MSE 298 Seminar Lecture (Zoom): Harnessing Disorder In Metal Oxides - Making Gibbs and Boltzmann Proud

Zoom: Meeting ID 995 8022 3426, Password 587901

Abstract: Lattice defects play an important role in the dielectric and conductivity properties of ceramic materials, and thus great effort is expended on controlling point defect concentrations via doping, oxygen-activity and temperature control during processing. In device applications, because lattice defects are typically charged, applied electric fields provide a strong driving force for defect migration, and their spatio-temporal redistribution depends on numerous experimental variables including the interfacial boundary conditions. Ultimately the defect redistribution process leads to spatially varying conductivity profiles and often a concomitant macroscopic increase in leakage current in many dielectric materials. While this leakage current enhancement is detrimental in devices such as capacitors, the phenomenon can be utilized to form novel functional behaviors such as resistive switching in metal-oxides. Furthermore, the use of electric fields in processing ceramic materials, e.g. flash sintering, can lead to analogous electromigration processes resulting in long-range chemical and microstructural gradients. This talk will review our current understanding and implications of point defect electromigration in important electroceramic materials.

Bio: Elizabeth Dickey is a Distinguished Professor and associate head of the Department of Materials Science and Engineering at North Carolina State University. A primary focus of her research aims to develop processing-structure-property relationships for materials in which the macroscopic physical properties are governed by point defects, grain boundaries or internal interfaces. She has more than 150 peer-reviewed journal publications in these areas, which have been cited over twenty-thousand times. Dickey is a fellow of the American Ceramic Society and the Microscopy Society of America. She is currently an editor of the Journal of the American Ceramic Society and editor-in-chief of Cambridge University Press’ Elements in Microscopy and Microanalysis. She is president-elect of the American Ceramic Society, and in January 2021, she will move to Carnegie Mellon University where she will become the head of the Department of Materials Science and Engineering.