Self-assembly of magnetic nanoparticles in a liquid-crystalline media

ORAL

Abstract

We investigate the self-assembly of magnetic Fe$_{3}$O$_{4}$ nanoparticles (NPs) dispersed in a liquid crystal (LC) matrix. The NP assembly is driven by the temperature-induced transition of the LC from the isotropic to the nematic phase. Using magneto-optical Kerr effect (MOKE) and polarized optical miscroscopy, we observe that the NPs are mostly expelled into the isotropic regions, finally ending up clustered around LC defect points when the transition is complete. We use NPs with diameters between 10-30 nm and the concentration of NPs in the LC media range from 0.02{\%} to 0.2{\%} by weight. We find that the resulting NP assemblies exhibit superparamagnetic and ferrimagnetic behavior, depending on their sizes.

*This work was funded by NSF DMR - 1056860.

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Authors

  • Jose Amaral

    • University of California, Merced

  • R. Andosca

    • University of California, Merced

  • A.L. Rodarte

    • University of California, Merced

  • C.G.L. Ferri

    • University of California, Merced

  • Sayantani Ghosh

    • Physics Department, University of California, Merced
    • University of California, Merced
    • School of Natural Sciences, University of California, Merced, CA 95343 USA