High field properties of SnMo6S8and PbMo6S8ribbons prepared using a vapor transport technique

Superconducting ribbons of SnMo
6
S
8
and PbMo
6
S
8
have been produced using a one step vapor transport technique. In this process Sn or Pb vapor and H
2
S gas react at the surface of a Mo substrate at elevated temperatures to form a uniform coating of Chevrel phase. SEM micrographs show the film on the ribbons to be composed of small (
\lsim 0.5 \mu
m) single-crystal rhombohedra of Chevrel phase. Critical currents for the SnMo
6
S
8
ribbons are similar to that achieved in PbMo
6
S
8
by other techniques (
\sim 1 \times 10^{4}
A/cm
²
at 19 T and 4.2 K). The performance of our PbMo
6
S
8
is severely degraded. An explanation for this is based on larger intrinsic strain effects in the PbMo
6
S
8
.