Nuclear Quadrupole Resonance of Cu in High-TcBi–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.