A superparamagnetic nanocomposite of silver and iron oxide was synthesized by inert 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 160K, providing evidence of superparamagnetism. Annealing treatment modifies the effective magnetic moment size and saturation value of magnetization. The iron oxide phase giving rise to the magnetism was investigated by Mössbauer and X-ray absorption spectroscopies. The magnetic species was identified as γ-Fe
2O
3 after the post annealing treatments, while Fe and Fe
3O
4 coexist in the as-prepared loose powder and the as-compacted pellet. The present process is a potential synthesis route for magnetic nanocomposites useful for applications.
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