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MA: Fachverband Magnetismus
MA 9: Cooperative Phenomena: Spin Structures and Magnetic Phase Transitions
MA 9.4: Talk
Monday, March 27, 2023, 15:45–16:00, HSZ 401
Magnetocrystalline anisotropies and quantum phase transitions in the cubic chiral magnets Mn1−xFexSi and Mn1−xCoxSi — •Vivek Kumar, Andreas Bauer, Marc Andreas Wilde, and Christian Pfleiderer — Physik-Department, Technische Universität München, D-85748 Garching, Germany
In the archetypical cubic chiral magnet MnSi, an extended regime of topological non-Fermi liquid behavior emerges without quantum criticality as magnetic order is suppressed by means of hydrostatic pressure [1]. Substitutional doping with iron or cobalt also results in the suppression of magnetic order, where quantum critical behavior is masked by the influence of disorder [2]. Recent small-angle neutron scattering studies suggested that in this context magnetocrystalline anisotropies may subtly but decisively influence the magnetic textures, however, no quantitative information was available [3]. Here, we report a study of a series of single crystals of Mn1−xFexSi and Mn1−xCoxSi by means of cantilever torque magnetometry. An analytic description that takes into account the tetrahedral point group of the cubic chiral magnets allows us to quantitatively infer anisotropy constants up to sixth-order in spin-orbit coupling and discuss their evolution as a function of temperature, magnetic field, and dopant concentration x.
[1] Pfleiderer et al., Science 316, 1871 (2007).
[2] Bauer et al., Phys. Rev. B 82, 064409 (2010).
[3] Kindervater et al., Phys. Rev. B 101, 104406 (2020).