Granular Alloy Film Synthesis Using Ionized Cluster Beam Deposition

Abstract

This thesis involves film growth and characterization, aerosol and gas flow dynamics, ion beam optics, and the production of nanoclusters and their magnetic behavior. Films are grown by simultaneous deposition of ionized nanoclusters from a beam and of atoms from an evaporation source. The resultant films are of granular structure; that is, they have clusters of nanometer size embedded in a matrix. The potential and advantages of this method in creating a diverse array of microstructures is explored. As a first application, magnetic clusters are embedded in a non-magnetic matrix material, and the magnetic properties are measured as a function of microstructure. Granular alloys of this form are known to exhibit giant magnetoresistance. Due to its versatility, this film growth technique enables numerous further experiments in small particle behavior, cluster-surface interactions, and granular film properties.