General features of the intrinsic ferroelectric coercive field

The value of the intrinsic ferroelectric coercive field is obtained indepen dently, from general energy considerations and from the predictions of seve ral models of the ferroelectric state. All predictions yield a value of the order of the depolarization field, which is equal to the spontaneous polar ization divided by the dielectric permittivity, and are consistent with the recent measurements of the intrinsic ferroelectric coercive field in ultra thin Langmuir-Blodgett films of copolymers of polyvinylidene fluoride with trifluoroethylene. Prior studies succeeded only in measuring the much small er extrinsic coercive fields, which are limited by nucleation processes and domain motion. (C) 2001 MAIK "Nauka/Interperiodica".