Superconductivity of Pb-Bi alloys under high pressure

Abstract

The superconducting behavior of Pb 0 . 4 -Bi 0 . 6 alloys was studied. ~nder pressure to 20 kbat using piston-cylinder devices with a clamp technique:Nearly hydrostatic conditions were achieved by use of powdered Teflon or a 1:1 mixture of isoamyl alcohol and pentane as pressure transmitting media, and a Sn manometer• was.employed to determine the pressure directly at cryogenic temperatures. The superconducting transitions were detected by ac susceptibi 1 ity measuremen.ts.At low pressures, these alloys are a.mixture of two different phases: a) the rhombohedral phase which is nearly pure .Bi, and~) the hcp phase