MSE Seminar: Point Defect Engineering in Metal Oxides
Speaker: Elizabeth C. Dickey, Professor & Unit Head, Materials Science & Engineering, Carnegie Mellon University
Title: Point Defect Engineering in Metal Oxides
Lattice defects play an important role in the dielectric and conductivity properties of electroceramic 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. This talk will review our current understanding and implications of point defect electromigration in important electroceramic materials. Recent efforts to effectively co-dope dielectric materials to improve their degradation resistance will be discussed.
Elizabeth Dickey is the Teddy & Wilton Hawkins Distinguished Professor and Head of the Department of Materials Science and Engineering at Carnegie Mellon 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 over 150 peer-reviewed journal publications in these areas, which have been cited over twenty-thousand times. Professor Dickey is a fellow of the American Ceramic Society, Microscopy Society of America, and AAAS. 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. Professor Dickey is president-elect of the American Ceramic Society.