Seminar: Defect Chemistry of Metal Oxides
Presented by Dr Nitish Kumar, from the School of Materials Science and Engineering at UNSW Sydney.
Perfect crystals don’t exist, and given the practical limitations on purification and impossibility of achieving equilibrium at 0 K, all crystals are expected to have defects. Defect equilibrium plays an important role towards determining several materials properties, but is often overlooked. This presentation provides an introduction to equilibrium chemistry of inorganic solids, with a focus on technologically important metal oxides and electronic properties such as conductivity and diffusion. This presentation is meant for students with little or no background in defect chemistry. It introduces the basic ideas of intrinsic point defects, doping, non-stoichiometry, defect notation, defect equations, charge transport, Brouwer diagrams and some other concepts. At the end, some examples have been taken, where defect chemistry has demonstrated its importance in overcoming practical and scientific challenges.
Nitish Kumar is a Postdoctoral Research Associate at UNSW working with Prof. Mark Hoffman since October 2016. His current research focusses on investigating piezoelectric fatigue mechanisms in novel Pb-free relaxor ferroelectrics. Prior to this, he obtained his PhD degree in September 2016 under the supervision of Prof. David P. Cann at Oregon State University, USA, and Bachelors degree in Materials and Metallurgical Engineering at Indian Institute of Technology, Kanpur, India. He has published 19 peer-reviewed journal articles, filed 1 US patent and delivered 6 invited and contributed conference presentations so far. He has done jobs at Hewlett-Packard Company (USA), Technische Universität Darmstadt (Germany) and Superalloys Plant, Hyderabad (India). He is recipient of several awards such as College of Engineering Outstanding Graduate Research Assistant, Oregon Lottery Graduate Award, Graduate Student Travel Award, first prize at American Society for Metals Student Competition, College of Engineering Fellowship and others.