Berlin 2008 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 7: Point defect spectroscopy and engeneering
DF 7.3: Vortrag
Dienstag, 26. Februar 2008, 11:20–11:40, EB 107
Local structure and symmetry of paramagnetic ions in microscopic and nanoscopic ferroelectric materials — •Emre Erdem1, Kamil Kiraz2, Mehmet Somer2, and Rüdiger -A. Eichel1 — 1Eduard-Zintl-Institut, Technische Universität Darmstadt, D-64287 Darmstadt, Deutschland — 2Koc University, Department of Chemistry, Rumelifeneri Yolu, Sariyer, 80910 Istanbul Turkey
In this work, multi-frequency (9.5 GHz up to 319 GHz) electron paramagnetic resonance (EPR) spectroscopy is used in order to study the role of aliovalent and isovalent functional centres and their impact on lattice vacancies in PbTiO 3 and PbZrxTi1−xO 3 . The examination of nanocrystalline ferroelectrics with perovskite structure and the determination of their physical and chemical properties are one of the challenges of the solid state physics and material science due to their potential application in device technology. To determine the structural changes which occur in correlation with size effects and size driven phase transition in PbTiO 3 , dielectric, Raman and multi-frequency EPR measurements were carried out on Cr, Fe, Gd and Cu doped micro- and nanopowders. Through the size-dependent multi-frequency EPR spectra the spin-Hamiltonian parameters were determined and correlated with structural investigations and dielectric measurements.