The Irreversibility Line of (Bi, Pb)2Sr2Ca2Cu3O10 Determined By Dc Magnetization

Abstract

The irreversibility line, H(T), of c-axis aligned Bil. 65Pb0. 35Sr2Ca2Cu3O10 is analyzed based on dc magnetization measurements for fields up to 50 kOe. Its temperature dependence is found to depend strongly on the criterion used to determine irreversibility. Using sensitivity criteria of 5, 15 and 25 x 10–5 emu, the low field data fit H* ~H0 (1-T/Tc)γ with yo= 2.3 - 2.6 and Ho ~1.8 X 104 emu. Using fitted curves, the irreversibility line follows this equation over the entire field range with Y= 3.2 and H0 ~35 x 104 emu. © 1991 IEEE