High field properties of ternary metal-molybdenum-sulfides

Measurements of the upper critical fields are presented for ternary metal-molybdenum-sulfides as a function of temperature, T, with dc magnetic fields up to ∼215kG and pulsed fields to ∼500kG. A nearly linear variation of HC2versus T is observed up to the highest dc fields for all the compounds. The materials (nominal composition), Tc(measured); (measured), and HC2(4.2 K) (calculated) for a dirty type II superconductor assuming no paramagnetic limiting are respectively: (a) Pb0.9Mo5.1S6: 11.7 K, 60 kG/K, 390 kG; (b) SnAl0.5Mo4.5S6: 14.2 K, 32 kG/K; 275 kG; (c) SnMo5S6:13.4K, 37kG/K; 290 kG; (d) PbMo5.1S6: 14.4, 60kG/K, 515kG. Pulsed field measurements yield HC2(4.2 K) = 390 kG for (a), 275 kG for (b), 290 kG for (c), and ≃510kG for (d). The PbMo5.1S6has the highest value of HC2measured to date.