Low-temperature specific heat and thermal conductivity of superconductingV3Si

We have measured the thermal conductivity of two samples of polycrystalline ${\mathrm{V}}_3$Si in the temperature range $\sim 0.08<T<\mathrm{} \sim 70$ K and the specific heat of one of two samples in the range $0.076<T<\mathrm{}1.25\mathrm{}$ K. A linear $T$ term in the specific heat and a strong $T^2$ component in the thermal conductivity are observed below ∼ 1 K. Second phase inclusions of ${\mathrm{V}}_5$ ${\mathrm{Si}}_3$ in one sample and V(71.4 at.%)-Si(28.6 at.%) in the other are identified through their x-ray fluorescence spectra. Arguments that the inclusions are not superconducting above the lowest temperature of the present measurements are given. The amount of the normal inclusions is shown to be sufficient to account for the observed non-Debye thermal behaviors below ∼ 1 K.