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

A superparamagnetic nanocomposite of silver and iron oxide was synthes ized 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 atmosph ere. The magnetization plots against H/T fell on a single curve from r oom temperature to 160 K, thereby providing evidence of superparamagne tism. Annealing treatment modifies the effective magnetic moment size and saturation value of magnetization. The present process is a potent ial synthesis route for magnetic nanocomposites useful for application s such as magnetic refrigeration, recording and permanent magnets.