Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 8: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 8.3: Vortrag
Montag, 25. Februar 2008, 14:30–14:45, H 0104
Spherical neutron polarimetry of the magnetic structure in MnSi — •Marc Janoschek1, Florian Bernlochner1, Sebastian Mühlbauer1,2, Robert Georgii1,2, Christian Pfleiderer1, and Peter Böni1 — 1Physik-Department E21, Technische Universität München, D-85748 Garching, Germany — 2Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universität München, D-85748 Garching, Germany
Dzyaloshinsky-Moriya interactions stabilize a long-wavelength spin spiral (λ∼ 190 Å) in the magnetically ordered state of B20 compound MnSi. Recent theoretical studies [1] suggest that the DM interactions may not only stabilize straight-forward helical order, but also additional complex magnetic textures, when the amplitude of the local magnetization is soft and supports strong longitudinal fluctuations, e.g. near critical phase transitions. Polarized neutron scattering provides a unique microscopic tool for the determination of magnetic structures. We have explored the question of the magnetic order and related magnetic textures in MnSi by means of spherical neutron polarimetry using the module MuPAD. We have focussed in particular on the nature of the magnetic state in the vicinity of the helical to paramagnetic phase boundary, where bulk properties reveal weak evidence for additional phase transitions. [1] U. K. Rößler, A. N. Bogdanov, C. Pfleiderer Nature 442, 797 (2006).