Tuning the Composition of Alloy Nanoparticles Through Laser Mixing: The Role of Surface Plasmon Resonance

We report the formation of AuxNi1-x alloy nanoparticles obtained by pulsed laser irradiation of Au and Ni@NiO colloidal mixtures. Structural characterization performed through X-Ray Diffraction and Transmission Electron Microscopy coupled with Energy Dispersive X-Ray Spectroscopy has shown a correlation between the final alloy composition and the different Au/Ni@NiO ratio in the irradiated mixture.Supported by theoretical calculations, we propose as possible mechanism for the formation of the alloy structures a temperature increasing and a subsequent melting of the structures, driven by the excitation of gold surface plasmon resonances. Optical and magnetic characterization confirms a coexistence of the plasmonic and magnetic behaviors in the hybrid systems.