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SUMMARY:Domain switching in ferroelectric perovskites and applications - P
 rofessor Kaushik Bhattcharya\, CalTech
DTSTART:20090123T143000Z
DTEND:20090123T150000Z
UID:TALK16103@talks.cam.ac.uk
CONTACT:Ms Helen Gardner
DESCRIPTION:This talk will describe recent theoretical and experimental in
 vestigations of domain switching in ferroelectric perovskites.  The motiva
 tion for this work is actuator\, sensor and optical applications.  We begi
 n with a theoretical model of single crystal materials\, and use it to mot
 ivate an approach to large strain electrostriction under combined electro-
 mechanical loads.  We describe the experimental set up and results that de
 monstrate this large strain electrostriction.  We generalize the model to 
 recognize the fact that ferroelectric materials are wide-band-gap semicond
 uctors\, and discuss its consequences on depletion layers\, domain walls a
 nd defect diffusion.  We then turn to ceramics or polycrystals.  We presen
 t a theoretical analysis that shows that intergranular constraints against
  90 degree domain switching depend on the symmetry of the material.  This 
 provides a new insight into the important of compositions in lead titanate
  zirconate.  We close with some new ideas towards constructing tunable pho
 tonic devices using ferroelectric perovskites.
LOCATION:LR6\, Department of Engineering
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