In this article an experimental method of characterization and modeling of ferroelectric materials is presented. The reversible and irreversible contributions of polarization are separated. The measurements of these effects are performed simultaneously giving a perfect separation. Investigations on switching behavior under different electric field strengths permit final representation of totally irreversible effects by a two-dimensional (2D) function. This function, a Preisach-type density, allows us to extract traditional information such as remanent polarization, coercive field and so on. Then, this curve is fitted to a 2D Gaussian distribution in order to provide easy implementation in simulators. Finally, a physical model is considered to interpret this experimental function in terms of switching mechanism, leading to a powerful tool for future investigation, e.g., the origin of aging. (C) 2002 American Institute of Physics.