Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Correlated Electrons: Quantum-Critical Phenomena - Experiment I
TT 35.5: Vortrag
Dienstag, 1. April 2014, 10:30–10:45, HSZ 204
Frustration and Quantum Criticality in Ni-doped CePdAl — •Veronika Fritsch1, Zita Huesges2, Oliver Stockert2, Christian Taubenheim1, Wolfram Kittler1, Chien-Lung Huang1, Kai Grube1, and Hilbert v. Löhneysen1 — 1Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — 2Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
In heavy-fermion systems, magnetic quantum phase transitions (QPT) usually arise from the competition between RKKY and Kondo interaction. For large Kondo interactions the 4f states hybridize strongly with the conduction electrons, thus suppressing the magnetic ordering temperature to zero. Magnetic frustration is an alternative way to suppress the magnetic order, while keeping the local moments intact. Recently theoretical models were developed discussing additional frustration-induced fluctuations for heavy-fermion metals. We will examine the role of magnetic frustration at the QPT in the heavy fermion system CePdAl, which crystallizes in a hexagonal ZrNiAl-type structure, where the magnetic Ce-ions form a distorted kagomè lattice. The magnetic order, as revealed through previous neutron scattering experiments, is partially frustrated with one third of the Ce-ions not participating the long-range magnetic order. An external magnetic field turns the system toward a Fermi-liquid state. The substitution of Pd by Ni yields a QPT accompanied by non-Fermi-liquid behavior. We will present our recent experiments on single-crystalline CePd1−xNixAl, namely measurements of specific heat, thermal expansion, electrical resistivity and magnetization, as well as neutron scattering experiments.