Materials Science and Engineering Colloquium
Date: November 21, 2014 from 11:00 am to 12:00 pm EST
Location: Columbia University, Morningside Campus
S.W. Mudd, Room 214
Contact: For further information regarding this event, please contact William Bailey by sending email to web54@columbia.edu or by calling 212-854-3090.
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Paul Evans

University of Wisconsin, Madison

"Phase transitions, domains, and fluctuations in the dynamics of complex oxides"

The functional properties of complex oxide electronic materials including ferroelectrics and multiferroics can be readily controlled by inducing subtle changes in the crystal structure.  Static variations of the structural properties, for example modulating the composition or biaxial strain, have provided exceptional opportunities in the design of piezoelectric, dielectric, and magnetic materials. Beyond such steady-state properties, however, the structure of these materials exhibits a wide range of dynamical variations that represent a new frontier in the control of their properties. These dynamics can be initiated by external optical or electric fields, range over timescales from picoseconds to hours, and can have profound effects on electronic properties. Emerging synchrotron x-ray scattering techniques provide new insight into these phenomena, including the dynamics of self-organized nanoscale striped polarization domains in ferroelectric superlattices and electrically controlled structural phase transitions in multiferroics. In emerging areas the high degree of spatial coherence of x-ray sources now permits the mesoscopic fluctuations of domain patterns to be probed using x-ray photon correlation spectroscopy and ultrafast optical techniques permit the generation of structural transients with onset times as short as several picoseconds.

Host: William Bailey