Predicting grain-boundary transport properties in a perovskite oxide
Roger A. De Souza
Institute of Physical Chemistry, RWTH Aachen University
rdesouza@pc.rwth-aachen.de
Department of Materials Science and Engineering
Massachusetts Institute of Technology
Special Materials Seminar
1pm Tuesday, July 7, 2009
Chipman Room :: 6-104
The transport of charge and mass across grain boundaries in acceptor-doped SrTiO3 is known to be hindered. In this contribution the thermodynamics of space-charge formation is examined. Thermodynamic models are presented, which predict the space-charge potential as a function of thermodynamic variables, such as dopant concentration, temperature and oxygen partial pressure. These models are subsequently applied to electrical impedance data reported in the literature for tilt bicrystal samples of Fe-doped SrTiO3. Thermodynamic driving forces for space-charge formation are examined as a function of tilt misorientation angle with the aim of extracting correlations between the driving forces for space-charge formation and interface atomistic structure.
Prof. Krystyn Van Vliet is one of eighty-eight of the nation’s brightest young engineers who have been selected to take part in the National Academy of Engineering’s (NAE) 15th annual U.S. Frontiers of Engineering symposium. Engineers ages 30 to 45 who are performing exceptional engineering research and technical work in a variety of disciplines will come together for the 2-1/2-day event. The participants – from industry, academia, and government – were nominated by fellow engineers or organizations and chosen from approximately 240 applicants.
“In today’s challenging economic times, we look more than ever toward our engineering innovators,” said NAE President Charles M. Vest. “The U.S. Frontiers of Engineering program brings together a diverse group of this country’s most promising young engineers, and gives them a forum to discuss multi-disciplinary ways of addressing the issues that will carry us into tomorrow’s economy.”
The symposium will be held Sept. 10-12 at the National Academies’ Beckman Center at the University of California, Irvine, and will examine engineering tools for scientific discovery; engineering the health care delivery system; nano/micro photonics and new applications; and resilient and sustainable infrastructures. A featured speaker will be Bradford W. Parkinson, Edward C. Wells Professor of Aeronautics and Astronautics Emeritus at Stanford University. Parkinson is credited with being the father of the Global Positioning System and is a recipient of the prestigious Draper Prize and a member of the NAE.
The materials community is invited to attend a special presentation by Dr. Hilary Crichton, Associate Editor of Nature Materials:
Thursday, June 25 at 4:00 pm
Room 3-270
Dr. Crichton will deliver an overview of the journal, including insight into what the editorial team looks for in submissions, and tips on how researchers can best present their work.
Dr. Crichton joined Nature Materials in June 2008 after almost four years working as an assistant editor for the Royal Society of Chemistry, where she handled papers for Physical Chemistry Chemical Physics and Faraday Discussions. She is responsible for manuscripts concerning all aspects of physical chemistry, including materials chemistry and organic conductors. She obtained her Master of Chemistry degree at the University of Edinburgh, UK, and a PhD in physical chemistry at Heriot-Watt University, UK.
Michael Demkowicz, an assistant professor in MIT’s Department of Materials Science and Engineering, is part of a team based at Los Alamos National Laboratory that recently received a federal Energy Frontier Research Centers grant to develop nanocomposite materials that can endure high temperatures, radiation and extreme mechanical loading. The ultimate goal is to use these materials in energy applications including nuclear power, fuel cells, solar energy and carbon sequestration.
Prof. Yoel Fink and other researchers at MIT have integrated a collection of light sensors into polymer fibers, a development with potential to be used as a camera. Prof. Fink’s previous work integrated semiconducting materials into fibers, resulting in fabrics with sensors for temperature and light. This work integrates eight sensors into a polymer fiber.
