Workshop 2

"Probing Nano-scale Inhomogeneities in Transition Metal Oxides Using High Energy X-ray Diffraction and Scanning Microscopy"

Date: Monday, May 21, 2007

Organizer(s):
Markus Hucker (Condensed Matter Physics and Material Science Dept., BNL) huecker@bnl.gov
Guangyong Xu Condensed Matter Physics and Material Science Dept., BNL) gxu@bnl.gov
Zhong Zhong (National Synchrotron Light Source, BNL) zhong@bnl.gov

Location: Bldg. 463, Biology, Seminar Room

Description:

One of the key challenges in materials science is to understand the role that local inhomogeneities play in altering, and in many cases, dramatically enhancing material properties. This is particularly evident in transition metal oxides and related compounds. Some examples include ”stripes” in high temperature superconductors, ”polar nano-regions” in relaxor ferroelectrics, and ”polarons” in materials with colossal magnetoresistance. X-ray diffraction/scattering is among the most direct probes that can be used to analyze the structural properties and dynamics of these inhomogeneities. It is often desirable in these studies that a high energy x-ray beam with large penetration depth is used. E.g., some of the work requires extreme external conditions (e.g. high pressure); while certain materials show different bulk and surface properties (e.g. in lead-perovskite relaxors).

The focus of the workshop will be to review recent work in the field with high energy x-ray diffraction/scattering, and to identify key scientific questions that can be solved using this technique. A high energy x-ray beam line is currently available at the NSLS, and significantly improved as well as currently impossible experiments should become available with a third generation synchrotron, such as the planned NSLS-II.

Specific topics in the workshop include: high energy x-ray diffraction studies of stripes in high-Tc cuprates under high pressure; high energy x-ray diffuse scattering studies of polar nano-regions in relaxor ferroelectrics under external field and/or pressure; comparison of x-ray results with other complementary techniques, e.g. STM/PFM (piezoelectric force microscopy); and future development of high energy x-ray beam lines.

This workshop should be of interest to a broad audience interested in nanoscopically inhomogeneous materials, such as high-Tc superconductors and dielectric/ferroelectric materials. It will also attract researchers in the x-ray and neutron scattering communities who are interested in learning and developing novel scattering techniques.