MIE Special Seminar with Professor Long-Qing Chen
The Department of Mechanical and Industrial Engineering Presents
Professor Long-Qing Chen
Department of Materials Science and Engineering Materials, Research Institute Pennsylvania State University University Park, PA 16802
Topic: Strain Engineering of Phase Transitions, Domain Structures, Properties of Nanoscale Ferroelectric Thin Films
Date: Monday, March 10, 2014
Time: 10:30am to 12:00pm (Refreshments from 10:00am to 10:30am)
Location: 333 Curry Student Center
Abstract: Many applications of materials require the growth of thin films on a substrate. It is known that the interface between an epitaxial film and a substrate is coherent when a film thickness is small, i.e. below the critical thickness for nucleation of interfacial dislocations. This presentation will discuss the applications of fundamental thermodynamics and phase-field simulations to predicting phase transitions, domain structures, and properties of ferroelectric thin films. Examples to be discussed are drawn from recent collaborations with numerous experimental groups on oxide film growth and characterizations, including PbTiO3, PbxZr1-xTiO3(PZT), BaTiO3, BiFeO3 and superlattices. It is shown that ferroelectric transition temperatures in thin films can be shifted by hundreds of degrees as compared to the corresponding bulk crystals. It is also demonstrated that strain and electric boundary conditions can drastically modify the domain structures of a thin film as well as its properties such as coercive field, spontaneous polarization, and piezoelectric responses. It will be shown that one can use phase-field simulations to not only help interpret experimental observations but also provide guidance to achieve desirable transition temperatures, specific domain states, and domain wall orientations.
Bio-Sketch: Chen is Distinguished Professor of Materials Science and Engineering, Engineering Science and Mechanics, and Mathematics at the Pennsylvania State University. He received his B.S. degree in Materials Science and Engineering from Zhejiang University in China in 1982. After spending one year as an assistant instructor at Zhejiang University, he received his M.S. degree in Materials Science and Engineering from Stony Brook University in 1985 and a Ph.D. degree in Materials Science and Engineering from the Massachusetts Institute of Technology (MIT) in 1990. After a two-year postdoc appointment at Rutgers University with Armen Khachaturyan, he joined the faculty at Penn State in 1992. He has received numerous awards for his work including ONR Young Investigator Award (1995), Penn State University Faculty Scholar Medal in Engineering (2003), Guggenheim Fellow (2005), American Physical Society (APS) Fellow (2008), TMS EMPMD Distinguished Scientist/Engineer Award (2011), ASM Fellow (2012), and Materials Research Society (MRS) Fellow (2013).
Monday, March 10, 2014 at 10:30am to 12:00pm
Curry Student Center, 333csc