Dresden 2011 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 19: Poster I (Bio- and Molecular Magnetism/ Magnetic Particles and Clusters/ Micro- and Nanostructured Magnetic Materials/ Magnetic Materials/ Multiferroics/ Magnetic Shape Memory Alloys/ Electron Theory of Magntism/ Spincaloric Transport/ Magnetic Coupling and Exchange Bias/ Magnetization Dynamics/ Micromagnetism and Computational Magnetics)
MA 19.50: Poster
Dienstag, 15. März 2011, 10:45–13:00, P2
Nonlinear optical spectroscopy on magnetoelectric and multiferroic pyroxenes LiFeSi2O6 and NaFeSi2O6 — •Adrian Volz1, Naëmi Leo1, Petra Becker2, Ladislav Bohatý2, and Manfred Fiebig1 — 1HISKP, Universität Bonn — 2Institut für Kristallographie, Universität zu Köln
There has been a growing interest in the class of pyroxenes AMSi2O6 (A alkali metal, M transition metal) with multifunctional properties such as multiferroicity or magnetic-field controllable electric polarization. In particular the close relation between toroidal moment and the observed cross-coupling of magnetic and electric properties are discussed for multiferroic NaFeSi2O6 and magnetoelectric LiFeSi2O6.
Here we characterize the pyroxene compounds LiFeSi2O6 and NaFeSi2O6 by optical second harmonic generation (SHG). SHG is particularly sensitive to the subtle symmetry issues distinguishing between the magnetoelectric and the multiferroic properties of the pyroxenes. We observe gigantic SHG effeciency which indicates electronic (i.e. non-ionic) contributions to the magnetically induced spontaneous polarization. By SHG spectroscopy we seperate signals of crystallographic, magnetic and electric origin which allows us to investigate the interaction between the corresponding sublattices. The influence of externally applied fields is discussed.
This work is supported by the DFG through SFB 608.