Structural characterization of CuO-doped alkali niobate piezoelectric ceramics by electron paramagnetic resonance spectroscopy [Elektronische Ressource] / vorgelegt von Ebru, Erünal

Structural Characterization ofCuO-doped Alkali NiobatePiezoelectric Ceramics byElectron Paramagnetic ResonanceSpectroscopyINAUGURALDISSERTATIONzur Erlangung des Doktorgradesder Fakultät für Chemie, Pharmazie und Geowissenschaftender Albert-Ludwigs-Universität Freiburg im Breisgauvorgelegt vonEbru, Erünalaus Ankara, Türkei2011Vorsitzender des Promotionsausschusses : Prof. Dr. Rolf SchubertReferent : PD. Dr. Rüdiger-A. EichelKorreferent : Prof. Dr. Stefan WeberDatum der Promotion : 02.02.2011AbstractAlkali niobate ceramics are promising ‘lead-free’ alternatives for currently usedPb(Zr,Ti)O piezoelectric materials. In this thesis, the defect structure of CuO-doped3alkali niobate ceramics were investigated depending on the alkali and niobiumnon-stoichiometry, process conditions (calcination and sintering) and CuO-dopingamount by means of multi-frequency Electron Paramagnetic Resonance (EPR)Spectroscopy. Moreover, the atomic scale information provided through EPR analysiswas supported by theoretical DFT calculations and compared to a microstructural(with XRD and SEM characterization) analysis. The samples under study wereprepared through a mixed-oxide-carbonate route. The CuO-doping content was keptcomparatively low at 0.25 mol% to minimize the secondary-phase formation effects.