Monodisperse Oxide Nanoparticles with Applications in Ferroelectrics
Stephen OBrien*, a, Louis E. Brusa, Chris B. Murrayb
aColumbia University,
New York, NY 10027 USA
bIBM Corp. T. J. Watson Research Center
This is an abstract
for a presentation given at the
Eighth
Foresight Conference on Molecular Nanotechnology.
There will be a link from here to the full article when it is
available on the web.
The synthesis and structural characterization of relatively monodisperse nanoparticles of barium titanate (BaTiO3) is presented. The nanoparticles exist as an organic ligand-stabilized suspension in organic solvents for purposes of processing. The electric properties of thin films of barium titanate nanoparticles have been investigated. The ferroelectric and dielectric properties of metal oxides with the perovskite structure are highly dependent on particle shape and size, especially in the nanoscale region. The spontaneous and reversible electric dipole moment, characteristic of ferroelectric metal oxides in an applied electric field, originate from ion displacement in the crystal unit cell. The behavior of this dipole moment in the bulk material is a function of ferroelectric domain size and domain-domain interactions. An understanding of this phenomenon would be considerably enhanced by the ability to study the ferroelectric properties of a material progressing from nanoscale (a limited number of unit cells) to bulk. It is therefore of importance to develop a rational synthesis of monodisperse oxide nanoparticles which would allow control of particle size and shape, and permit facile manipulation using chemical techniques.
Oxide ferroelectric nanoparticles may exhibit very interesting cooperative self-assembly, especially in the presence of applied electric fields. Further, if the individual nanoparticles can be 'poled' then nanoparticles tagged to biological molecules would exhibit novel spontaneous alignment/re-orientation in the presence an electric field. Scanning probe microscopy of ferroelectric nanoparticles (using AFM/EFM) allows the potential for singe particle electric field measurements, currently under investigation.
*Corresponding Address:
Stephen OBrien
Columbia University
Havemeyer Hall, 3000 Broadway,
New York, NY 10027 USA
Email: [email protected]
Web: http://www.columbia.edu/~so188
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