AVS 51st International Symposium
    Magnetic Interfaces and Nanostructures Friday Sessions
       Session MI-FrM

Paper MI-FrM7
Hierarchical Self-Assembly as a Route to Future Magnetic Data Storage

Friday, November 19, 2004, 10:20 am, Room 304A

Session: Advanced Magnetic Data Storage and Thin Film Processing
Presenter: S.B. Darling, Argonne National Laboratory
Authors: S.B. Darling, Argonne National Laboratory
D. Sundrani, The University of Chicago
S.J. Sibener, The University of Chicago
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A novel hybrid top-down/bottom-up approach is used to hierarchically organize magnetic nanoparticles on the nanoscale. Lithographically prepared substrate channels direct the self-assembly of a high-aspect ratio diblock copolymer template resulting in nearly defect-free alignment over arbitrarily long distances.@footnote 1@,@footnote 2@ Selective wetting of the channel sidewalls by one block initiates the organization and is followed by coarsening until the entire channel volume contains aligned domains. Overfilling the channels further extends the alignment, originally nucleated on the sidewalls, both above and beyond the confined space. This approach may be useful for globally aligning domains across an entire surface with the top interface being nearly flat despite the corrugated substrate underneath. The oriented structures are surprisingly defect-tolerant, accommodating roughly 10% variations in channel width without introducing disclination or dislocation defects. The laterally alternating nanoscale structure of the diblock film is then used to template the adsorption of FePt nanoparticles. Attractive interaction of the nanocrystal capping molecules with one of the polymer blocks leads to nearly 100% selective adsorption. Hybrid hierarchical approaches such as this are promising candidates for high density storage media. @FootnoteText@ @footnote 1@ D. Sundrani, S.B. Darling, S.J. Sibener, Nano Letters, 4 (2004) 273-276.@footnote 2@ D. Sundrani, S.B. Darling, S.J. Sibener, Langmuir, In Press.