Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 72: Poster Session: Correlated Electrons

TT 72.3: Poster

Mittwoch, 14. März 2018, 15:00–19:00, Poster B

Pressure and field dependent entropy of the heavy-fermion system CePdAl — •Kai Grube¹, Sebastian Kuntz¹, Chien-Lung Huang², Veronika Fritsch³, and Hilbert von Löhneysen^1,4 — ¹Institut für Festkörperphysik, Karlsruher Institut für Technologie, 76021 Karlsruhe, Germany — ²Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States — ³Experimentalphysik VI, Elektronische Korrelationen und Magnetismus, Universität Augsburg, 86159 Augsburg, Germany — ⁴Physikalisches Institut, Karlsruher Institut für Technologie, 76049 Karlsruhe, Germany

In the heavy-fermion metal CePdAl long-range antiferromagnetic order coexists with geometric frustration of one third of the Ce moments. At low temperatures the Kondo effect tends to screen the frustrated moments. We used magnetic fields B to suppress the Kondo screening and studied the magnetic phase diagram and the evolution of the entropy with B and pressure employing thermodynamic probes. We estimated the frustration by introducing a definition of the frustration parameter based on the enhanced entropy, a fundamental feature of frustrated systems. In the field range where the Kondo screening is suppressed the liberated moments tend to destabilize the magnetic order and strongly enhance the frustration.