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胡志军教授课题组在Physical Review Letters(IF7.512)上发表研究论文

发布时间:2017-05-03 10:44

Title:Two-Step Polarization Switching in Ferroelectric Polymers 

Author:Yangjiang Wu, Xiaohui Li, Alain M. Jonas, and Zhijun Hu* 

Abstract: The correlation between hierarchical structures and polarization switching in ferroelectric poly(vinylidene fluoride-ran-trifluoroethylene) has been probed by combining transmission electron microscopy studies with piezoresponse force microscopy observations. Differences are demonstrated between homogeneous and anisotropic thin films with well-defined lamellar orientation, with the later exhibiting quadrangular domain shape and double hysteresis. We propose that the polarization switching within lamella is dominated by domain wall flow motion, while the amorphous components between lamellae impede full polarization switching. The coupling between lamellae is controlled by a creep process. These results and interpretations explain well the seemingly contradicting polarization reversal dynamics reported and offer opportunities to change domain reversal speed by making ferroelectric polymer nanostructures.