Berlin 2015 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 44: Correlated Electrons: Quantum-Critical Phenomena – Experiments
TT 44.1: Vortrag
Dienstag, 17. März 2015, 14:00–14:15, H 3005
Magnetic structure of CeCu2Ge2 and its implications on filed tuned quantum criticality — •Philipp Geselbracht1, Karin Schmalzl2, Micha Deppe3, Christoph Geibel3, and Astrid Schneidewind4 — 1Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Garching, Germany — 2Jülich Centre for Neutron Science (JCNS) at ILL, Forschungszentrum Jülich GmbH, Grenoble, France — 3Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden, Germany — 4Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Garching, Germany
Recently, the common understanding of quantum criticality (QC) has been challenged for CeCu2Ge2 [1]. An external magnetic field can suppress the magnetic order, regardless of its direction, but only for the field along the a-direction, a quantum critical point could be identified. Such a behavior resembles the situation for QC of an Ising magnet in a transversal magnetic field, as already applied to less complicated model systems [2]. In this model, the field direction relative to the spin direction plays a crucial role. Therefore, we determined the magnetic structure of CeCu2Ge2 on a single crystal by means of polarized neutrons and solution of the magnetic structure. Our results are more thorough as in previous works [3], were the exact direction of the magnetic moments were left unclear. We will then interpret our new findings in analogy to the previous model systems.
[1] PRB 90, 155101 (2014).
[2] PRX 4, 031008 (2014).
[3] PRB 55, 6416-6420 (1997) and references.