Correlation between number of ferroelectric variants and coercive field of lead ziconate titanate single crystals

Understanding the magnitude of coercive fields, the external electric field that results in zero net polarization, has been a long-standing problem for ferroelectrics. The authors studied the switching and coercive fields using a combination of the continuum phase field approach, microelasticity, and electrostatics. While the values of coercive fields predicted from the phenomenological thermodynamic theory assuming a single ferroelectric domain or the theory of nucleation are at least one order of magnitude too high compared to those measured experimentally, the predictions incorporating structural inhomogeneities show remarkably good agreement with experimental measurements, revealing the critical role of multidomain/variants in polarization switching. (C) 2007 American Institute of Physics.