Dresden 2011 – wissenschaftliches Programm
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KR: Fachgruppe Kristallographie
KR 5: Poster Multiferroics (Joint Session of MA, DF, DS, KR, TT)
KR 5.51: Poster
Dienstag, 15. März 2011, 10:45–13:00, P2
Magneto-electric coupling in NdFe3(BO3)4 studied by resonant x-ray scattering — •J. E. Hamann-Borrero1, S. Partzsch1, S. Valencia2, R. Feyerherm2, C. Mazzoli3, J. Herrero-Martin3, C. Hess1, A. Vasiliev4, L. Bezmaternykh5, B. Büchner1, and J. Geck1 — 1IFW Dresden, 01171 Dresden — 2Helmholtz Zentrum Berlin. Albert Einstein Str. 15 12489 Berlin — 3ESRF, Boite Postale 220, 38043 Grenoble, France — 4Faculty of Physics, Moscow State University, Russia. — 5Kirensky Institute of Physics, Russian Academy of Sciences, Krasnoyarsk, Russia.
Resonant x-ray magnetic scattering (RXS) experiments on NdFe3(BO3)4 were performed at the Nd L2,3 and Fe K edges in order to determine its magnetic structure as a function of temperature (T) as well as applied magnetic (B) and electric (E) fields. Results of the T dependent measurements show that the magnetic structure changes from a commensurate collinear structure to an incommensurate spin helix structure. Moreover, the analysis of the resonant intensities shows that the T dependence of the magnetic order is different for the Nd and for the Fe sublattice. A mean field analysis implies that the magnetization of the Nd sublattice is induced by the Fe magnetization. When a B field is applied along the a-direction, the spin helix is destroyed and a collinear structure is formed where the moments align perpendicular to B. Since the critical B at which the spin helix is destroyed is the same at which the magnetic induced electric polarization is maximum. This shows that the spin helix is not the origin of the electric polarization in NdFe3(BO3)4.