Simple Electroless Synthesis of Cobalt Nanoparticle Chains, Oriented by Externally Applied Magnetic Fields

Abstract The electroless (chemical) deposition of cobalt on palladium-sensitized oxidized silicon wafers produces nanowires and chains made up by nanoparticles. We demonstrate that the application of moderate magnetic fields, provided by permanent magnets, during the growth produces highly oriented cobalt nanowires and nanoparticle chains. By adjusting the magnetic field direction in plane, parallel and crossed cobalt chain patterns are readily accessible. Perpendicular orientation of the field results in rod-like, standing-up chains of nanoparticles. We explain the observed structures with magnetostatic arguments.