Study of the superconducting state of ternary molybdenum sulphides

The properties of the superconducting state of massive samples of ternary molybdenum sulphides containing copper, tin or lead are investigated. The highest values of all three critical parameters Tsub(c), Hsub(c2) and Jsub(c) are found in the lead-containing compounds. Variation of the anneling temperature from 720 to 1120 deg C with the duration of annealing kept constant (24 h) results in an alteration of the critical current density in Pbsub(1,.2)Mosub(3. 4)Ssub(8) specimens by more than an order of magnitude whereas the other critical parameters change by less than 40%. The peak value of the critical current density Jsub(c)(140 kOe; 1.7 K) = 3.5x108 A/m2 is attained at annealing temperatures of 920 deg C. The relation between the shape of the Jsub(c)(H, T=const) curves and the decay rate of the critical current in hollow cylindrical specimens is analyzed