Preisach modeling of ferroelectric pinched loops

The Preisach approach is applied to model ferroelectric pinched (or constricted) loops. Starting from the existence of distributed switchable dipolar defects in the material and a corresponding distribution function, an analytical expression for the resulting ferroelectric loop is obtained. The corresponding hysteresis shape is indeed showing a clear pinching. Considerations about defect distribution expression and ways to characterize it from the loop are also made. It is finally suggested that such a description can be applied to any system exhibiting a pinched loop. (C) 2000 American Institute of Physics. [S0003-6951(00)02651-6].