Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: Correlated Electrons: Heavy Fermions
TT 3.5: Vortrag
Montag, 26. März 2012, 10:30–10:45, H 3005
Resistivity, specific heat, and pressure dependent magnetization of multiple-transition antiferromagnet CeAu2Ge2 — •Chien-Lung Huang1,2, Veronika Fritsch1, Wolfram Kittler1, and Hilbert von Löhneysen1,2 — 1Karlsruher Institut für Technologie, Physikalisches Institut, 76031 Karlsruhe, Germany — 2Karlsruher Institut für Technologie, Institut für Festkörperphysik, 76021 Karlsruhe, Germany
The resistivity and specific heat of a CeAu2Ge2 single crystal grown from Au-Ge flux were measured between 1.8 and 200 K. Two transitions were observed in the specific heat at 11.5 and 14.5 K, confirming our recent susceptibility results[1]. We observe three field-induced transitions in the magnetoresistance measured at 1.6 K in accordance with the B−T phase diagram constructed from magnetization. In addition, we have measured the magnetization under pressure. The antiferromagnetic transition temperature TN is linearly enhanced by pressure with a small rate of 0.067 K/kbar, which suggests that, if attributed to a pure volume effect, this compound is close to the maximum transition temperature of the Doniach phase diagram. The transition fields BM between the field-induced phases increase linearly upon applying pressure. The comparable Grüneisen parameters of TN and BM indicate that the energy scale depending on the sample’s volume is determined by the antiferromagnetic correlations.
V. Fritsch, P. Pfundstein, P. Schweiss, E. Kampert, B. Pilawa, and H. v. Löhneysen, Phys. Rev. B 84, 104446 (2011).