Eur. Phys. J. D 24, 101-104 (2003)
https://doi.org/10.1140/epjd/e2003-00147-0

^69,71Ga NMR studies of a superconducting Ga₈₄ cluster compound

¹ Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300RA Leiden, The Netherlands
² Institut für Anorganische Chemie, Universität Karlsruhe, 76128 Karlsruhe, Germany

Corresponding author: ^a bakharev@phys.leidenuniv.nl

Received: 10 September 2002
Published online: 3 July 2003

Abstract

We present ^69,71Ga-NMR experiments on microcrystalline samples of the recently discovered supramolecular compound , which is composed of ligand-coordinated Ga₈₄ metal clusters, packed together in a fully ordered crystalline matrix. The compound is highly conducting and even shows superconductivity below K. Our preliminary results between 10–300 K show a metallic-like behavior: the nuclear spin-lattice relaxation rate follows the Korringa law = 0.36 , but with a relaxation rate approximately three times smaller than in bulk α-Ga metal. No quantum-size effects are observed, the Korringa law being followed down to 10 K, whereas the quantum-gaps for individual clusters should amount to  K. These results therefore suggest a transport process based on intermolecular charge transfer, similar as in alkali-doped fullerenes and silicon-clathrates.