MSE Colloquium
Date: April 30, 2010 from 2:00 pm to 3:00 pm EDT
Location: 214 S. W. Mudd
Contact: For further information regarding this event, please contact APAM Department by sending email to seasinfo.apam@columbia.edu or by calling 212-854-4457.
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Finite curvature: ferroelectricity and electronic transport in single- and multi-component nanostructuredmaterials


Jonathan Spanier, Drexel University

The study of ferroelectric (FE) nanostructures is motivated in part by opportunities for innovation involving effects of finite size, of shape, and of surface chemical environment on the structural and functional phase stability. Recent advances in the syntheses of FE nanostructures, e.g. nanoparticles, nanowires and nanotubes, have renewed interest in the miniaturization of ferroic materials for use as memory elements and for energy applications.  In this talk I shall discuss our recent work in the scanned proximal probe-based analyses and model calculation results involving FE polarizations within individual ABO3 oxide perovskite nanoshells and nanocrystals, and the responses of prototype nanoscale memory and transistor devices.  A wide range of interesting effects can be observed in the nanoshells and related nanostructures, including finite-size evolution of the FE phase transition temperature and unexpected FE stability, of enhancements in FE properties with finite size and with finite curvature, hysteretic current-voltage characteristics, and ferroelectric gating. These effects can be understood in terms of a mesoscopic symmetry-lowering and resulting strain profile(s), of molecular adsorbates, and of a redox process.  Work supported by the ARO and the NSF.

Host: Irving Herman