Heat-induced nanocluster formation in codeposited Ag[sub 1-x]Co[sub x] thin films: Nuclear magnetic resonance study.

[sup 59]Co nuclear magnetic resonance has been used to study the formation of Co nanoclusters in several series of thin-film Ag[sub 1-x]Co[sub x] alloys (0.08<=x<=0.4) prepared by coevaporation and subjected to different heat treatments. Co particles originally formed during the deposition process were found to be single-domain fcc Co clusters, having the shape of truncated octahedra of about 4.5 nm in diameter. Annealing at 200 °C resulted in a size increase to about 7 nm, but after annealing at 350 °C, the particles grew to about 26 nm while remaining single magnetic domain. Upon further annealing, the onset of large, multidomain Co clusters is evidenced. The Co concentration in the original alloy influenced the density of Co particles, but not their size, which was essentially determined by the annealing conditions. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]