Hamburg 2001 – wissenschaftliches Programm
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DF: Dielektrische Festkörper
DF 6: Poster
DF 6.14: Poster
Mittwoch, 28. März 2001, 14:30–18:00, Foyer S3
Size effect in Mn-doped BaTiO3 nanopowders observed by XRD and EPR — •Rolf Boettcher1, Carola Klimm1, Christoph Semmelhack1, Georg Voelkel1, Hans-Juergen Glaesel2, and Eberhard Hartmann2 — 1Fakultaet fuer Physik und Geowissenschaften, Universitaet Leipzig — 2Institut fuer Oberflaechenmodifizierung (IOM e.V.) Leipzig
Ultrafine BaTiO3 powder samples doped with Mn2+ ions were studied by X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) techniques, taking EPR spectra in the (9.5 GHz), Q (34.2 GHz), and W (94.1 GHz) frequency bands. The determined quantities such as average crystallite size, size distribution, unit cell deformation c/a-1, axial fine structure parameter D, the distribution width of the latter and the EPR intensity ratio of the cubic and tetragonal Mn2+ sites are used to develop a more comprehensive insight into small particles. Large enough crystallites consist of a regular ferroelectric core surrounded by a peripheral particle layer with distorted translational symmetry. In crystallites smaller than 40 nm the regular no longer exists.