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 solids 1,2 has given rise to intensive research on molecular electronics 3,4. In the course of investigating the properties of a class of anionic metal clusters based on the vanadium oxide systems 5-8, which bear analogy with those of bulk solid material 6, 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 multilayers 9 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 weak 10. The behaviour of this cluster suggests the possibility of applications for molecular-scale switching.