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TT: Fachverband Tiefe Temperaturen

TT 19: Correlated Electrons: Quantum-Critical Phenomena

TT 19.8: Vortrag

Dienstag, 26. Februar 2008, 16:00–16:15, H 3010

Low temperature electric transport of Yb(M_xRh_1−x)₂Si₂ M=Co,Ir — •Sven Friedemann, Niels Oeschler, Cornelius Krellner, Christoph Geibel, and Frank Steglich — Max Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, 01187 Dresden, Germany

The heavy-fermion metal YbRh₂Si₂ exhibits pronounced non-Fermi liquid behavior due to its vicinity to a quantum critical point (QCP). By applying small magnetic fields, YbRh₂Si₂ is driven from an antiferromagnetic (AFM) state to the QCP. At the critical field a second energy scale T^⋆ vanishes that manifests itself as a crossover in transport and thermodynamic properties, e.g. magnetoresistance. Doping Co (Ir) on the Rh side acts as chemical pressure enhancing (decreasing) the AFM ordering temperature and the critical field of the ordered phase. We here report low temperature resistivity and magnetoresistance measurements on x=3,7% Co and x=6% Ir doped single crystals. The data are compared with that of the undoped system. Although the ordering temperature is observed to change as expected we find the features associated with T^⋆ to be robust upon doping.