Compositional partition in Ag-Nb alloy clusters produced by a plasma-gas-condensation cluster source

Abstract

We have produced Ag-Nb clusters by a facing-target type plasma-gas-condensation cluster source as our first step toward alloy cluster formation. The Ag-Nb clusters have been deposited on substrates and examined by a transmission electron microscope with a nano-beam energy dispersive X-ray analysis. We have obtained Ag-Nb alloy clusters with the sizes range between 5 and 10 nm in diameter. Their chemical compositions are broadly dispersed and partitioned into Ag-rich and Nb-rich ones, being consistent with the immiscible type equilibrium phase diagram. This result suggests that alloy cluster formation is driven by the alloy phase stability.