Templated assembly of Co-Pt nanopartides via thermal and laser-induced dewetting of bilayer metal films

摘要

Templated dewetting of a Co/Pt metal bilayer film on a topographic substrate was used to assemble arrays of Co-Pt alloy nanopartides, with highly uniform particle size, shape and notably composition compared to nanopartides formed on an untemplated substrate. Solid-state and liquid-state dewetting processes, using furnace annealing and laser irradiation respectively, were compared. Liquid state dewetting produced more uniform, conformal nanopartides but they had a polycrystalline disordered fcc structure and relatively low magnetic coercivity. In contrast, solid state dewetting enabled formation of magnetically hard, ordered L10 Co-Pt single-crystal particles with coercivity >12 kOe. Furnace annealing converted the nanopartides formed by liquid state dewetting into the L10 phase.