Graduate School in Nonlinear Science

Sponsored by The Danish ResearchAgency

MIDIT                              OFD                          CATS
Modelling, Nonlinear Dynamics      Optics and Fluid Dynamics    Chaos and Turbulence Studies
and Irreversible Thermodynamics    Risø National Laboratory     Niels Bohr Institute and
Technical University of Denmark    Building 128                 Department of Chemistry
Building 321                       P.O. Box 49                  University of Copenhagen
DK-2800 Lyngby                     DK-4000 Roskilde             DK-2100 Copenhagen Ø
Denmark                            Denmark                      Denmark


by A. Saxena
Los Alamos National Lab. USA

MIDIT-seminar 511

Tuesday, August 27, 2002, 14.00 h
at IMM, Bldg. 305, Room 130, DTU

Abstract: High resolution microscopies of several classes of functional materials have revealed fascinating nonlinear phenomena including intrinsically inhomogeneous microstructure, with multiscale modulations of charge, spin, polarization and strain. These material classes include manganites, ferroelastic martensites, shape memory alloys, relaxor ferroelectric titanates, magnetoelastics, for which stripe- or island-like patterning of charge, magnetization, polarization and strain, extend over many lattice spacings. This "texturing" affects electronic, magnetic and structural properties of the materials. We show that long-range anisotropic strain interactions arising from general elastic compatibility considerations, linking strain tensor components, can enable interfaces or atomic-scale defects, to induce global strain textures. Symmetry-allowed couplings between strains and electronic and magnetic variables can then generate effective strain-mediated long-range interactions between these variables.