XANES STUDY OF THE DEPENDENCE OF THE ITINERANT HOLE DENSITY IN THE SUPERCONDUCTING Hg0.5Bi0.5Sr2Ca1-xRxCu2O7-δ (R=NdandPr) SYSTEM

Abstract

X-ray absorption measurements have been made at the Cu L 3 and O K-edge on ( Hg 0.5 Bi 0.5) Sr 2( Ca 1-x Pr x) Cu 2 O 7-δ (x=0.35,0.50) and ( Hg 0.5 Bi 0.5) Sr 2( Ca 0.65 Nd 0.35)- Cu 2 O 7-δ superconducting systems. Our results clearly indicate that hole density decreases with increase in Pr content. The values of T c for Pr and Nd (x=0.35) systems are the same but the itinerant hole density is found to be larger in the latter case. In view of the fact that the density of holes depends more upon diamagnetic fraction than the T c in these superconducting systems, we can conclude that superconducting properties are different for these two cases.