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DF: Fachverband Dielektrische Festkörper
DF 5: Poster Session on Ferroic Domain Walls - Multiferroics (DF with KR/MA/TT)
DF 5.6: Poster
Montag, 16. März 2015, 19:00–21:00, Poster C
Raman Spectroscopy and Spin-Phonon-Coupling of Multiferroic Eu1−xHoxMnO3 — •Sebastian Elsässer1, Jean Geurts1, Vladimir V. Glushkov2, and Anatoly M. Balbashov2 — 1Exp. Phys. III, University of Würzburg, Germany — 2Prokhorov GPI, Russian Academy of Sciences, Moscow, Russia
The revival of studies on magneto-electric (ME) effects has led to rich insights in the physics of charge and spin degrees of freedom and their mutual interaction via ME coupling [1]. One of the most extensively studied effects is the inverse Dzyaloshinskii-Moriya interaction. Hereby, the ordering of the magnetic moments leads to a lattice distortion which, in turn, can induce in a permanent electric polarization. This manifests itself in the perovskite-like rare-earth manganites RMnO3. Here, the average size of the rare-earth ions R3+ directly influences the octahedron tilting angle. This can be used to tune the coupling between the magnetic Mn sites yielding model system for the interplay of crystalline distortion, magnetic frustration and electric polarization. In this study, R= Eu3+ ions are partially replaced with Ho3+ (<30%) to achieve the multiferroic phase. Spin-phonon-coupling (SPC) is probed by temperature-dependent Raman spectroscopy. We identify the elusive peak at 650cm−1 to be the B3g(1) mode. Upon cooling renormalisation of phonon energies due to SPC-effects starts already well above TN. We observe that the SPC-shift is mode-specific, being strongest (up to 1%) for the B2g(1) and B3g(1), which are both octahedron breathing modes.
[1] M. Fiebig, Journal of Physics D-Applied Physics 38, 8 (2005)