Dresden 2014 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 55: Poster II
MA 55.104: Poster
Freitag, 4. April 2014, 10:30–13:30, P2
Investigation of Binding Energies in Multiferroic Layer Systems — •Martin Welke1, Paula Huth1, Kathrin Dabelow2, Karl-Michael Schindler2, Angelika Chassé2, and Reinhard Denecke1 — 1Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig — 2Institut für Physik, Martin-Luther-Universität Halle-Wittenberg
The work presented deals with the electronic structure of ferroelectric BaTiO3 (BTO) and additional ferrimagnetic layers on top. BTO has several phase transitions while the biggest change occurs during the phase transition from tetragonal to cubic where the electrical polarization disappears. In conventional XPS measurements, there are spontaneous shifts in core-level binding energies while heating or cooling through that last mentioned phase transition. That observation was proposed to be a surface effect.[1] In order to check this property, different photon energies ranging from 2000 to 6000 eV have been used to excite photoelectrons with higher kinetic energy to probe the sample in greater depths. Core levels of all contained elements were studied showing shifts in binding energy as well. Therefore, we assume it is not a plain surface effect but might occur throughout the whole bulk of the ferroelectric material. Additionally, layers of CoFe2O4 and NiFe2O4 on BTO prepared by PLD have been investigated showing these shifts in binding energies as well. Theoretical simulations were performed in order to obtain a detailed understanding of the influence of the crystal lattice of BaTiO3 and of the shifts observed in binding energies.
[1] L. Makhova et al., Phys. Rev. B, 2011, 83, 115407