Magnetic properties of an individual C-nanoparticle

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