ULTRATHIN FERROELECTRIC POLYMER-FILMS

We have established ferroelectric switching and observed a novel condu ctance switching phenomenon in the first ultrathin ferroelectric polym er films fabricated by the Langmuir-Blodgett technique. The films cons ist of up to thirty monolayers of a copolymer of vinylidene fluoride ( 70%) and trifluoroethylene (30%) and exhibit classic ferroelectric beh avior, including a first-order ferroelectric phase transition, polariz ation reversal (switching), thermal hysteresis of the capacitance, fie ld-dependent switching dynamics, pyroelectricity, and piezoelectricity . The results of polarization, capacitance, switching, spectroscopic, and pyroelectric measurements on these highly crystalline and fully or iented films provide unprecedented detail concerning the thermodynamic properties of the ferroelectric and nonferroelectric states in ultrat hin polymer films. The electric field and the film thickness have a st rong influence on the ferroelectric properties.