Arrays of nanoscale magnetic dots: Fabrication by x-ray interference lithography and characterization

Heyderman, L.J.; Solak, H.H.; David, C.; Atkinson, D.; Cowburn, R.P.; Nolting, F.

Abstract

X-ray interference lithography (XIL) was employed in combination with electrodeposition to fabricate arrays of nanoscale nickel dots which are uniform over 40 µm and have periods down to 71 nm. Using extreme-ultraviolet light, XIL has the potential to produce magnetic dot arrays over large areas with periods well below 50 nm, and down to a theoretical limit of 6.5 nm for a 13 nm x-ray wavelength. In the nickel dot arrays, we observed the effect of interdot magnetic stray field interactions. Measuring the hysteresis loops using the magneto-optical Kerr effect, a double switching via the vortex state was observed in the nickel dots with diameters down to 44 nm and large dot separations. As the dot separations are reduced to below around 50 nm a single switching, occurring by collective rotation of the magnetic spins, is favored due to interdot magnetic stray field interactions. This results in magnetic flux closure through several dots which could be visualized with micromagnetic simulations. Further evidence of the stray field interactions was seen in photoemission electron microscopy images, where bands of contrast corresponding to chains of coupled dots were observed.

Citation

Heyderman, L., Solak, H., David, C., Atkinson, D., Cowburn, R., & Nolting, F. (2004). Arrays of nanoscale magnetic dots: Fabrication by x-ray interference lithography and characterization. Applied Physics Letters, 85(21), 4989-4991. https://doi.org/10.1063/1.1821649

• Journal Article Type: Article
• Publication Date: Nov 22, 2004
• Deposit Date: Mar 27, 2008
• Publicly Available Date: Apr 21, 2011
• Journal: Applied Physics Letters
• Print ISSN: 0003-6951
• Electronic ISSN: 1077-3118
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 85
• Issue: 21
• Pages: 4989-4991
• DOI: https://doi.org/10.1063/1.1821649
• Keywords: Nickel, Nanostructured materials, Ferromagnetic materials, Electrodeposition, X-ray lithography, Micromagnetics, Arrays, Magnetic hysteresis, Kerr magneto-optical effect, Spin dynamics, Magnetic switching, Exchange interactions (electron), Photoelectron m
• Public URL: https://durham-repository.worktribe.com/output/1619301