Berlin 2005 – scientific programme
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TT: Tiefe Temperaturen
TT 35: Correlated Electrons - Quantum Critical Phenomena
TT 35.3: Talk
Wednesday, March 9, 2005, 11:45–12:00, TU H104
Quantum Critical Behavior in Yb1−xLaxRh2Si2 Studied by Low Temperature Resistivity in Magnetic Fields and under High Pressure — •Michael Nicklas, Julia Ferstel, Christoph Geibel, and Frank Steglich — Max-Planck-Institute for Chemical Physics of Solids, Nöthnitzer Str.40, 01187 Dresden
The stoichiometric heavy fermion system YbRh2Si2 is situated close to a quantum critical point (QCP). At zero magnetic field very weak antiferromagnetic order occurs at TN=70 mK. Substitution of Si by larger Ge reduces TN, however, difficulties in sample preparation prevent a complete suppression of TN by Ge-doping. An alternative route to suppress the antiferromagnetic order is the partial substitution of Yb by larger La in Yb1−xLaxRh2Si2.
We present pressure studies of the electrical resistivity of the paramagnetic 5% and 10% La substituted Yb1−xLaxRh2Si2. Applying pressure reduces the unit cell volume again and the system can be tuned through the critical volume. However, substitution of the magnetic ion by non-magnetic La at the Yb-site has more subtle effects and acts not just as chemical pressure on the system.