PERMALLOY NANOPARTICLES GENERATED BY LASER-ABLATION

We describe a new method for producing ultrafine magnetic particles th at employs pulsed-laser particle ablation. Pulsed-laser radiation with wavelength of 248 nm was used to ablate 1 to 10 mu m diameter permall oy microparticles under normal atmospheric conditions. The ejected nan oparticles were collected on silicon substrates for further analysis. Scanning electron micrographs of the samples were analyzed by computer aided image processing to determine the effect of laser fluence on th e particle size distribution. Results showed that mean particle diamet ers were in the range from 60 to 90 nm, and that the particle size dis tributions were closely log-normal.