Electrical and Structural Characterization of a Low‐Angle Tilt Grain Boundary in Iron‐Doped Strontium Titanate

Abstract

The atomistic structure and electrical properties of a symmetrical 5.4° [001] tilt grain boundary in Fe‐doped SrTiO3 have been investigated, respectively, by means of various transmission electron microscopy (TEM) techniques and impedance spectroscopy. In weak‐beam dark‐field images, the grain boundary is revealed to consist of a periodic array of dislocations; high‐resolution TEM images show that the dislocation cores are separated by regions of strained lattice. The impedance response of the bicrystal has been measured in the frequency range 20 Hz ≤f≤ 106 Hz as a function of temperature and oxygen partial pressure. The transport of charge across the array of dislocations that form the grain boundary is strongly hindered. Analysis of the impedance data in terms of a double‐Schottky‐barrier model yields a space‐charge potential that exhibits a weak dependence on temperature and oxygen partial pressure and is ∼0.55 V in the investigated regime.

When two become one: An insight into 2D conductive oxide interfaces

“…These factors usually lead to remarkable formation of electronic defects, which overlapped the existing ionic conductivity, increase the total conduction even in dominantly ionically conducting or dielectric materials. Effects of interfacial conductivity enhancement in a few orders of magnitude due to electronic contribution were thus observed in nanometric polycrystalline metals oxides such as Y-doped ZrO2, CeO2 [61,73], Fe-doped SrTiO3 [85], NiO, ZnO, Al2O3, MgO [86][87][88][89]. Similar effects are registered also in hetero-interfaces (as in Fig.…”

Dislocations in plastically deformed SrTiO3

“…Using electron energy-loss spectroscopy, for all dislocations an increase of the Ti-to-O ratio was found in the core region suggesting a charged core. For the a<110>{110} edge dislocation the presence of charge was indeed confirmed by impedance spectroscopy measurements on the same bi-crystals [8].…”

Oxygen Reduction at Dense Thin-Film Microelectrodes on a Proton-Conducting Electrolyte

“…case (iii). 51,52 One the other hand, an example for different majority carriers in the surface layer as a consequence of changed charge state is nominally undoped CeO 2 at comparably low temperatures. 53 Here V…”