Dynamic hysteresis scaling behavior in polyvinylidene fluoride-trifluoroethylene ferroelectric copolymer thin films

In this paper, we investigated the dependence of dynamic hysteresis on the electric field amplitude E-0 and the frequency f in organic ferroelectric copolymer polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] thin films prepared by a spin-coating method on fluorinedoped tin oxide conductive glass. Three stages can be observed of the hysteresis area vs the field strength E-0. In stage I of low E-0 values, the area < A > dependent on E-0 follows the law of < A > proportional to E-0(1.92795), whereas the diverse distribution of the area < A > with frequency f is found. In stage II of the intermediate E-0 values, < A > proportional to E-0(beta) is not applicable owing to collective contributions between 180 degrees domain and chiral domain, while a relation of < A > proportional to f(-0:18636) can be deduced, a fascinating characteristic distinguishing from the nonlinear relations of the inorganics in this section. In stage III of high E-0 values, the scaling law is < A > proportional to f(0.08447)E(0)(0.49394) where the chiral domain is active. The positive beta in the law of < A > proportional to f alpha E-0(beta) illustrates that a growing number of chiral domains in P(VDF-TrFE) can keep pace with the variation of E-0. Especially, the negative alpha in the transition zone, resembling some inorganics under low electric fields, probably indicates 180 degrees domain reversal failing to follow with the alternating velocity of the increasing periodic electric field.

Automated summary

This paper investigates the effect of electric field amplitude (E-0) and frequency (f) on the dynamic hysteresis in organic ferroelectric copolymer thin films. Three stages of hysteresis area vs field strength are observed. In the first stage, the area (<A>) follows a proportional relationship with E-0, while the distribution of <A> varies with frequency f. In the second stage, the relationship between <A> and E-0(beta) is not applicable, but a relationship of <A> proportional to f(-0.18636) is found. In the third stage, a scaling law is observed with <A> proportional to f(0.08447)E(0)(0.49394) indicating the presence of chiral domains.