From Co/Pt multilayered nanowires to Co-Pt alloy nanowires: structural and magnetic evolutions with annealing temperatures

Co/Pt multilayered (ML) nanowires were prepared by template-assisted pulsed electrodeposition. Structural and magnetic evolutions of the deposited ML nanowires upon annealing in a hydrogen atmosphere were studied by transmission electron microscopy, x-ray diffractometry and magnetometry. It was found that the deposited nanowires undergo a morphological change from multilayers to continuous and dense alloy wires with increasing annealing temperature. The fraction and the grain size of the f.c.t. Co-Pt ordered phase were also found to increase with annealing temperature, giving rise to a markedly enhanced magnetic performance of the annealed nanowires. Our study provides an alternative approach, apart from direct template-based electrodeposition, to the fabrication of Co-Pt alloy nanowires with tunable structures and magnetic properties.