EFFECT OF Pb AND Sr SUBSTITUTIONS ON IRREVERSIBILITY AND FISHTAIL LINES OF Hg-1223 PHASE: POWDER, CERAMIC AND SINGLE CRYSTAL STUDIES

摘要

HgBa_2Ca_2CujO_y phase (Hg-1223) possess the highest values of critical temperature T_c = 134 K [1], but still does not considered as an attractive candidate for application in high magnetic fields. The main reason attributed to the relatively weak magnetic flux pinning characteristics of this phase. It was shown that irreversibility line (IL) of the Hg-1223, which set the upper limit for application of this compound in the H-T phase space, located between those of Y-123 and Bi,Tl-2212 phases [2], but still lower than that for Tl-1223.