Size Distribution of γ- and α-Fe Complex Clusters in Fe/Cu Granular Film Deposited by Cluster Beam Technique

Abstract

Granular Fe_xCu_100-x films have been produced by a cluster beam (CB) technique. Small angle X-ray scattering (SAXS) measurements indicate that the geometrical size of Fe clusters is about 5, nm in diameter for x=13. Magnetization and magnetoresistance curves between 5 and 300, K can be fitted to the Langevin functions with taking account of the Fe cluster size distribution and an inter-cluster magnetic interaction. The average magnetic cluster size estimated from these analyses is about 1.6, nm (180 atoms) for T≥ 50, K, which is roughly consistent with SAXS observation. However, smaller size distribution of about 0.6, nm (10 atoms) is obtained from the same analysis of the results at T=5, K. This implies a magnetic size-down originated from a magnetic frustration at low temperature.