Dresden 2014 – scientific programme

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KR: Fachgruppe Kristallographie

KR 5: Multiferroics II (MA jointly with DF, DS, KR, TT)

KR 5.3: Talk

Wednesday, April 2, 2014, 10:00–10:15, HSZ 04

Behaviour of Raman modes in BiFeO₃ epitaxial thin films with respect to azimuthal orientation — •Andreas Talkenberger¹, Cameliu Himcinschi¹, Ionela Vrejoiu^2,3, Florian Johann², and Jens Kortus¹ — ¹TU Bergakademie Freiberg, Institute of Theoretical Physics, Leipziger Str. 23, D-09596 Freiberg, Germany — ²Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle, Germany — ³Max Planck Institute for Solide State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany

BiFeO₃ (BFO) is an interesting candidate for multiferroic applications. In this work we focus on the Raman spectroscopic investigation of epitaxially grown thin films of BFO by pulsed laser deposition on different substrates, belonging to the group of scandates (DyScO₃, SmScO₃, GdScO₃). The Raman spectra were recorded using the 442 nm emission line of a He-Cd laser. Some phonon modes show changes in the position, full width at half maximum (FWHM) and intensity depending on the azimuthal angle. We found a 90 degree periodicity of the peak position and of the FWHM for particular modes. For both parallel and crossed polarisation the four maxima in positions correspond to the minima in FWHM. Such a behaviour can be explained considering a twin family of domains with a very well defined orientation to each other. Our results are supported by piezoresponse-force microscopy and X-ray diffraction measurements as well.