Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 38: Correlated Electrons: Spin Systems and Itinerant Magnets 1
TT 38.10: Vortrag
Donnerstag, 29. März 2012, 12:15–12:30, H 3010
On the magnetic phase diagram of B20 compounds inferred from magnetization and ac susceptibility — •Andreas Bauer and Christian Pfleiderer — Physik Department E21, Technische Universität München, D-85747 Garching, Germany
We report comprehensive, simultaneous measurements of the magnetisation, M, and the ac susceptibility, χac, across the magnetic phase diagram of optically float-zoned high-quality single crystals of MnSi, where we explore the importance of the excitation frequency, excitation amplitude, sample shape, and crystallographic orientation. We show that the temperature dependence of the magnetisation of MnSi reported by Kadowaki et al. [1] is connected with a single skyrmion phase. Moreover, our data establishes consistently for all major crystallographic directions a well defined, slightly broadened first order transition at the helical to conical phase boundary, as well as for the skyrmion lattice phase. The same general features are also observed for typical temperature and field scans in Mn1−xFexSi and Fe1−xCoxSi. Taken together, our results question the phase diagram of FeGe reported by Wilhelm et al., which was purely inferred from the ac susceptibility at 1 kHz of a vapour grown single crystal with ill-defined sample shape for a single field direction [2].
K. Kadowaki et al., J. Phys. Soc. Japan, 51, 2433 (1982)
H. Wilhelm et al., PRL 107, 127203 (2011)