Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Poster Session on Ferroic Domain Walls - Multiferroics (jointly with DF, KR, MA)
TT 28.20: Poster
Montag, 16. März 2015, 19:00–21:00, Poster C
Inelastic neutron scattering studies on LuFe2O4 — •Hailey Williamson1, Petr Čermák3, Jörg Voigt1, Ryoichi Kajimoto4, Geetha Balakrishnan2, and Manuel Angst1 — 1Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH, Germany. — 2Department of Physics, The University of Warwick, UK. — 3Jülich Centre for Neutron Science JCNS, Forschungszentrum Jülich GmbH, Outstation at MLZ, Germany. — 4Neutron Science Section, MLF Division, J-PARC Centre, Japan
Multiferroic oxides, which exhibit a coupling between magnetism and charge order (CO), constitute a strong and competitive avenue of research. The well-known LuFe2O4, the first proclaimed multiferroic through CO due to mixed valence Fe2+/3+ bilayers separated by Lu monolayers, was initially thought to produce ferroelectricity through polarization, from the specific CO configuration within the bilayers. This fuelled intense investigation, leading to the conclusion through XMCD, bond valence sum analysis of data and macroscopic characterization, that the bilayers are charged and not polar. With much of the static crystallographic and magnetic properties uncovered, it is now essential to elucidate the dynamic properties to understand how the spin and charge are coupled. Here we present quasi-elastic magnetic scattering with a profound temperature dependence, as well as phonon dispersions at higher energies. Finally, we show an indication of a spin gap opening, on cooling through the magnetic ordering temperature.