Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Correlated Electrons: Spin Systems, Itinerant Magnets 3
TT 28.8: Vortrag
Dienstag, 12. März 2013, 11:30–11:45, H19
Neutron polarimetry of the fluctuation-induced first order helimagnetic transition in MnSi — •Jonas Kindervater1, Wolfgang Häußler1,2, Markus Garst3, Marc Janoschek4, Christian Pfleiderer1, and Peter Böni1 — 1Physik Department E21, TU München — 2Forschungsneutronenquelle Heinz Maier-Leibnitz, TU München — 3Institute for Theoretical Physics, Universiät zu Köln — 4Los Alamos National Laboratory
Chiral magnets, like the B20 compound MnSi, have recently attracted much scientific interest because a new spin structure representing a skyrmion lattice has been identified under moderate magnetic fields [1]. Besides these topological spin textures the phase transition from heli- to paramagnetism in MnSi has been under active investigation. Different scenarios on the mechanism of the transition have been proposed, ranging from a topological skyrmion liquid phase [2] over a second order mean field transition [3] to a fluctuation induced first order Brazovskii phase transition [4] that was recently confirmed experimentally in small angle neutron diffraction [5]. We report a comprehensive study of the so-called chiral fraction in MnSi using a newly developed miniature spherical neutron polarimetry device "MiniMuPAD". The temperature dependence and the isotropic decay of the measured chiral fraction are in excellent agreement with the Brazovskii scenario.
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S. A. Brazovskii, Sov. Phys. JETP 41, 85 (1975)
M. Janoschek et al., arXiv:1205.4780 (2012)