The Composition and Magnetic Property of Co/Cu Alloy Microwires Prepared Using Meniscus-Confined Electrodeposition: Effect of [Co2+], [Cu2+] Concentration at the Tip of the Meniscus

Abstract

Meniscus-confined electrodeposition (MCED) is an effective and versatile technique for fabrication of alloy structures with precise localization and high controllability. Here, the fabrication of cobalt-copper (Co/Cu) alloy microwires using MCED techniques is reported. Co/Cu microwires with a wide range of compositions (Co9Cu91 to Co100Cu0) and controllable morphology were printed using the co-electrodeposition mode from a single electrolyte. We utilized multiphysics finite element simulation to investigate the influence of electrolyte evaporation and electric field on the concentration distribution of metal ions in the meniscus. The concentration of ions at the substrate interface increases linearly with decreasing humidity and increasing current density, which can be used to fine turn the alloy composition. By further analyzing the alloy composition, we found that the electrodeposition of Cu is diffusion controlled, while Co is mainly electrochemical reaction controlled, as a results of combined action of surface evaporation and reaction dynamics in the meniscus. The prepared alloy wires are polycrystalline, dense and uniform composition distribution. The coercivity and magnetic anisotropy are enhanced by increasing of the copper content in the alloy wires. The high tunability of composition make this alloy a promising material for magnetic micro/nano-electromechanical devices.