Regensburg 2010 – wissenschaftliches Programm
DS 8.9: Vortrag
Montag, 22. März 2010, 16:15–16:30, H3
Multiferroicity in EuTiO3 and Eu1−xBaxTiO3: ab initio characterization of crystalline, magnetic and electronic structure — •Konstantin Z. Rushchanskii1, Marjana Ležaić1, and Nicola A. Spaldin2 — 1Institut für Festkörperforschung, Quanten-Theorie der Materialien, Forschungszentrum Jülich GmbH, 52425 Jülich, and JARA-FIT, Germany — 2Materials Department, University of California, Santa Barbara, CA 93106-5050, USA
We report a systematic study of possible structural transitions in EuTiO3 and ordered Eu1−xBaxTiO3 mixed compounds. We investigated phonon spectra of EuTiO3 and found strong M- and R-point instabilities, indicating antiferrodistortive structural deformations. In the ordered Eu0.5Ba0.5TiO3 compounds, the antiferrodistortive deformation is replaced by significant ferroelectric distortions, involving not only Ti, but also the magnetic Eu cation. We will discuss several scenarios of ferroelectric and antiferrodistortive transitions and their coupling with the magnetic structure. Corresponding changes in the phonon structure will be compared with available experimental data.
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