Pressure dependence of superconductivity in (SN)x

The pressure dependence of the superconducting transition temperature Tc of (SN)x and the upper critical magnetic field Hc2 in various crystallographic directions up to 9.5 kbar are reported. At pressure below 8 kbar Tc increases linearly at a rate 35 mK/kbar. Above 8 kbar a significant change occurs and by 9.5 kbar Tc has decreased to near its zero-pressure value. The increase in Tc and the behavior of Hc2 under pressure favor the interpretation that the superconducting properties of (SN)x result from a collection of weakly coupled fibers of diameter ≤ 100. Nevertheless, the anisotropy observed with magnetic fields perpendicular to the fiber axis agrees with the intrinsic anisotropy determined from the (SN)x band structure. © 1978 The American Physical Society.