We report β-detected nuclear magnetic resonance of ultra-dilute 8Li+ implanted in highly oriented pyrolytic graphite (HOPG). The absence of motional narrowing and diffusional spin-lattice relaxation implies Li+ is not appreciably mobile up to 400 K, in sharp contrast to the highly lithiated stage compounds. However, the relaxation is remarkably fast and persists down to cryogenic temperatures. Ruling out extrinsic paramagnetic impurities and intrinsic ferromagnetism, we conclude the relaxation is due to paramagnetic centers correlated with implantation. While the resulting effects are not consistent with a Kondo impurity, they also differ from free paramagnetic centers, and we suggest that a resonant scattering approach may account for much of the observed phenomenology.
Cite
@article{arxiv.2301.07821,
title = {Ion-Implanted $^8$Li Nuclear Magnetic Resonance in Highly Oriented Pyrolytic Graphite},
author = {John O. Ticknor and Jonah R. Adelman and Aris Chatzichristos and Martin H. Dehn and Luca Egoriti and Derek Fujimoto and Victoria L. Karner and Robert F. Kiefl and C. D. Philip Levy and Ruohong Li and Ryan M. L. McFadden and Gerald D. Morris and Mohamed Oudah and Monika Stachura and Edward Thoeng and W. Andrew MacFarlane},
journal= {arXiv preprint arXiv:2301.07821},
year = {2023}
}