We report a novel nanomanufacturing technique that incorporates patterned arrays built entirely from Fe₃O₄ nanoparticles into a flexible and transparent polymer film. First, the nanoparticles are patterned using the enormous magnetic field gradients at the surface of commercial disk drive media, and then the resulting architecture is transferred to the surface of a polymer film by spin-coating and peeling. Since the particles are immobilized by the field gradients during the spin-coating process, the patterned array is preserved after peeling. To demonstrate the potential of this technology, we fabricate a 5 mm diameter all-nanoparticle diffraction grating capable of producing a white-light optical spectrum. We also demonstrate several extensions to this technology, where, by adding an external magnetic field during assembly, we create both periodic variations in topography, as well as a nanocomposite with two vertically and horizontally separated nanoparticle layers. As this technique leverages the nanometer resolution inherent in current magnetic recording technology, strong potential exists for low-cost nanomanufacturing of optical and electronic devices from a variety of nanomaterials with ∼10 nm resolution.

In the present study, the single layer Co 90 Fe 10 and X/Co 90 Fe 10 (X = Cu, Cr, Au, Ni 80 Fe 20) double layer films were investigated. Films were fabricated by DC magnetron sputtering at room temperature on Si substrates. In order to improve the soft magnetic properties of CoFe films, four different underlayers were examined. The coercivity values of the films were obtained by using a laboratory design magneto-optic Kerr effect (MOKE) magnetometry. Magnetic force microscopy and x-ray diffraction results show that the crystalline structure and magnetic domains of CoFe films are sensitive to the initial layer. It was seen that the soft magnetic properties of CoFe films were improved with underlayers. Particularly, the Au underlayer was effective in reducing coercivity H c from 37 to 5 Oe.

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