Low-temperature properties below 1 K of single crystalline Sr3Ru2O7

We have measured electrical resistivity and specific heat down to 0.2 K with high-quality single crystals of Sr3Ru2O7, the residual resistivity of which is less than 1 μΩ cm. The specific heat coefficient γ was estimated to be 116 mJ/(Ru mol K2). Although a transition to the zero resistance was sometimes observed in the resistivity, no associated transition was observed in the specific heat. We conclude that superconductivity is not intrinsic to Sr3Ru2O7