Encapsulation-induced stabilization of dimensionally restricted metallic alloy wires

Compositionally modulated CuNiFe alloys wires were grown on sapphire substrates in two dimensionally restricted configurations, the first by dewetting thin films on crystallographically faceted free surfaces and the second by enclosure within lithographically sculpted cavities. Samples were annealed at elevated temperature to promote evolution towards chemical and morphological equilibrium. Surface wires of limited length resulted from the break-up of thin films along the long axes of substrate facets. Encapsulated wires oriented along specific crystallographic directions developed stable low energy facets along their lengths and resisted both dewetting and Rayleigh instabilities, enabling fabrication of stable, oriented, modulated (Cu/NiFe) structures.