The Intrinsic Structural Resistance of a Grain Boundary to Transverse Ionic Conduction

Invited for this month's cover picture is the group of Prof. Roger A. De Souza at RWTH Aachen University (Germany). The cover picture illustrates oxide ions moving from one crystal grain across a grain boundary to an adjacent grain in a polycrystalline oxide‐ion conductor. The mobile ions perceive the boundary as an additional resistance arising from the disruption of the crystal structure at the boundary. The resistance can be tuned by applying high electric fields. Read the full text of the Communication at 10.1002/celc.202000773. “A new procedure is presented for determining the structural resistance of a grain boundary. The resistance is compared with space‐charge resistances arising from depleted charge carriers at the boundary. Contrary to common belief, the structural resistance is not negligible under all circumstances but becomes comparable to the space‐charge resistance at elevated temperatures, calling for a systematic exploration….“ Learn more about the story behind the research featured on the front cover in this issue's Cover Profile. Read the corresponding Communication at 10.1002/celc.202000773.