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Publications (5)26.05 Total impact

  • Cherry A. Murray · David G. Grier
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    ABSTRACT: ▪ Abstract Colloidal suspensions of uniformly sized microspheres can serve as powerful model systems for investigating many-body processes in condensed-matter physics. The ensemble of microspheres in such suspensions undergoes disorder-order transitions from fluids to crystals in direct analogy with the structural transitions experienced by atoms in conventional materials. Unlike atoms, however, colloidal spheres can be imaged and tracked using optical microscopy and computerized image processing. This review addresses issues in the physics of phase transitions that have been attacked through digital video microscopy of colloidal dispersions over the past decade. Particular emphasis is placed on microscopic mechanisms of melting and freezing and on the effects of geometric confinement on these fundamental processes.
    No preview · Article · Nov 2003 · Annual Review of Physical Chemistry
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    ABSTRACT: A laser light source for high-resolution near-field optics applications with an output power exceeding 1 mW (104 times the power from previous sources) and small (300 nm square to less than 50 nm square) output beam size is demonstrated. The very-small-aperture laser (VSAL) tremendously expands the range of applications possible with near-field optics and increases the signal-to-noise ratios and data rates obtained in existing applications. As an example, 250-nm-diam marks corresponding to 7.5 Gb/in.2 storage density have been recorded and read back in reflection and transmission on a rewritable phase-change disk at 24 Mb/s with a 250-nm-square aperture VSAL. VSALs potentially enable data storage densities of over 500 Gb/in.2 (up to 100 times today’s magnetic or optical storage densities). © 1999 American Institute of Physics.
    Full-text · Article · Sep 1999 · Applied Physics Letters
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    ABSTRACT: Summary form only given. We discuss a near-field optical storage system based on a semiconductor laser that is placed within 25-200 nm of a storage medium using flying head techniques commonly used in magnetic storage. The relatively large powers (>10 /spl mu/W) radiating from the laser enable data rates of larger than 10 Mbit/s while the vicinity of the head to media presents the possibility of storage densities in excess of 50 Gbit/in/sup 2/. Such a performance presents this technique as a viable option for ultrahigh density storage.
    No preview · Conference Paper · Jul 1996
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    Jessica A. Weiss · David W. Oxtoby · David G. Grier · Cherry A. Murray
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    ABSTRACT: We describe a nonequilibrium phase transition in a geometrically confined charge‐stabilized colloidal suspension. The equilibrium configuration for the spheres in this system is a two‐layer square lattice, equivalent to two layers of a body‐centered cubic (bcc) crystal. After electrophoretic shear melting, the suspension rapidly crystallizes to a buckled single‐layer triangular lattice. This well‐ordered solid phase subsequently undergoes a martensitic phase transition back to the two‐layer square lattice. We use high resolution digital video microscopy to follow the emergence and evolution of order during these phase transitions. © 1995 American Institute of Physics.
    Full-text · Article · Jul 1995 · The Journal of Chemical Physics
  • David G. Grier · Cherry A. Murray
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    ABSTRACT: Using time‐resolved digital video microscopy, we have tracked the reemergence of order in charge‐stabilized colloidal crystals which have been shear melted into isotropic fluids. Crystallization is heterogeneously nucleated by the smooth walls of the sample container. This process is analogous to the solidification of conventional materials during casting or liquid phase epitaxy. The nonequilibrium freezing transition proceeds through the gradual formation of a layered fluid near the repulsive wall, subsequent evolution of local order within the first fluid layer, and ultimately rapid crystallization. After nucleation and initial growth, crystallites are observed to fracture, perhaps due to shear stresses imposed by neighboring crystallites. Microscopic measurements of the nonequilibrium self‐diffusion coefficient are consistent with the dynamical freezing criterion recently proposed for systems in equilibrium by Löwen et al. [Phys. Rev. Lett. 70, 1557 (1993)].
    No preview · Article · Jun 1994 · The Journal of Chemical Physics