Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 3.9: Vortrag
Montag, 23. März 2009, 12:30–12:45, HSZ 304
Inelastic neutron scattering study of helimagnons in MnSi — •Marc Janoschek1,2, Florian Jonietz1, Sarah Dunsiger1, Christian Pfleiderer1, Peter Böni1, Bertrand Roessli2, Peter Link3, and Achim Rosch4 — 1Physik Department E21, Technische Universität München, D-85748 Garching — 2Paul Scherrer Institut, CH-5232 Villigen PSI — 3Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), Technische Universität München, D-85748 Garching — 4Institute of Theoretical Physics, Universität zu Köln, D-50937 Köln, Germany
In zero field the lack of inversion symmetry in MnSi results in a weak Dzyaloshinsky-Moriya interaction, that stabilises a spin spiral with a period of approximately 180Å below Tc = 29.5 K. Recent theoretical studies [1,3] predict a rich spectrum of Goldstone modes in the helical phase for wave vectors that are small compared to the helical propagation vector. These excitations, also referred to as helimagnons, are predicted to have a characteristic anisotropic dispersion relation with respect to the propagation direction of the spiral. We have performed extensive inelastic neutron scattering experiments by means of triple-axis spectroscopy in order to explore the nature of these excitations. The measurements have been carried out in the helical phase and in the A-phase where a skyrmion lattice has been observed recently[3].
[1] D. Belitz, T. R. Kirkpatrick and A. Rosch Phys. Rev. B 73, 054431 (2006).
[2] S. V. Maleyev, Phys. Rev. B 73, 174402 (2006).
[3] S. Mühlbauer, B. Binz, F. Jonietz, C. Pfleiderer, A. Rosch, A. Neubauer, R. Georgii, P. Böni, (2008).