Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 7: Korrelierte Elektronen: Schwere Fermionen

TT 7.6: Vortrag

Montag, 8. März 2004, 16:00–16:15, H19

Quantum Critical Behavior in Yb_1−xLa_xRh₂Si₂ Studied by Low Temperature Resistivity and Specific Heat — •Franziska Weickert, Teodora Rus, Julia Ferstl, Philipp Gegenwart, Christoph Geibel, and Frank Steglich — Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Str.40, 01187 Dresden

The Heavy Fermion System YbRh₂Si₂ is a very suitable compound to study non Fermi liquid properties near a Quantum Critical Point (QCP). At zero magnetic field very weak antiferromagnetic order occurs at 70 mK. A tiny 0.15% volume expansion due to a substitution of nominally 5 % of Si by larger Ge reduces T_N to 20 mK. Difficulties in sample preperation prevent a complete suppression of T_N by Ge-doping.

An alternative and successful route to tune the system through the zero-field QCP is the partial substitution of Yb by larger La in Yb_1−xLa_xRh₂Si₂.

Here we report low temperature resistivity and specific heat measurements on x = 0.05 and 0.1 single crystals, which show the complete suppression of AF order.