  The kinetic theory of switching processes in crystalline ferroelectric
materials under the influence of a variable external electric field is
formulated. The basic equations are derived and their exact analytical solution
at arbitrary time-dependent external field are obtained. Connection between the
hysteresis loops shape and variable external electric field parameters is
investigated numerically. The numerical results were found to be in excellent
agreement with the experiments. PACS: 77.80.Fm, 77.80.Dj, 77.80.-e Keywords:
ferroelectrics, switching processes, hysteresis curves, polarization
