Critical currents in Pb/sub 1.2-x/Sn/sub x/Mo/sub 6/S/sub 8/ wires

Increased critical current densities J/sub c/ up to 2*10/sup 4/ A/cm/sup 2/ at 4.2 K and 20 T were found for quaternary Chevrel-phase Pb/sub 1.2-x/Sn/sub x/Mo/sub 6/S/sub 8/ wires. Compared to the ternary compounds, the composition was varied over the whole mixing range, and the change of the crystal structure parameters T/sub c/ and J/sub c/ was analyzed and discussed with respect to the observed J/sub c/ enhancement. These results were obtained for different wire preparation techniques using unreacted or HIP (hot isostatically pressed) prereacted starting materials, but always the same current-stabilized (Cu) and steel-reinforced wire configuration. A very good reproducibility of the J/sub c/ values indicates homogeneous material properties of the filaments and a uniform wire cross section.