Non-Fermi-liquid behavior in single-crystal CaRuO3: Comparison to ferromagnetic SrRuO3

We report calorimetric, magnetic and electric transport properties of single-crystal CaRuO3 and SrRuO3 as a function of temperature T and applied magnetic field B . We find that CaRuO3 is a non-Fermi-liquid metal near a magnetic instability, as characterized by the following properties: (1) the heat capacity C ( T , B ) ∼ − T log T is readily enhanced in low applied fields, and exhibits a Schottky peak at 2.3 K that exhibits field dependence when T is reduced; (2) the magnetic susceptibility diverges as T − γ at low temperatures with 1 / 2 < γ < 1 , depending on the applied field; and (3) the electrical resistivity exhibits a T 3 / 2 dependence over the range 1.7 < T < 24 K . No Shubnikov–de Haas oscillations are discerned at T = 0.65 K for applied fields up to 45 T. These properties, which sharply contrast those of the itinerant ferromagnet SrRuO3, indicate CaRuO3 is a rare example of a stoichiometric oxide compound that exhibits non-Fermi-liquid behavior near a quantum critical point.