Effect of bias electric field on phase transition in vinylidene fluoride-trifluoroethylene copolymers

The pyroelectric constant of poled VDF/TrFE copolymers shows a peak during heating associated with a ferroelectric phase transition. When the bias electric field is applied in the same direction as the remanent polarization, the peak shifts to higher temperature. When the bias electric field is applied in the reverse direction, the peak shifts to lower temperature followed by reversal of the sign of the pyroelectric constant and a second peak. The shift of peak temperature with bias field is discussed on the basis of Clausius Clapeyron´s equation.