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Tutorial CP03—Mini X-Ray and Neutron School on In Situ Materials Research

Apr 22, 2019
08:30 AM - 05:00 PM
PCC North, 100 Level, Room 126 A

The application of x-ray and neutron facilities are useful and powerful analysis routes for characterizing materials from a broad range of research communities. With the development of new generations of synchrotron x-ray and neutron facilities across the world, there is increasing demand on how to take full advantage of these state-of-the-art techniques and tailor them for individual research areas.  The main purpose of the x-ray and neutron technique tutorial session is to educate conference attendees on the utilization of major neutron and x-ray facilities for in situ characterization of materials synthesis and function under operating conditions. The leading researchers from U.S. DOE national laboratories will present the lectures, including basic tutorials on the neutron and x-ray facilities, the characteristics of the sources and related beamlines, the principles of scattering and spectroscopy, data processing and modeling, as well as topics on applications to a variety of scientific subjects. The latest progress and ideas will also be discussed, both on experimental and analytical methods for in situ materials research using x-ray and neutron sources.

8:30 am—Introduction to X-Ray Absorption Spectroscopy
Steve M. Heald, Argonne National Laboratory

The x‐ray absorption fine structure (XAFS) that is present near x‐ray absorption edges contains detailed information about the local structure and bonding of the absorbing atoms. With the advent of intense tunable sources of x-rays using synchrotron radiation facilities, the application of x‐ray absorption spectroscopy has become widespread and routine. The XAFS is a local probe sensitive to the location and type of atoms surrounding the absorbing atom. As a local probe, it can be applied to many materials where diffraction‐based techniques would be impractical, such as resolving the structure near highly dilute components and determining the local structure of atoms in nanoparticles, liquids, metalloproteins in solution, amorphous solids and poorly crystalline materials. In addition to the direct structural information, the absorption edge position and shape can be used to determine the site symmetry and valence of the absorbing atoms. In this tutorial, an introduction to XAFS will be given, and the basic steps for data analysis including examples will be demonstrated.

10:00 am—BREAK

10:30 am—Material Insights from Total Scattering Data: A Tour of Small Box Modeling and More
Katharine L. Page, Oak Ridge National Laboratory

Total scattering (and the associated pair distribution function technique), an extension of diffraction methods, is increasingly prevalent in modern materials studies. The unique combination of Bragg and diffuse scattering has related vacancies in high-temperature ceramics to both their superionic conductivity and phase stability, nanometer-sized polar domains or nanoregions in relaxor ferroelectrics to their enhanced dielectric and piezoelectric properties, and vacancy/disorder arrays and other subtle local correlations to the mechanisms of high-Tc superconductivity. These methods have further proven critical in understanding guest–host interactions, amorphous to crystalline transitions, local spin correlations and other disordered crystalline materials phenomena. This lecture and tutorial is aimed at introducing neutron total scattering, community software and refinement methods to new and beginning users. The lecture will focus in providing a technical foundation and highlighting exemplary work in the community, while the tutorial will include both demonstration and hands-on training with community software.  We will also introduce available instruments (including our mail-in programs), sample environments and resources for first time and beginning practitioners.  A special emphasis will be placed on the growing number of in situ and in operando capabilities at the neutron total scattering beamlines at the Spallation Neutron Source at Oak Ridge National Laboratory.

1:30 pm—Synchrotron X-Ray and Neutron Diffraction Techniques for In Situ and Operando Studies of Energy Materials
Yang Ren, Argonne National Laboratory

This part of the tutorial will be focused on synchrotron x-ray and neutron diffraction techniques for in situ and operando studies of energy materials during synthesis and operation. General knowledge of synchrotron x-ray and neutron diffraction techniques and their complementarity for energy materials research will be introduced first. Some examples on synchrotron x-ray and neutron study of energy materials will be presented, for example, in situ/operando characterizing battery electrode materials during high-temperature formation as well as during charging/discharging processes, in situ probing transformation of ferroelectric ceramics under electric field or transforming alloys under mechanical stress, etc. Finally, future perspectives of synchrotron and neutron diffraction techniques for in situ/operando study of energy materials will be discussed.

3:00 pm—BREAK

3:30 pm—Local Symmetry Breaking in Functional Materials: A Tour from Quantum to Energy to Strange
Emil Bozin, Brookhaven National Laboratory

The total-scattering-based PDF approach has been instrumental to understanding the local and intermediate range structure of complex functional materials. From standard to more advanced techniques, such as time-resolved, dynamic, magnetic, thin film, and computed tomography approaches, the PDF method enables exploration of a diverse class of problems in contemporary materials science.

These include sustainable energy materials (e.g., battery and hydrogen storage materials, thermoelectrics), soft materials (e.g., drugs, polymers, sugars, cellulose), soft hard materials (e.g., strongly correlated electron systems, nanoparticles, catalysts), as well as materials displaying “strange” properties (e.g., negative thermal expansion, amorphization and amorphous materials, negative linear compressibility). This part will highlight the power of x-ray and neutron total scattering and PDF applications through selected illustrative examples. Focus will be placed on exploring dynamic local symmetry breaking in novel materials, emphasizing that this local symmetry breaking is the key for understanding devices from energy conversion to superconductivity. We will demonstrate that local, fluctuating broken symmetry states are widespread in functional materials.