PHASE IDENTIFICATION OF A SUPERPARAMAGNETIC IRON-OXIDE SILVER NANOCOMPOSITE/

A nanocomposite, composed of a magnetic iron-oxide dispersed in a silv er matrix was synthesized by inert gas condensation combined with in s itu oxidation and compaction. It was found that the composite exhibits superparamagnetism and that a post annealing treatment modifies the m oments and saturation magnetization. The iron oxide phase giving rise to the magnetism was investigated by Mossbauer and X-ray absorption sp ectroscopies. The magnetic species was identified as gamma-Fe2O3 after the post annealing treatments, whilst Fe and Fe3O4 coexist in the as- prepared loose powder and the as-compacted pellet.