Dresden 2014 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 79: Correlated Electrons - Poster Session
TT 79.8: Poster
Mittwoch, 2. April 2014, 15:00–19:00, P2
Hidden energy scale in CePdAl — Chien-Lung Huang1, Kai Grube1, •Christian Taubenheim1, Veronika Fritsch1, Sarah Woitschach2, Zita Huesges2, Oliver Stockert2, and Hilbert v. Löhneysen1 — 1Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany — 2Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
CePdAl is a partially geometrically-frustrated heavy-fermion antiferromagnet with a Néel temperature TN = 2.7 K crystallizing in the hexagonal ZrNiAl structure. We measured the thermal expansion αa,c and the magnetostriction λa,c along both crystallographic axes in the temperature range of 0.02 K ≤ T ≤ 10 K and magnetic fields of up to 14 T. From αa,c and λa,c we derive the T - B phase diagram below 1 K. Across the magnetic phase boundaries into the paramagnetic state αa,c/T shows a peak moving to T → 0 at B* = 3.5 T, which is concomitant with maxima in λ(B), entropy S(B), and magnetic susceptibility χ(B). This suggests a possible hidden energy scale in CePdAl, which might be tuned by applying pressure. To this end, we investigated the pressure dependence of the magnetization and performed magnetoresistivity measurements between 1.8 K ≤ T ≤ 10 K and B ≤ 5 T. As a first result the pressure dependence is found to be very weak, since αa and αc have opposite signs. This explains the different values for TN found in literature.