Dielectric properties of self-assembled spherulite films of organic ferroelectric 2-methylbenzimidazole

Thin films of organic ferroelectric 2-methylbenzimidazole (MBI) were grown by evaporation method on different substrates. The films consist of self-assembled spherulite blocks formed by elongated crystallites of MBI. Temperature, frequency, and electric field amplitude variations of in-plane hysteresis dielectric loops were measured using interdigital system of electrodes and compared with analogous dependences in MBI single crystals. Simulation of remnant polarization P-rem dependence on amplitude of electric field E-max in films is carried out in frames of a model considering the dipole moment of block as a sum of dipole moments of crystallites, which form spherulite with account of different orientation of crystallites relative to applied electric field. Deviations from the model are assosiated with complicated domain structure and presence of depolarizing fields.