Regensburg 2019 – wissenschaftliches Programm

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 11: Multiferroics and Magnetoelectric coupling I (joint session MA/KFM)

KFM 11.6: Vortrag

Dienstag, 2. April 2019, 15:30–15:45, H37

Temperature- and pressure-dependent optical measurements on the photo-response in multiferroic BiFeO₃ — •Fabian Meggle¹, Jihaan Ebad-Allah^1,2, Michel Viret³, Jens Kreisel^4,5, and Christine Kuntscher¹ — ¹Experimentalphysik II, Universität Augsburg, 86159 Augsburg, Germany — ²Department of Physics, Tanta University, 31527 Tanta, Egypt — ³Service de Physique de l’État Condenseé, SPEC, CEA Saclay, CNRS, Université Paris-Saclay, 91191 Gif sur Yvette, France — ⁴Physics and Materials Science Research Unit, University of Luxembourg, 4422 Belvaux, Luxembourg — ⁵Department Materials Research and Technology, Luxembourg Institute of Science and Technology, 41 Rue du Brill, 4422 Belvaux, Luxembourg

BiFeO₃ exhibits three absorption features in the optical transmission spectrum between 1.0 and 2.2 eV during laser illumination.¹ These features were ascribed to excitons, which are proposed to be relevant for the ultrafast photostriction effect in BiFeO₃.² We studied the impact of low temperature and high pressure on the photo-induced features by using optical spectroscopy. Our temperature-dependent findings suppose a possible coupling between absorption features and lattice vibrations, whereas the spin degree of freedom might be also involved. The pressure-dependent measurements show a vanishing of the absorption features above 3.5 GPa, where BiFeO₃ is reported to undergo a phase transition from polar to a non-ferroelectric phase.^{3 1}Burkert et al., Appl. Phys. Lett. 109, 182903 (2016); ²Schick et al., Phys. Rev. Lett. 112, 97602 (2014); ³Belik et al., Chem. Mater. 21, 3400 (2009)