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MA: Fachverband Magnetismus
MA 14: Focus Session: Frustrated Magnetism and Local Order (joint session MA/TT)
MA 14.1: Hauptvortrag
Dienstag, 19. März 2024, 09:30–10:00, H 1058
Neutron scattering studies of spin-freezing phenomena at quantum phase transitions — •Christian Pfleiderer — School of Natural Sciences, Department of Physics, Technical University of Munich, D-85748 Garching, Germany — Centre for QuantumEngineering (ZQE), Technical University of Munich, D-85748 Garching, Germany — Heinz Maier-Leibnitz Zentrum (MLZ), Technical University of Munich, D-85748 Garching, Germany — Munich Centre for Quantum Science and Technology (MCQST), Technical University of Munich, D-85748 Garching, Germany
A cornerstone of the statistical and thermal physics of condensed matter systems concerns their energy landscape and the associated ergodicity. Conventional and topologically non-trivial forms of long-range magnetic order represent weak forms of non-ergodicity that allow to explore classical and quantum dynamics, as well as the origin and nature of topological protection. In contrast, strong forms of non- ergodicity related to glassy configurations and freezing transitions permit the comparison of quantum versus thermally driven relaxation as constrained, e.g., by disorder. Combining the results of neutron depolarization, neutron diffraction, and neutron spectroscopy with magnetization and ac susceptibility measurements, similarities and differences of spin freezing phenomena at selected quantum phase transitions will be presented. This includes the putative formation of reentrant spin glass behaviour in Fe1−xCrx, a Kondo cluster glass in CePd1−xRhx, and a spin liquid in HgCr2Se2 under pressure.
Keywords: quantum phase transition; neutron scattering; frustration; spin glass