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TT: Fachverband Tiefe Temperaturen
TT 59: Correlated Electrons: Quantum-Critical Phenomena - Experiments
TT 59.12: Talk
Thursday, March 14, 2013, 18:15–18:30, H6
High pressure transport studies of quantum critical behaviour close to ferromagnetism — •Yang Zou1, Zhuo Feng1,2, Peter Logg1, Sven Friedemann1, Hong En Tan1, and F. Malte Grosche1 — 1Cavendish Laboratory, University of Cambridge, UK — 2Department of Physics, University College London, UK
Metals close to a magnetic quantum critical point offer a comparatively clear and well-defined environment to investigate the breakdown of Landau’s Fermi liquid theory. The low temperature band ferromagnet ZrZn2 violates the predictions of Fermi liquid theory over a wide temperature range [1]. We present new measurements of the electrical resistivity and thermal conductivity as a function of applied magnetic field. These suggest that the temperature scale below which Fermi liquid behaviour is observed rises rapidly with field and reaches 6 K at B=9 T. A different kind of Fermi liquid breakdown is seen in the Kondo lattice ferromagnet CeAgSb2 [e.g. 2]. The ferromagnetic transition temperature TC=9.6 K is sensitive to the application of both pressure and transverse magnetic fields. Therefore, tuning these parameters could be used to access a magnetic quantum phase transition. We present transport measurements under pressure and field tuning, as well as combined measurements of the specific heat and the magnetocaloric effect which provide a comprehensive transport and thermodynamic study of the system.
[1] Smith et al. Nature 455, 7217 (2008)
Araki et al. PRB 68, 024408(2003)