Fabrication of Cobalt Magnetic Nanostructures Using Atomic Force Microscope Lithography

Abstract

Cobalt nanopatterns are promising assemblies for patterned magnetic storage applications. The fabrication of cobalt magnetic nanostructures on n-tridecylamine·hydrochloride (TDA·HCl) selfassembled monolayer (SAM) modified silicon surfaces using direct writing atomic force microscope (AFM) lithography for localized electrochemical reduction of cobalt ions was demonstrated. The ions were reduced to form metal nanowires along the direction of the electricfield between the AFM tip and the substrate. In this lithography process, TDA·HCl SAMs play an important role in the lithography process for improving the resolution of cobalt nanopatterns by preventing nonspecific reduction of cobalt ions on the unwritten background. Cobalt nanowires and nanodots with width of 225±26 nm and diameter of 208±28 nm were successfully fabricated. Platinium-coated polydimethylsiloxane (PDMS) stamp was used fabricating bulk cobalt structures which can be detected by energy dispersive X-ray spectroscopy for element analysis and the physical and magnetic properties of these cobalt nanopatterns were characterized using AFM and magnetic force microscope.