Description:

The Department of Materials Science and Engineering welcomes you to its 2016 Winter Colloquium Series.

Location: Tech L361, 4:00pm
Reception to follow

Stephen Pennycook
National University of Singapore

“SCANNING TRANSMISSSION ELECTRON MICROSCOPY: TOWARDS ATOM-BY-ATOM IMAGING IN THREE DIMENSIONS”
In Feynman’s famous 1959 lecture “There’s Plenty of Room at the Bottom,” he challenged us to improve the electron microscope 100 times, so we could “just look at the thing.” With the spectacular advances in aberration correction of the last decade, we have improved image resolution to well below 1 Å and gained a new level of sensitivity to structure, bonding, elemental valence and even spin state. We are able to image atomic diffusion within a solid, identify active sites in a catalyst and explain the unexpected ferromagnetism in ultrathin, insulating LaCoO3-x (LCO) films. We can understand the surprising impact of interface termination on ferroelectricity in BiFeO3 (BFO) films grown on La0.5Sr0.5MnO3-x (LSMO), and how grain boundaries in CdTe solar cells improve cell efficiency. We ca watch the dynamics of nanoclusters and nanowires. But today’s microscope is only 20 times better than in Feynman’s time. If we were to achieve another factor of two in lateral resolution we would achieve a depth resolution at the atomic level, opening the door to microscopic studies of whole new classes of materials by optical sectioning [1-3]. Finally we may be able to see the atomic structure of glasses, nanophase materials and those so-called “random” grain boundaries.

Biography: Stephen J. Pennycook is a Professor in the Materials Science and Engineering Dept., National University of Singapore, an Adjunct Professor in the University of Tennessee and Adjoint Professor in Vanderbilt University, USA. Previously, he was Corporate Fellow in the Materials Science and Technology Division of Oak Ridge National Laboratory and leader of the Scanning Transmission Electron Microscopy Group. He completed his PhD in physics at the Cavendish Laboratory, University of Cambridge in 1978. Pennycook is a Fellow of the American Physical Society, the American Association for the Advancement of Science, the Microscopy Society of America, the Institute of Physics and the Materials Research Society. He has received the Microbeam Analysis Society Heinrich Award, the Materials Research Society Medal, the Institute of Physics Thomas J. Young Medal and Award and the Materials Research Society Innovation in Characterization Award. He has 38 books and book chapters, over 400 publications in refereed journals and has given over 200 invited presentations on the development and application of atomic resolution Z-contrast microscopy and electron energy loss spectroscopy. His latest book is “Scanning Transmission Electron Microscopy.”

Description:

The Department of Materials Science and Engineering welcomes you to its 2016 Winter Colloquium Series.

Marc Walton
Location: Tech L361, 4:00pm

Form, Color, and Function: Understanding the Appearance of Art through Computational Imaging and Materials Analysis

How do you quantify the appearance of a work of art? Simply, take its picture.

New ways of engaging with cultural heritage objects have been made possible with advances in computation and imaging that allow scientists to analyze art non-invasively, historians to better address its function and context, and the general public to explore and interact with art objects in ways never before possible. In this talk, I demonstrate how the Northwestern University / Art Institute of Chicago Center for Scientific Studies in the Arts (NU-ACCESS) has been adapted these methods of computational imaging (e.g., photometric stereo, hyperspectral imaging, super-resolution X-ray fluorescence imaging, and other techniques) to reduce artworks into their basic components of form, color, and visual content. These data provide a better understanding of how artists worked, how these objects were used, and how they have aged over time. Case studies will be presented that show how multiple wavelengths of light illuminated from all directions onto Roman portrait paintings (2nd C. AD) and works by Paul Gauguin (1848-1903) are helping us re-evaluate how the artists created these paintings and drawings. Finally, I will demonstrate how collection of these data is facilitating material classification through the creation of image-based databases and libraries.

Bio: Marc Walton is the Senior Scientist at the Northwestern University / Art Institute of Chicago Center for Scientific Studies in the Arts (NU-ACCESS) and holds an appointment as a Research Associate Professor of Materials Science and Engineering at Northwestern University. Trained in Chemistry and Art History at Clark University, he earned a D.Phil. from the University of Oxford following an MA in art history and a diploma in the conservation of works of art from the Institute of Fine Arts, New York University. Marc worked at the Los Angeles County Museum of Art for two years prior to joining the Getty Conservation Institute in 2005, where he was an associate scientist responsible for the scientific study of antiquities at the J. Paul Getty Museum. He established and ran the analytical laboratory at the Getty Villa site for eight years. His research has focused primarily on trade and manufacture of ancient objects as well as the development of new computation imaging techniques for the analysis of art.

Description:

The Department of Materials Science and Engineering welcomes you to its 2016 Winter Colloquium Series.

David Weitz
Location: Tech L361, 4:00pm

Description:

The Department of Materials Science and Engineering welcomes you to its 2016 Winter Colloquium Series.

Juan Claudio Nino
Location: Tech L361, 4:00pm

"Colossal Effective Permittivity in Ceramics: A Story of Defects”
In the last decades, colossal effective permittivity (CEP, εr > 104-5) has been reported in a number of electronic ceramics. To date, there are several oxide systems that exhibit this phenomenon. Examples include, CaCu3Ti4O12 (CCTO), BaTiO3, K0.3MoO3, Bi1-xLaxNiO3, and more recently co-doped TiO2. In this colloquium presentation, the phenomenon of colossal effective permittivity will be reviewed by focusing on a few of these compounds, to describe our current understanding on the different mechanisms responsible for the observed permittivity (i.e. surface barrier-, grain boundary-, internal barrier-layer capacitor, polaron hopping, etc.). Moreover, recognizing that CEP, is primarily the result of extrinsic and “quenched” intrinsic defects, the effects of composition (precursors, dopants, impurities, etc.), processing (fast firing, reducing atmosphere, etc), and sample preparation (polishing, electroding, annealing) will also be discussed. Further, an attempt to summarize best practices in terms of dielectric characterization that most accurately allow the investigation of the nature of CEP will be made in order to provide a common ground for future research in the field. Finally, an overview of the potential electronics application space for CEP materials will be discussed.

Biography:
Dr. Juan Claudio Nino, is a Professor in the Materials Science and Engineering Department at University of Florida (UF) in Gainesville, FL. He obtained his bachelor’s degree in Mechanical Engineering in 1997 at Los Andes University (Bogotá, COLOMBIA). He was a Lecturer at the Colombian Engineering School before joining The Pennsylvania State University in 1998, where he completed his doctoral degree in Materials Science and Engineering in 2002. After a postdoctoral appointment focusing on ferroelectric thin films at the Materials Research Institute (State College, PA), he joined UF in Fall 2003 as an Assistant Professor. Since, he has established the Nino Research Group (NRG) with main focus of the investigation of fundamental relationships governing energy-related materials towards enhancing their efficiency, performance, and sustainability. NRG’s research investigates ceramics, polymers, bio-inspired materials, and their composites. With over 100 publications in the field and four patents, current research focus includes optimization and development of materials for: (a) electrolytes and cathodes for ionic and protonic conduction devices, (b) high frequency and high temperature dielectrics, ferroelectrics and piezoelectrics, (c) porous ceramics and composite foams, and (d) semiconductors and scintillators for radiation detection. He is a recipient of the CAREER award by the US National Science Foundation. In 2009 he received the J Bruce Wagner Jr Young Investigator Award from the Electrochemical Society. In 2014 he received the Fulbright US Scholar Innovation and Technology Award from the US Department of State. He is an Associate Editor for the Journal of the American Ceramics Society, and a Coordinating Editor for the Journal of Electroceramics.

Description:

The Department of Materials Science and Engineering welcomes you to its 2016 Winter Colloquium Series.

Yuri Suzuki
Location: Tech L361, 4:00pm

"Emergent Phenomena at a Mott Insulator/ Band Insulator Interface”
Advances in solid-state devices have been enabled by the introduction of new materials platforms and their subsequent improvements in carrier concentration, mobility and breakdown voltages. To this end, the exploration of interfaces, where a novel functionality or phenomenon is generated at the interface of two materials that is not present in either of the bulk forms of the constituent materials, is promising. With recent developments in complex oxide thin film deposition techniques, novel ground states at perovskite oxide interfaces have been studied intensively in order to understand the role of mismatches in bands, valences, and interaction lengths. The most well-known example of such emergent phenomena at complex oxide interfaces has been the discovery of metallicity at the interface of two band insulators LaAlO3 and SrTiO3. We have recently discovered that low dimensional metallic behavior at the interface of a Mott insulator LaTiO3 and a band insulator SrTiO3 is characterized by quantum oscillations and strong in-plane anisotropic magnetoresistance. Our previous work showed that metallicity can be induced in the bulk of a LaTiO3 film grown on a SrTiO3 substrate. Once the LaTiO3 film thickness is decreased down to 3 unit cells, we observe metallicity associated with the interface. This metallicity is characterized by Shubnikov de Haas oscillations that appear around 1T but unexpectedly disappear by 4T. The frequency of oscillations of 3.7 +/- 0.7T corresponds to a small cross sectional orbit of 0.015 +/- 0.003% of the first Brillouin zone. The area of the pocket in the Fermi surface causing the oscillations is so small that by 4 T the system reaches the quantum limit in which all of the electrons in that pocket are in the lowest Landau level, thus explaining the disappearance of the oscillations by 4T. A Berry’s phase of is deduced from the Shubnikov de Haas oscillations and can be attributed to a large Rashba coupling. This is consistent with the observed in-plane anisotropic magnetoresistance as both its size and magnetic field dependence have been theoretically predicted for a system with a very strong Rashba effect. Such a large Rashba coupling suggests that such a Mott/band insulator interface may be an excellent candidate for spintronics.

Biography:
Yuri Suzuki received an A.B. in physics magna cum laude with high honors from Harvard University in 1989 followed by a Ph.D. in Applied Physics from Stanford University in 1995. During her graduate career, she performed research on high temperature superconductivity and complex oxide thin films with NSF and ARCS Foundation fellowships. As a postdoctoral member of technical staff at AT&T Bell Labs (1994-1996), she moved into the field of magnetism. She then assumed an assistant professor position at Cornell University in the Department of Materials Science and Engineering (1997) and was later promoted to associate professor (2001). She moved to UC Berkeley in 2003 as an associate professor and was later promoted to professor in 2008. She is currently in the Department of Applied Physics at Stanford where she moved to in 2012. She has been recognized with an NSF Career Award, ONR Young Investigator Award, Packard Foundation Fellowship, Robert Lansing Hardy Award of TMS, Maria Goeppert-Mayer Award of the American Physical Society, American Competitiveness and Innovation Fellowship of the National Science Foundation, Fellowship in the American Physical Society and the DoD National Security Science & Engineering Faculty Fellowship.