The first cobalt molecule to function as a single-molecule magnet, [Co4(hmp)4(MeOH)4Cl4], where hmp- is the anion of hydroxymethylpyridine, is reported. The core of the molecule consists of four Co(II) cations and four hmp- oxygen atoms ions at the corners of a cube. Variable-field and variable-temperature magnetization data have been analyzed to establish that the molecule has a S=6 ground state with considerable negative magnetoanisotropy. Single-ion zero-field interactions (DSz2) at each cobalt ion are the origin of the negative magnetoanisotropy. A single-crystal of the compound was studied by means of a micro-SQUID magnetometer in the range of 0.040-1.0K. Hysteresis was found in the magnetization versus magnetic field response of this single crystal. It is concluded that this is the first cobalt molecule to function as a single-molecule magnet.
@article{arxiv.cond-mat/0109219,
title = {The First Cobalt Single-Molecule Magnet},
author = {En-Che Yang and David N Hendrickson and Wolfgang Wernsdorfer and Motohiro Nakano and Roger Sommer and Arnold L Rheingold and Marisol Ledezma-Gairaud and George Christou},
journal= {arXiv preprint arXiv:cond-mat/0109219},
year = {2019}
}