2009/04/20 by C. Krellner, Stefanie Hartmann, S. Hartmann +7 · 1 citation
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.102.196402
published as Phys. Rev. Lett. 102, 196402 (2009) · Accepted for PRL
arxiv created 2009/04/20 · openalex publication_date 2009/05/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We report on precise low-temperature specific-heat measurements, C(T), of YbRh2Si2 in the vicinity of the antiferromagnetic phase transition on a single crystal of superior quality (residual resistivity ratio of \ensuremath∼150). We observe a very sharp peak at TN=72 mK with absolute values as high as C/T=8 J/mol K2. A detailed analysis of the critical exponent \ensuremathα around TN reveals \ensuremathα=0.38 which differs significantly from those of the conventional universality classes in the Ginzburg-Landau theory, where \ensuremathα\ensuremath≤0.11. Thermal-expansion measurements corroborate this large positive critical exponent. These results provide insight into the nature of the critical magnetic fluctuations at a temperature-driven phase transition close to a quantum critical point.