Ferroelectric betaine phosphite films: Growth, optical imaging, and dielectric properties

Abstract

Polycrystalline films of betaine phosphite (BPI) were grown by evaporation method on SiO2 and LiNbO3 substrates with interdigital transducers. Large (∼1 mm) single-crystalline blocks were visualized in a polarizing microscope in the reflection mode. Temperature dependences of the film capacity at frequencies 120 Hz-1 MHz exhibit a strong maximum at the temperature of the ferroelectric phase transition of BPI bulk crystals. The effect of a bias electric field was studied. Temperature variations in dielectric permittivity and electric field effect are analyzed using a thermodynamic model accounting for the substrate-film interaction. © 2008 American Institute of Physics.