LOW-ENERGY ION-BEAM-ASSISTED DEPOSITION AND GMR OF GRANULAR MAGNETIC-ALLOYS

Granular Co-Ag and NiFe-Ag thin films were prepared by magnetron sputt ering with low-energy (0-500 eV) ion radiation assisted deposition. Fo r sputter-only films the giant magnetoresistance (GMR) ratio varied wi th composition, with a peak occurring at about 35 at.% magnetic compon ent. The ion beam was found to increase the GMR slightly with increasi ng energy and then progressively decrease it. There was an accompanyin g decrease in film thickness and Ag concentration as the ion beam pref erentially sputtered the Ag. TEM has revealed sputtered films to conta in ordered 10-20 nm spherical particles whilst the ion-beam-assisted f ilms were made up of a network of particles clustered into channels.