Fabrication of cobalt magnetic nanostructures using atomic force microscope lithography

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Cobalt nanopatterns are essential for advanced magnetic storage devices.
• Developing high-resolution fabrication methods for these nanostructures is crucial.
• Self-assembled monolayers (SAMs) offer potential for controlled surface modification.

Purpose of the Study:

• To demonstrate a novel method for fabricating cobalt magnetic nanostructures.
• To investigate the role of n-tridecylamine x hydrochloride (TDA x HCl) SAMs in improving nanopattern resolution.
• To characterize the physical and magnetic properties of the fabricated cobalt nanostructures.

Main Methods:

• Direct writing atomic force microscope (AFM) lithography was employed.
• Localized electrochemical reduction of cobalt ions on TDA x HCl SAM-modified silicon surfaces.
• Fabrication of cobalt nanowires and nanodots using AFM tip-substrate electric field.
• Characterization using AFM, magnetic force microscopy (MFM), and energy dispersive X-ray spectroscopy (EDS).

Main Results:

• Successfully fabricated cobalt nanowires (width 225 ± 26 nm) and nanodots (diameter 208 ± 28 nm).
• TDA x HCl SAMs effectively prevented non-specific cobalt ion reduction, enhancing pattern resolution.
• Demonstrated the formation of metal nanowires along the electric field direction.
• Characterized physical and magnetic properties of the cobalt nanopatterns.

Conclusions:

• The demonstrated AFM lithography technique enables high-resolution fabrication of cobalt nanopatterns.
• TDA x HCl SAMs are critical for achieving precise cobalt nanostructure formation.
• This method holds promise for applications in patterned magnetic storage.