Dresden 2011 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 4: CE: Quantum-Critical Phenomena 1
TT 4.3: Talk
Monday, March 14, 2011, 11:00–11:15, HSZ 201
Neutron spin echo measurements of magnetic fluctuations in helical Mn1−xFexSi — •Alexander Tischendorf1, Wolfgang Häußler1,2, Andreas Bauer1, Peter Böni1, and Christian Pfleiderer1 — 1Technische Universität München, Physik Department E21, 85748 Garching, Germany — 2Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM-II), 85748 Garching, Germany
Manganese silicide (MnSi) is a 3d intermetallic compound that crystallizes in the cubic B20 structure. In the absence of an applied magnetic field and for temperatures below Tc=29.5 K MnSi displays a long-period helimagnetic state with a wavelength of approximately 180 Å. Under substitutional doping with Fe, the helimagnetic transition temperature decreases and terminates in a set of complex quantum phase transitions (QPT) [1]. We have studied the line width of the spin fluctuations in Mn1−xFexSi by means of neutron spin echo measurements. The high energy resolution and the small angle scattering set up of the spin echo instrument RESEDA at the Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) thereby offered an ideal parameter range, that is not accessable in conventional triple-axes measurements. Our results will be discussed, in the context of the spin-fluctuation theory of weakly magnetic itinerant-electron compounds, which allows the identification of anomalous behavior at QPTs.
A. Bauer et al., Phys. Rev. B 82, 064404 (2010)