Berlin 2015 – wissenschaftliches Programm

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KR: Fachgruppe Kristallographie

KR 3: Poster Session on Ferroic Domain Walls - Multiferroics (DF jointly with KR, MA, TT)

KR 3.15: Poster

Montag, 16. März 2015, 19:00–21:00, Poster C

Influence of piezoelectric induced strain on the Raman spectra of BiFeO₃ films — •Cameliu Himcinschi¹, Andreas Talkenberger¹, Jens Kortus¹, Alexander Schmid², Er-Jia Guo^{3, 4}, and Kathrin Dörr^{3, 4} — ¹TU Bergakademie Freiberg, Institute of Theoretical Physics, D-09596 Freiberg, Germany — ²TU Bergakademie Freiberg, Institute of Applied Physics, D-09596 Freiberg, Germany — ³Institute for Physics, Martin-Luther-University Halle-Wittenberg, 06099 Halle, Germany — ⁴Institute for Metallic Materials, IFW Dresden, 01069 Dresden, Germany

BiFeO₃ epitaxial thin films were deposited on piezoelectric 0.72Pb(Mg_1/3Nb_2/3)O₃-0.28PbTiO₃ (PMN-PT) substrates with a conductive buffer layer (La_0.7Sr_0.3MnO₃, or SrRuO₃) using pulsed laser deposition. The calibration of the strain values induced by the applied voltage on the piezoelectric PMN-PT substrates was realised using X-Ray Diffraction measurements. Raman spectra monitoring as a function of the applied voltage (and hence strain) was performed in resonant conditions, using the 442 nm line of a HeCd laser. The piezoelectric induced strain in the BiFeO₃ films causes shifts in the phonon position. The method of piezoelectrically induced strain allows to obtain a quantitative correlation between strain and the shift of the Raman-active phonons, ruling out the influence of extrinsic factors, as growth conditions, crystalline quality of substrates, or film thickness.
This work is supported by the German Research Foundation DFG HI 1534/1-2.