Shift and deformation of the hysteresis curve of ferroelectrics by defects: An electrostatic model

Lattice cells containing point defects in ferroelectric single crystals can behave as a second phase. In addition to the role these defects have in the variation of several chemical and physical properties of the ferroelectric, they modify those physical properties of the ferroelectric that are manifested in the hysteresis curve. These effects are: the shearing of the loop by all kinds of defects, the shifting of the hysteresis curve along the field axis (internal bias) by oriented polar defects, and the changing (mostly the increasing) of the coercive field strength. An electrostatic model is used to calculate the strength of these effects.