Cu nuclear quadrupole resonance study of Y Ba₂Cu₄O₈ at high pressure

Abstract

We have measured the nuclear quadrupole resonance (NQR) frequencies of 63Cu for both the Cu chain and plane site in Y Ba2Cu4O8 up to 0.7 GPa in the normal and superconducting phase. The results are analysed by taking into account lattice and valence contributions to the electric field gradient at the corresponding Cu site. © 1990.