Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: PhD symposium of the Division of Magnetism and the jDPG 2015: Quantum Phase Transitions: Emergent phenomena beyond elementary excitations

MA 18.15: Poster

Dienstag, 17. März 2015, 16:15–16:30, EB 301

Identification of a Brazovskii quantum phase transition in the Chiral Magnet MnSi — •Jonas Kindervater¹, Stefan Ernst¹, Andreas Bauer¹, Wolfgang Häußler^1,2, Nicolas Martin^1,2,3, Peter Böni¹, Markus Garst⁴, and Christian Pfleiderer¹ — ¹Physik-Department, Technische Universität München, Germany — ²Heinz Maier-Leibnitz Zentrum, Technische Universität München, Germany — ³CEA Saclay, DSM/IRAMIS/Laboratoire Leon Brillouin, France — ⁴Institute for Theoretical Physics, Universität zu Köln, Germany

In the chiral magnet MnSi the transition into the ordered phase is driven to first-order due to strongly interacting fluctuations, which can be explained within the framework of the Brazovskii scenario [1]. We report a small angle neutron scattering and high resolution neutron spin echo spectroscopy study on the quantum phase transition in Mn_1−xFe_xSi. Upon suppressing the helimagnetic order by iron doping a putative quantum phase transitions is observed [2]. According to theory [3], a possible Brazovskii quantum phase transition might thereby be realized either as a first- or second-order transition or, alternatively, as a tricritical point. Our study gives insight in the precise nature of the strongly interacting chiral fluctuations and the nature of the quantum phase transitions realized in Mn_1−xFe_xSi.

[1] M. Janoschek et al., PRB 87, 134407 (2013); [2] A. Bauer et al., PRB 82, 064404 (2010); [3] J. Schmalian and M. Turlakov, PRL 93, 036405 (2004)