MAGNETIC CLUSTERS IN MOLECULAR-BEAMS, METALS, AND SEMICONDUCTORS

The evolution of magnetic order from the microscopic to the macroscopi c regime may be studied with the use of nanometer-scale clusters. A va riety of new techniques can be employed to control the size of the mag netic clusters from the atomic level. Molecular beams are used to cons truct and measure the magnetic properties of isolated metallic cluster s. Superparamagnetic metallic particles embedded in a metal exhibit dr amatic field-dependent changes in electrical conduction, providing a m easure of spin-dependent scattering. Related efforts in semiconductor hosts with the use of ion implantation have generated room-temperature ferromagnetic clusters that can be directly imaged by magnetic force microscopy.