Graduate School in Nonlinear Science
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
NONLINEAR PHENOMENA IN FUNCTIONAL MATERIALS
by A. Saxena
Los Alamos National Lab.
Tuesday, August 27, 2002, 14.00 h
at IMM, Bldg. 305, Room 130, DTU
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.