title: Investigation of the ferroelectric and DC-conductive properties and their coupling in organic ferroelectrics
creator: Mager, Heiko
subject: ddc-530
subject: 530 Physics
description: In this work the ferroelectric and DC-conductive properties of a series of fluorinated cyclohexane compounds and organic charge transfer complexes were investigated. For the former, ferroelectric polarization switching in thin films was proven by electrical double wave and capacitance-voltage measurements in conducting and non-conducting molecular derivatives. The ferroic parameters were well described by analytical polarization switching models. A mismatch of measured and theoretical polarization values in some of the materials could be explained by the modulation of their conductivity by the ferroelectric polarization. The finding of a significant conductivity was unexpected as the materials do not contain an extended π-electron system that is commonly seen as a requirement for electronic charge transport in organics. The conductivity was characterized electrically and the influence of structural supramolecular alignment observed in atomic-force microscopy and X-ray scattering was quantified. A general set of requirements for materials to exhibit this kind of conductivity was formulated and confirmed by extension of the experimental investigation to further compounds. Furthermore, ferroelectricity was proven for two of the charge-transfer complexes and their temperature dependent conductivity suggested a neutral-ionic transition with temperature. In stark contrast to previous results, the materials displayed ferroelectric behavior on both sides of the transition that is sitting just below room temperature.
date: 2025
type: Dissertation
type: info:eu-repo/semantics/doctoralThesis
type: NonPeerReviewed
format: application/pdf
identifier: https://archiv.ub.uni-heidelberg.de/volltextserver/37108/1/Dissertation%20Heiko%20Mager.pdf
identifier: DOI:10.11588/heidok.00037108
identifier: urn:nbn:de:bsz:16-heidok-371086
identifier:   Mager, Heiko  (2025) Investigation of the ferroelectric and DC-conductive properties and their coupling in organic ferroelectrics.  [Dissertation]     
relation: https://archiv.ub.uni-heidelberg.de/volltextserver/37108/
rights: info:eu-repo/semantics/openAccess
rights: http://archiv.ub.uni-heidelberg.de/volltextserver/help/license_urhg.html
language: eng