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Physics and Astronomy

Physics & Astronomy Colloquium

3:30 PM, Friday, September 17, 2010
Room 155, Chem-Phys Building

Dr. Jaime Fernandez-Baca
Neutron Scattering Science Division, Oak Ridge National Laboratory
Department of Physics and Astronomy, University of Tennessee, Knoxville

Spin excitations in multiferroic CuFeO2
In this talk I present highlights of our studies of the triangular-lattice geometrically frustrated antiferromagnet system Cu(Fe-Ga)O2 using neutron and x-ray scattering. These studies were focused in the understanding of the nature of the lattice distortions and of the spin interactions in the parent compound of this system CuFeO2 which is paraelectric, and in the doped compound Cu(FeGa)O2 which exhibits multiferroic behavior. While the multiferroic phase in this material is associated to a non-collinear incommensurate spin structure, this compound has the distinction of not satisfying the so-called Katsura relationship in which the electric polarization is expected to be proportional to the cross product of the magnetic propagation wavevector and the spin rotation axis. Thus the study of this multiferroic system is of importance to give light about alternative mechanisms of magnetoelectric coupling.

Refreshments will be served in CP 179 at 3:15 PM