SUPERPARAMAGNETIC NANOCOMPOSITE OF SILVER IRON-OXIDE BY INERT-GAS CONDENSATION

A superparamagnetic nanocomposite of silver and iron oxide was synthesized by gas condensation. The procedure involved (1) coevaporation of Silver and iron, (2) in situ oxidation of iron particles, (3) in situ compaction, and (4) post-annealing in an inert or an oxidizing atmosphere. The magnetization plots against H/T fell on a single curve from room temperature to 160 K, thereby providing evidence of superparamagnetism. Annealing treatment modifies the effective magnetic moment size and saturation value of magnetization. The present process is a potential synthesis route for magnetic nanocomposites useful for applications such as magnetic refrigeration, recording and permanent magnets.