Northwestern Events Calendar

Feb
14
2017

Exploiting X-Ray Coherence in Nanomaterials Science

recurring see all events in this series

When: Tuesday, February 14, 2017
4:00 PM - 5:00 PM CT

Where: Technological Institute, Tech L211, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: Faculty/Staff - Student - Post Docs/Docs - Graduate Students

Contact: Department Office   (847) 491-3537

Group: Department of Materials Science and Engineering (MatSci)

Category: Lectures & Meetings

Description:

Exploiting X-Ray Coherence in Nanomaterials Science

By: Paul Evans

Abstract: The development of novel functional materials presents a series of characterization challenges, particularly in understanding how to employ the relationship between structural parameters and functional properties such as ferroelectricity and magnetism. X-ray scattering methods based on diffraction, scattering, and spectroscopy have in the past provided structural insight into large and static ensembles of nanomaterials but have had limited applicability to individual nanostructures or to non-equilibrium conditions. The rapid development of x-ray sources with improved x-ray optical coherence now makes it possible to probe nanomaterials under a much wider range of conditions, including transient far-from-equilibrium states and the structure and properties of individual 10-nm-scale nanostructures. My group’s research emphasizes the development and application of these advanced x-ray scattering methods. In this talk I will first describe x-ray nanobeam techniques enabled by x-ray coherence and the application of these tools to challenging problems in the structure of materials for quantum electronic devices. Recent developments in the forward simulations of diffraction experiments, including both coherent scattering and dynamical diffraction phenomena, provide a guide to the interpretation of experimental data. Coherence has likewise enabled us to probe the dynamics of equilibrium fluctuations in ferroelectric nanomaterials and of non-equilibrium states in ferroelectric and multiferroics reached by transient optical or electric-field excitation. By combining nanobeam techniques with time-resolved scattering we have discovered that both optical and electrical excitation leads to large lattice distortions and to structural phase transformations that promise new ways to control electronic and magnetic properties.

Bio: Paul Evans is a Professor in Materials Science and Engineering at the University of Wisconsin-Madison, where his research interests are at the intersection of the development of electronic materials and the creation and application of novel methods in x-ray science. Before moving to the University of Wisconsin in 2002, Evans received his doctorate in Applied Physics in from Harvard University in 2000 and spent two years as a postdoctoral research in the Physical Sciences Research Division at Bell Laboratories. His professional activities have included advisory roles at several synchrotron light sources and an extended sabbatical visit to the European Synchrotron Radiation Facility.

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