We derived a simple reduced form from the exact solution of the mixed magnetic and quadrupolar nuclear spin--lattice relaxation function at the central transition line of a quadrupole-split NMR spectrum for the nuclear spin I = 3/2. The reduced form of the exact solution could be extended to include inhomogeneous relaxation effects. From the application of the reduced form to the 63Cu nuclear spin--lattice relaxation curves in the high-Tc superconductors of 63Cu-enriched triple-layer HgBa2Ca2Cu3O8+δ, we estimated the predominant magnetic relaxation rate 63WM and the upper limit of a weak nuclear electric quadrupole spin--lattice relaxation rate 63WQ.
@article{arxiv.2409.08408,
title = {Quest for nuclear quadrupole relaxation in HgCa$_{2}$Ba$_{2}$Cu$_{3}$O$_{8+\delta}$},
author = {Yutaka Itoh and Akihiro Ogawa and Seiji Adachi},
journal= {arXiv preprint arXiv:2409.08408},
year = {2024}
}