Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 21: Clean surfaces: Metals, semiconductors, oxides and insulators II

O 21.2: Vortrag

Montag, 14. März 2011, 17:30–17:45, WIL B122

Imaging domain structures of ferroelectric and multiferroic surfaces by PEEM — •Anke Höfer, Klaus Duncker, Stefan Förster, and Wolf Widdra — Martin-Luther-Universität Halle-Wittenberg, Halle, Germany

BiFeO₃ is one of the very rare single-phase magnetoelectric multiferroics and shows ferroelectric and antiferromagnetic behavior at room temperature, whereas BaTiO₃ exhibits only a ferroelectric order. The surface domain structure of BaTiO₃(001) and BiFeO₃(001) has been studied by Laser-excited photoelectron emission microscopy (PEEM) under UHV conditions. The PEEM images of BaTiO₃ allow for discrimination of three domain types by their different photoemission yields. In wavelength dependent measurements the ferroelectric a and c domains exhibit approx. 100 meV different photoemission onsets. Based on the markedly high surface sensitivity of PEEM a specific ferroelectric surface domain structure on-top of a paraelectric bulk is observed in a temperature window up to 100 K above the bulk Curie temperature.

For the multiferroic BiFeO₃(001) surface we demonstrate imaging of the ferroelectric and the antiferromagnetic domain structure by PEEM using threshold excitation with linearly and circularly polarized laser light. The specific polarization dependencies will be discussed.