title: Asymmetric polarization and hysteresis behaviour in ferroelectric P(VDF-TrFE) (76 : 24) copolymer thin films spatially resolved via LIMM.
abstract: The concept of charge-polarization coupling in the ferroelectric copolymer PVDF-TrFE (poly[vinylidene fluoride-co-trifluoroethylene]) has been revisited by employing high resolution (<50 nm) pyroelectric depth profiling (LIMM). By virtue of probing the pyroelectric activity over the film thickness in the presence of a variable, external electrical field, the local ferroelectric response and spatially resolved hysteresis could be obtained. A large asymmetry was found between the positive and negative electrode-polymer interface. Differences in amplitude of polarization, contribution of interface charges and length scale of the polarization-free zone near the electrodes suggest a higher availability of compensation charges at the negative electrode that finally stabilize the local polarization. The resulting asymmetries in the polarization distribution are hence attributed to excess charges as a result of electron injection as a specific charge generation mechanism at the negative electrode.
authors.affiliation: Dept. of Physics and Astronomy, Soft Matter and Biophysics section, KU Leuven, Leuven, Belgium. tristan.putzeys@fys.kuleuven.be michael.wubbenhorst@fys.kuleuven.be.
authors.forename: T
authors.initials: T
authors.lastname: Putzeys
authors.forename: M
authors.initials: M
authors.lastname: Wübbenhorst