Superconductivity in U–Pt system with low Pt concentrations (≤15 at.%)

Highlights: • U-15 at.% Pt alloy prepared by splat-cooling technique stabilizes in the cubic γ-U structure. • U-15 at.% Pt splats become superconducting below 1.1 K. • The sharpest jump in electrical resistivity was observed at T_c= 0.61 K for splat consisting mostly γ-U phase. • A broad maximum was observed around T_c in the specific heat. - Abstract: We report the study of superconductivity in U–Pt alloys with Pt alloying concentration in the range of 0 – 15 at.%. We have succeed to retain the high-temperature (cubic) γ-U phase down to low temperatures in U-15 at.% Pt alloy by means of splat-cooling technique with a cooling rate better than 10⁶ K/s (U-15 at.% Pt splat). The superconducting phase transitions are revealed below 1 K from electrical resistivity and specific heat measurements in applied magnetic fields for all investigated splat-cooled alloys. We underline the difference in the superconducting transition in U-15at.% Pt splats with that in the as-cast bulk and annealed bulk sample with the same Pt concentration.