Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 3: Correlated Electrons: Quantum-Critical Phenomena
TT 3.1: Vortrag
Montag, 27. März 2006, 09:30–09:45, HSZ 301
Smeared Ferromagnetic Quantum Phase Transition in CePd1−xRhx — •Tanja Westerkamp, Robert Küchler, Adam Pikul, Nubia Caroca-Canales, Micha Deppe, Philipp Gegenwart, Julian Sereni, Christoph Geibel, and Frank Steglich — Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden
Quantum phase transitions in Ce-based systems are presently a subject of strong interest. While there exists a number of compounds showing an antiferromagnetic quantum critical point (QCP), appropriate candidates for the study of the disappearance of a ferromagnetic (FM) state are very scarce. Theories favor a first-order transition in pure systems, while disorder might lead to a continuous second order QCP. In this respect the alloy CePd1−xRhx might be interesting, because it evolves from a FM Ce3+ state at x=0 to a non-magnetic, valence fluctuating state at x=1. A detailed investigation of this system by means of ac-susceptibility and specific heat at T≥ 0.4 K as well as thermal expansion at T≥ 0.1 K suggests a continuous suppression of the FM order. However, TC(x) shows an extended tale and the Grüneisen-ratio analysis raises doubts on a well defined QCP. Here, we report ac-susceptibility measurements down to very low temperatures T≥ 0.02 K at concentrations in the tale region of the phase diagram which characterize the nature of the quantum phase transition in this system.