The Debye-like relaxation mechanism in poly(vinylidene fluoride- trifluoroethylene) ferroelectric polymers

In this work we studied 65-nm-thick poly(vinylidene fluoride- trifluoroethylene) ferroelectric polymers films grown by Langmuir-Blodgett onto silicon substrates. Three dielectric anomalies have been unambiguously evidenced. The high temperature one near 380 K corresponds to the ferroelectric-paraelectric transition. The low temperature one near 270 K which is characterized by a relaxation is attributed to structural defects in the crystalline phase leading to inhomogeneous strains detected by x-ray diffraction. At approximately 320 K, a Debye-like relaxation is clearly evidenced. Possible origins for this later relaxation are discussed.