Abstract

Progress in advanced functional materials is reliant on understanding interactions and heterogeneity at nanometer-to-micrometer length scales. The nanoscale heterogeneities alter the structural, magnetic, electronic, and electrochemical behavior; they govern the physical processes and macroscopic properties in matter. In particular, nanostructured complexes' interactions in liquids govern the phase separation phenomena, and local polar nano-domains play an essential role in ferroelectrics macroscopic properties. Despite significant efforts in discovering and characterizing macroscopic states of matter, progress in understanding the fundamental mechanisms behind these phenomena often encounters challenges in probing structural dynamics of matter at the nanoscale. Recent developments in coherent x-ray sources and methods significantly advance the capabilities of nanoscale measurements, offering superb spatial and temporal resolution (ultrasmall and ultrafast). In this seminar, I will present our recent research activities utilizing X-ray Photon Correlation Spectroscopy (XPCS), a powerful coherent X-ray method, to probe dynamics of local heterogeneities. I will introduce the XPCS method and present applications in soft and crystalline condensed matter. XPCS and the new high-speed X-ray detector systems provide a golden opportunity to shed new light on a problem of both practical and fundamental importance – the dynamics of fluctuations near critical points in complex fluids in soft matter. I will also show our recent experimental results on domain dynamics in relaxor ferroelectrics achieved with wide-angle XPCS.

Biography

Dina Sheyfer graduated from National Research Nuclear University MEPhI (Moscow, Russia) with specialist degree in condensed matter physics. She obtained her PhD degree in the field of coherent X-ray scattering physics from the University of Hamburg being working at the group of prof. G. Grübel at DESY (Hamburg, Germany). During her PhD she applied coherent X-ray scattering techniques – X-ray Photon Correlation Spectroscopy (XPCS) and X-ray Cross Correlation Analysis - to study structure and dynamics in soft matter systems. The postdoctoral research she did in the group of Dr. S. Hruszkewycz at Material Science Division at Argonne National Laboratory. During her postdoc she studied dynamics of liquid-liquid extraction systems utilizing new fast detectors and XPCS methods. She also performed various in-situ type research: utilizing XPCS to probe ferroelectrics domain dynamics under applied electric field; probing structural response of platinum under electrocatalytic reaction conditions with Bragg Coherent Diffractive Imaging. Since February 2021 she became a staff scientist at Advanced Photon Source of Argonne National Laboratory. She continues her research projects and provides support to users at the Laue Microdiffraction beamline (sector 34IDE at APS).