Magnetic properties of an individual C-nanoparticle

Recent experimental results on the magnetic properties of an individual cobalt nanoparticle are reported in this paper. Using an improved magnetometry technique based on micro-SQUID devices coupled with an original cluster deposition technique; We have detected the magnetization reversal of a single cobalt nanocluster (3 nm in diameter, approximate to 1000 Go-atoms). The spatial distribution of the switching field has been measured at very low temperature leading to the determination of the magnetization reversal process and the magnetic anisotropy axes and constants characteristic of such nanoparticles. These results are compared to those obtained from macroscopic measurements on cluster assemblies using the Vibrating Sample Magnetometry and X-ray Magnetic Circular Dichroism techniques. Magnetic measurements are complemented with structural studies of the cluster core and surface to understand the origin of magnetic anisotropy in Co-nanoclusters. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.