Cobalt single-molecule magnet

A cobalt molecule that functions as a single-molecule magnet, [Co-4(hmp)(4)(MeOH)(4)Cl-4], where hmp(-) is the anion of hydroxymethylpyridine, is reported. The core of the molecule consists of four Co(II) cations and four hmp(-) oxygen atom 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-superconducting quantum interference device magnetometer in the range of 0.040-1.0 K. Hysteresis was found in the magnetization versus magnetic field response of this single crystal. (C) 2002 American Institute of Physics.