Composite Gold/Magnetite Plasmonic-Magnetic Media Based on Self-Organization

We report the fabrication and the optical characterization of a composite system featuring optically-coupled plasmonic and magnetic components consisting of a 2-dimensional layer of magnetite (Fe3O4) nanocrystals (NC) laid onto a self-organized planar array of Au nanoparticles (NP). The regular arrays of Au NPs were fabricated by deposition onto a LiF(110) insulating surface nanopatterned by self-organization methods. The magnetite NCs were deposited from colloidal suspension onto the Au array by dip-and-dry procedures. The Au NPs exhibit a sharp localized surface-plasmon resonance (SPA) in their optical response at wavelength of approximate to 1550-600 nm. The SPR redshifts by approximate to 25 nm upon the deposition of the magnetite NC, due to the optical coupling between the plasmonic and the magnetic media. Optical modelling and atomic-force microscopy characterization suggest that a single, highly homogeneous monolayer of magnetite NC was formed on top of the Au NP array. The magnetite NC preserve their magnetic response following the deposition.