Regensburg 2013 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 75: Transport: Spintronics and magnetotransport 1 (TT, jointly with HL, MA)
HL 75.10: Vortrag
Donnerstag, 14. März 2013, 12:00–12:15, H18
Investigation of spin transfer torques in Mn1-xFexSi — •Christoph Schnarr, Robert Ritz, Andreas Bauer, Christian Franz, and Christian Pfleiderer — Technische Universität München, Physik-Department E21, D-85748 Garching, Germany
Small angle neutron scattering and Hall effect measurements recently revealed sizeable effects of spin transfer torques in the skyrmion lattice phase of MnSi [1,2]. The associated critical current densities of ∼ 106 A/m2, are exceptionally small and about 5 orders of magnitude smaller than the spin transfer torque observed in conventional systems. The low critical current density is due to a very efficient gyromagnetic coupling exhibited by a topological Hall contribution that arises in the topologically non-trivial magnetic structure of a skyrmion lattice. We report spin transfer torque experiments, measuring the Hall effect in Mn1-xFexSi for a wide range of x, where the topological Hall effect increases by up to a factor of ten characteristic of a much more efficient coupling of the electric currents to the magnetic structure. The dependence of jc on the doping concentration is discussed in view of the increased topological Hall effect as well as the increased pinning by disorder.
[1] F. Jonietz et al., Science 330, 1648-1651 (2010)
T. Schulz et al., Nat Phys 8, 4, 301-304 (2012)