Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 8: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 8.2: Talk
Monday, February 25, 2008, 14:15–14:30, H 0104
Magnetic phase diagram of MnSi revisited — •Florian Jonietz1, Sebastian Mühlbauer1,2, Christian Pfleiderer1, Achim Rosch3, Rembert Duine4, Andreas Neubauer1, Stefan Legl1, Robert Georgii1,2, 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 — 3Institute of Theoretical Physics, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany — 4Institute for Theoretical Physics, Department of Physics and Astronomy, Utrecht University, 3584 CE Utrecht, The Netherlands
The lack of inversion symmetry in the crystal structure of the itinerant-electron magnet MnSi results in weak Dzyaloshinsky-Moriya interactions, that stabilize a long-wavelength spin spiral (λ∼ 190 Å) in the magnetically ordered state. Motivated by recent neutron scattering studies of the magnetic phase diagram at high pressures we have revisited the magnetic phase diagram at ambient pressure. We report the results of extensive measurements of the AC susceptibility and small angle neutron scattering of the magnetic order of MnSi as function of temperature, magnetic field and electric current. In our study we focus in particular on the stability of the A-phase, a small phase pocket, where the helical order spontaneously aligns perpendicular to the direction of an applied magnetic field.