Magnetic Field-Tuned Quantum Critical Point In Ceausb2

Transport, magnetic, and thermal properties at high magnetic fields (H) and low temperatures (T) of the heavy-fermion compound CeAuSb2 are reported. At H=0 this layered system exhibits antiferromagnetic order below T-N=6 K. Applying B along the interplane direction, leads to a continuous suppression of T-N and a quantum critical point at H-c similar or equal to 5.4 T. Although it exhibits Fermi-liquid behavior within the Neel phase, in the paramagnetic state the fluctuations associated with H-c give rise to unconventional behavior in the resistivity (sublinear in T) and to a T ln T dependence in the magnetic contribution to the specific heat. For H > H-c and low T the electrical resistivity exhibits an unusual T-3 dependence.