Regensburg 2000 – wissenschaftliches Programm

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DF: Dielektrische Festkörper

DF 5: Keramiken

DF 5.7: Vortrag

Dienstag, 28. März 2000, 17:10–17:30, H11

Size effect in Mn²⁺ doped barium titanate nanopowders observed by means of EPR — •Rolf Boettcher¹, Carola Klimm¹, Christoph Semmelhack¹, Georg Voekel¹, Hans-Juergen Glaesel², and Eberhard Hartmann² — ¹Fakultaet fuer Physik und Geowissenschaften, Universitaet Leipzig, D-04103 Leipzig — ²Institut fuer Oberflaechenmodifizierung (IOM e. V.), D-04318 Leipzig

Barium titanate (BaTiO₃) ultrafine powders have been prepared from a monomeric metallo-organic precursor through combined solid-state polymerization and pyrolysis. The ultrafine Mn²⁺ doped BaTiO₃ powder samples with an average grain size varying from 15 nm to 155 nm were studied by x-ray diffraction (XRD) and electron paramagnetic resonance(EPR) techniques. The determined quantities such as grain size, unit cell deformation c/a⁻¹, the axial fine structure (FS) parameter D, the distribution width of the latter, and the EPR intensity ratio of cubic and tetragonal Mn²⁺ sites are used to develop a more comprehensive insight in small particles.