Guided self-assembly growth of epitaxial Co dots on lithographically pattered Ru single crystals

Epitaxial Co islands were grown onto lithographically etched Ru(0 0 0 1) substrate at 350°C and characterized ex situ with atomic force microscopy, magnetic force microscopy, and magneto-optical Kerr effect. On 100-nm deep, 6×6 μm2 etched squares, the submicron Co islands tend to decorate the edges. In contrast, on shallow patterns of 5-nm deep and 750-nm wide lines, no preferred island location was observed. The islands tend to elongate into stripes and fine wires when the etched lines are along high-symmetry directions. All patterns induce an in-plane easy axis along the lithographic pattern edges.