Study of the structure and stability of cobalt nanoparticles for ferrofluidic applications

Preparation of functional magnetic nanocomposites and hybrid materials: recent progress and future directions

The aim of this article is to provide an overview of current research activities on functional, magnetic nanocomposite materials. After a brief introduction to general strategies for the synthesis of superparamagnetic nanoparticles (NPs), different concepts and state-of-the-art solution chemical methods for their integration into various types of functional, magnetic nanocomposite materials will be reviewed. The focus is on functional materials which are based on discrete magnetic NPs, including multicomponent nanostructures, colloidal nanocrystals, matrix-dispersed composite materials and mesoscaled particles. The review further outlines the magnetic, structural, and surface properties of the materials with regard to application.

Production and Characterisation of Ferromagnetic Nanoscale Metal Powders Produced by Laser Evaporation

Ferromagnetic metallic nanoscale particles were produced by laser evaporation of Co, Fe and Fe3Al targets with vapour condensation in nitrogen, argon or air. The composition and structure of the nanoscale powders were investigated by XRD and XAS. The Fe and Fe3Al powders condensed in nitrogen or argon consist mainly of the same phase as the targets. Small amounts of various oxides were found too. Condensation in air yields pure oxide nanopowders without metallic phases. From Co targets nanoscale particles with both fcc and hcp structure are obtained. With increasing aggregation gas pressure the mean diameter of the powders increases, leading to a higher saturation magnetisation of the coarser powders. The oxidation stability of the powders can be attributed to oxygen layers on the particles which were found to be 1–2 nm thick.