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MM: Fachverband Metall- und Materialphysik

MM 15: Poster Session

MM 15.72: Poster

Montag, 11. März 2013, 18:00–20:00, Poster E

Transmission electron microscopy study of defects in BiFeO3 thin films — •Hakan Deniz, Akash Bhatnagar, Eckhard Pippel, Marin Alexe, and Dietrich Hesse — Max-Planck Institute of Microstructure Physics, Weinberg 2, D-06120, Halle (Saale), Germany

A wide class of oxide materials with perovskite crystal structure has been in the focus of intense research efforts lately due to fascinating properties they posses; such as ferroelectricity, colossal magnetoresistance, superconductivity, etc. Bismuth ferrite (BiFeO3) among them is the leading contender in the research of multiferroic compounds with both ferroic order parameters well above room temperature. It is of vital importance to grow defect-free high quality thin films in order to better understand/correlate structure-property relationships of these materials. Single crystal BiFeO3 thin films grown by pulsed laser deposition on scandate oxide substrates (TbScO3, GdScO3, etc.) have been investigated in high-resolution TEM (HRTEM) and high angle annular dark field scanning TEM (HAADF-STEM). Defects having a layered structure, similar to bismuth-oxide layered perovskites, with a chemical composition different from the rest of the film have been observed. Fast Fourier transform (FFT) analysis and image processing were used to elucidate the nature of these defects. They correspond to a new unknown phase in BiFeO3 thin films. Understanding their origin will help to grow higher quality virtually defectless films. This work is supported by the FP7 project IFOX.