Layered magnetic structure of a metal cluster ion

THE ability of molecular materials to perform many of the optical, electronic and magnetic functions traditionally associated with extended two- and three-dimensional inorganic solids1,2 has given rise to intensive research on molecular electronics3,4. In the course of investigating the properties of a class of anionic metal clusters based on the vanadium oxide systems5–8, which bear analogy with those of bulk solid materials6, we have encountered unusual magnetic behaviour in a finite molecular system. A cluster containing 15 paramagnetic vanadium atoms consists of three distinct layers in each of which the magnetization shows a distinct temperature dependence. Analogous behaviour in bulk systems can be found in magnetic multilayers9 and also in copper oxide superconductors, where copper layers with strong antiferromagnetic coupling are separated by layers of rare-earth ions in which the coupling is very weak10. The behaviour of this cluster suggests the possibility of applications for molecular-scale switching.