Nuclear Quadrupole Resonance of Cu in High-<i>T</i>_cBi–Pb–Sr–Ca–Cu–O

Abstract

Nuclear quadrupole resonance (NQR) signals of Cu have been discovered in the high- T c superconducting oxide Bi–Pb–Sr–Ca–Cu–O with T c =109 K. It has been observed that there are two Cu sites with a different quadrupole coupling. The temperature dependence of the nuclear relaxation rate, 1/ T 1 , was similar to that of the CuO 2 plane in YBa 2 Cu 3 O 7 . It is found that the 1/ T 1 for the Cu site demonstrates the reflection of the strong Cu-d spin correlation.