Theory of electric creep and electromechanical coupling with domain evolution for non-poled and fully poled ferroelectric ceramics

• Published in: Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences Vol. 472; no. 2194; p. 20160468
• Main Authors: Xia, Xiaodong, Wang, Yang, Zhong, Zheng, Weng, George J.
• Format: Journal Article
• Language: English
• Published: England The Royal Society Publishing 01.10.2016
• Subjects: Dissipation Potential; Domain Evolution; Electric Creep; Electromechanical Coupling; Ferroelectric Ceramics; Thermodynamic Driving Force; ferroelectric ceramics; dissipation potential; electric creep; electromechanical coupling; domain evolution; thermodynamic driving force
• ISSN: 1364-5021; 1471-2946
• DOI: 10.1098/rspa.2016.0468

Unlike mechanical creep with inelastic deformation, electric creep with domain evolution is a rarely studied subject. In this paper, we present a theory of electric creep and related electromechanical coupling for both non-poled and fully poled ferroelectric ceramics. We consider electric creep to be a time-dependent process, with an initial condition lying on the D (electric displacement) versus E (electric field) hysteresis loop. Both processes are shown to share the same Gibbs free energy and thermodynamic driving force, but relative to creep, the hysteresis loop is just a field-dependent process. With this view, we develop a theory with a single thermodynamic driving force but with two separate kinetic equations, one for the field-dependent loops in terms of a Lorentzian-like function and the other for the time-dependent D in terms of a dissipation potential. We use the 0°–90° and then 90°–180° switches to attain these goals. It is demonstrated that the calculated results are in broad agreement with two sets of experiments, one for a non-poled PIC-151 and the other for a fully poled PZT-5A. The theory also shows that creep polarization tends to reach a saturation state with time and that the saturated polarization has its maximum at the coercive field.