Structure characterization of triple perovskites and related systems by transmission electron microscopy
22 February 2017
UAntwerpen, Campus Groenenborger, U0.24 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger
Organization / co-organization:
Department of Physics
Robert Paria Sena
Joke Hadermann & Gustaaf Van Tendeloo
PhD defence Robert Paria Sena - Faculty of Science, Department of Physics
During my Ph.D. research, I have investigated the structure of specific perovskite based oxides in order to establish the correlation between the structure and the electrical and magnetic properties. The final goal of our study is to design new compounds with a potential for applicable properties, such as for example relaxor ferromagnetism.
The synthesis itself is not part of the Ph.D. work; the materials have been synthesized by collaborating research groups at the University of Oxford, New Jersey State University and Taras Shevchenko National University of Kyiv; also the bulk diffraction techniques were performed by our collaborators. Within my Ph.D. work itself, the crystal structures have been solved, using a combination of transmission electron microscopy techniques, including selected area electron diffraction (SAED) combined with real space imaging using different techniques such as high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field scanning transmission electron microscopy (ABF-STEM) and energy dispersive X-ray spectroscopy-STEM (EDX-STEM).
Based on these studies, models have been proposed and refined for different perovskite compounds. With these models we have tried to explain the variations in the properties of the samples and we have compared them to similar materials. The disclosed relations have rendered fundamental knowledge, applicable for the optimization of the properties of the investigated materials as well as of related perovskite materials.