Linear electro-optic and piezoelectric coefficients of the relaxor ferroelectric P(VDF-TrFE) copolymer

The piezoelectric and the linear electro-optic (E-O) properties of the relaxor ferroelectric poly(vinylidene fluoride-trifluoroethylene) copolymer were investigated under various DC bias conditions, The linear E-O coefficients show a field dependence and are ∼35 pm/V at 60 V/μm DC bias field. When combining the piezoelectric coefficient, ∼ -180 pC/N, the copolymer exhibits a real linear E-O coefficient of ∼ -20 pm/V at a 60 V/μm DC bias field, Calculations based on the density functional theory suggest that the E-O effect is caused mainly by a phase transition between the non-polar and the polar phases.