  Statistical distribution of switching times is a key information necessary to
describe the dynamic response of a polycrystalline bulk ferroelectric to an
applied electric field. The Inhomogeneous Field Mechanism (IFM) model offers a
useful tool which allows extraction of this information from polarization
switching measurements over a large time window. In this paper, the model was
further developed to account for the presence of non-switchable regions in
fatigued materials. Application of the IFM- analysis to bipolar electric
cycling induced fatigue process of various lead-based and lead-free
ferroelectric ceramics reveals different scenarios of property degradation.
Insight is gained into different underlying fatigue mechanisms inherent to the
investigated systems.
