

“…Given that, a more recently introduced technique for studying ferroelectric nanodomains is LEEM, it can realize noncontact low-energy imaging, providing less invasive and more panoramic view of ferroelectric nanodomains. − From a technical point of view, this technique opportunely complements two of the main characterization methods for ferroelectric nanodomains, namely, PFM and TEM. It is very well known that applying a negative potential to the sample reduces beam-landing energies and, thereby, reduces beam damage to the sample and improves the contrast and resolution of the images. , However, accumulation of results obtained when applying the LEEM method to various families of samples from the material science and technology branches may seem slower than expected, likely because of the lack of comprehensive guides to interpretation of micrographs and its underlying polarization contrast mechanism. , Consequently, there have been limited studies of ferroelectric nanodomain visualization via LEEM and, specifically, its relevance to imaging ferroelectric nanodomains in BiFeO 3 nanoscale films. ,− …”

The third dimension of ferroelectric domain walls

“…Thus, their intrinsic electronic transport properties are difficult to access. The conduction of ferroelectric domain walls at surfaces and in near-surface regions has been analyzed by different scanning probe [14][15][16][17] and electron microscopy techniques [18][19][20][21][22][23] and the 3D behavior has been concluded from scans obtained on different surfaces. To resolve the currents that are going through individual ferroelectric domain walls, top and bottom electrodes have been applied to thin films [14,24,25], single-crystals [10,26,27] and FIB-cut lamellas [28].…”