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MA: Fachverband Magnetismus
MA 11: Multiferroics I: Structure and Phase Transitions (jointly with DF, DS, KR, TT), Program coordination: I. Mertig, M. Fiebig
MA 11.4: Vortrag
Montag, 14. März 2011, 15:30–15:45, HSZ 04
Resonant Soft X-ray Scattering (RSXS) Studies on Multiferroic YMn2O5 — •Sven Partzsch1, Stuart Wilkins2, John Hill2, Enrico Schierle3, Eugen Weschke3, Dmitri Souptel1, Bernd Büchner1, and Jochen Geck1 — 1IFW Dresden — 2BNL Upton — 3Helmholz-Zentrum Berlin
Multiferroic RMn2O5 (R = Y, rare earth, Bi) displays a complex magnetic behavior with transition into a ferroelctric phase as a function of temperature. The intensity of the magnetic superlattice reflection (1/2, 0, 1/4) displays a strong resonance at the Mn L23-edge, due to the strongly increased magnetic sensitivity close to the absorption edge.
Surprisingly, we also observe that this magnetic peak also displays a strong resonance at the oxygen K-edge. The measured integrated intensity of this reflection at the Mn L3-edge in the commensurate and incommensurate magnetic phase is essentially unchanged. At the oxygen K-edge, however, a strong drop of the temperature dependent integrated intensity is observed at the corresponding phase transition, which resembles the temperature dependence of the ferroelectric polarization. Therefore RSXS at the different edges might provide more information about the origin of ferroelectricity in these frustrated magnets.
The experimental data together with LSDA+U calculations provide evidence that magnetically driven charge transfer between oxygen and manganese plays an important role for the ferroelectricity in these frustrated magnets.