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 fluorine-doped 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 ⟩ ∝ 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 ⟩ ∝ E 0 β is not applicable owing to collective contributions between 180° domain and chiral domain, while a relation of ⟨ A ⟩ ∝ 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 ⟩ ∝ f 0.08447 E 0 0.49394 where the chiral domain is active. The positive β in the law of ⟨ A ⟩ ∝ f α E 0 β illustrates that a growing number of chiral domains in P(VDF-TrFE) can keep pace with the variation of E 0 . Especially, the negative α in the transition zone, resembling some inorganics under low electric fields, probably indicates 180° domain reversal failing to follow with the alternating velocity of the increasing periodic electric field.