Electrochemical growth of Co nanodots on patterned Si substrates

A silicon substrate, prestructured by a focused ion beam, is used as a nano-electrode template to perform a selective electrodeposition of cobalt nanodots. It is found that the shape of the magnetic nanostructures determines to a large extent their magnetic properties. Using magnetic force microscopy, a transition from in-plane to out-of-plane single domain magnetization is observed when the diameter of the 400nm height dots is reduced from 400 to 200nm. Additional ferromagnetic resonance measurements confirm that the magnetic anisotropy is imposed mainly by the shape of the cylindrical dots.