Upper Critical Field of New Oxide Superconductor Bi-Sr-Ca-Cu-O

Abstract

The upper critical field H _c2 of Bi-Sr-Ca-Cu-O superconducting material, with a resistive transition above 100 K, was investigated by observing variations in resistivity with temperature down to 50 K and with magnetic fields up to 12 T. The slope of the critical field, the change in H _c2 with temperature, was -1.5 T/K for the midpoint of the transition. The values of H _c2 at 77 K and 0 K were estimated by extrapolation to be 41 T and 108 T, respectively.