Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 41: Correlated Electrons: Quantum-Critical Phenomena

TT 41.6: Vortrag

Mittwoch, 22. März 2017, 10:45–11:00, HSZ 204

Magnetic and structural phase transitions in CeCu_6−xAu_x — •Sebastian Kuntz¹, Kai Grube¹, Lothar Pintschovius¹, Frank Weber¹, Peter Schweiss¹, Oliver Stockert², Veronika Fritsch³, Sebastian Bachus³, Yasuyuki Shimura³, Philipp Gegenwart³, and Hilbert von Löhneysen^1,4 — ¹Institut für Festkörperphysik, Karlsruher Institut für Technologie, D-76021 Karlsruhe, Germany — ²Max-Planck-Institut für Chemische Physik fester Stoffe, D-01187 Dresden, Germany — ³Experimentalphysik VI, Center for Electronic Correlations and Magnetism, Augsburg University, 86159 Augsburg, Germany — ⁴Physikalisches Institut, Karlsruher Institut für Technologie, D-76049 Karlsruhe, Germany

The heavy-fermion compound CeCu_6−xAu_x is a model system for unconventional quantum criticality. At small Au contents CeCu_6−xAu_x reveals a structural transition from an orthorhombic to a monoclinic crystal symmetry while at higher x an antiferromagnetic phase appears. To shed light on the interplay between quantum critical magnetic and structural fluctuations we performed neutron scattering experiments and thermodynamic measurements on samples with varying Au concentration between x = 0 and 0.3. The application of hydrostatic and chemical pressure allows to separate the magnetic from the structural transition and demonstrates that the unconventional quantum criticality is based on the magnetic fluctuations and not influenced by the monoclinic distortion.