The polar nanostructure of novel relaxor ferroelectric materials. (News Briefs).
Scientists at the NIST Center for Neutron Research (NCNR) and Brookhaven National Lab have an ongoing collaborative program to study the lattice dynamics (atomic vibrations) in the PZN and PMN relaxor compounds. Recent neutron inelastic scattering measurements at the NCNR have demonstrated a direct relationship between the lowest-frequency transverse optical lattice vibration and the polar nanostructure, thereby resolving a long-standing discrepancy between prior x-ray and neutron results. In PMN this vibrational mode becomes overdamped at 620 K, which is the same temperature at which the polarized nanometer-scale domains begin to develop. Concurrently, an unusual broadening of the transverse acoustic vibrational mode begins at 620 K, and increases strongly with decreasing temperature. These results indicate that this optical lattice vibration condenses into the polar nanoregions, resulting in a non-uniform distortion of the crystal lattice.
Subsequent experiments to clarify further how the polar nanoregions are responsible for the novel piezoelectricity observed in these and other relaxor systems are underway.
CONTACT: Peter Gehring, (301) 975-3946; peter. email@example.com.
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|Publication:||Journal of Research of the National Institute of Standards and Technology|
|Article Type:||Brief Article|
|Date:||Mar 1, 2002|
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