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Title:Dielectric noise spectroscopy of relaxor ferroelectrics
Author(s):O'Brien, Kevin Patrick
Doctoral Committee Chair(s):Weissman, Michael B.
Department / Program:Physics
Subject(s):dielectric noise
relaxor ferroelectrics
mesoscopic capacitor
Abstract:This thesis attempts to answer one simple question: are the dynamics of relaxor ferroelectrics cooperative? To accomplish this task, we have developed a promising new technique that is excellent at sorting out the internal dynamics of high dielectric materials. Specifically we have examined the dynamics of the relaxor ferroelectric material PLZT(B/65/35) in the "frozen" state. A relaxor ferroelectric is a material which has local ferroelectric order on the 1 Onm scale (nanodomains) but on longer scales the material is disordered. The nanodomains appear to go through a freezing transition and it is not known whether this is a cooperative effect. DNS examines the details of the polarization fluctuations from a mesoscopic capacitor, our smallest capacitor has an effective volume of 2x1Q-12cm3, or 107 nanodomains. From the statistical details, the lack of any non-Gaussian noise in this case, we are able to set an upper limit on the number of nanodomains that can act cooperatively in both equilibrium and near equilibrium.
Issue Date:1997
Genre:Dissertation / Thesis
Other Identifier(s):4047197
Rights Information:©1997 O'Brien
Date Available in IDEALS:2012-05-04

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