Influence of synthesis conditions on the nanostructure of immiscible copper-silver alloy thin films

Far from equilibrium, immiscible nanocrystalline Cu-Ag alloy thin films of nominal composition Cu-30( 5) at.% Ag were deposited by co-sputtering. While films deposited at similar to 300 K exhibit a two-phase mixture of face-centered cubic (fcc) Ag + fcc Cu, those deposited either at similar to 100 K or at low power (similar to 40 W) exhibit an fcc Cu-25 at.% Ag solid solution, excess fcc Ag and small fractions of a metastable hexagonal (4H) Cu-Ag phase. Increasing the sputtering gas pressure leads to phase separation into fcc Cu, fcc Ag and metastable 4H Cu-Ag. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.