Low-temperature specific heat of YbRh2Si2

Low-temperature specific heat measurements on single crystalline YbRh2Si2 in small magnetic fields are reported. The phase diagram around its quantum critical point is deduced which confirms the antiferromagnetic and the Fermi-liquid region as deduced from transport measurements. Furthermore, the specific heat reveals that the additional crossover line at T* which was recently observed in field-dependent transport and thermodynamic measurements is independent of the Fermi liquid regime. (C) 2007 Elsevier B.V. All rights reserved.