Variation of the Ratio Hc3/Hc2 in the Immediate Vicinity of Tc

Abstract

We have measured the ratio Hc3Hc2 for tin-rich Sn-In alloys and for indium-rich In-Bi alloys in the immediate vicinity of Tc. For the Sn-In system this ratio decreases as Tc is approached. Similar behavior has been recently reported by Ostenson and Finnemore for pure Nb. The In-Bi alloys, however, show a marked increase in Hc3Hc2 as the critical temperature is approached.