resumo
Bi1-xLaxFeO3 and Bi1-xPrxFeO3 ceramics of the compositions near the morphotropic phase boundary have been studied by X-ray and neutron diffraction techniques and differential thermal analysis. The structural phases characterized by the long-range polar, antipolar, and nonpolar ordering as well as the phase coexistence regions have been identified using the diffraction data depending on the dopant concentration and temperature. As a result of these studies the three phase region has been observed for the Pr-doped compounds and the phase diagrams have been constructed. The detailed evolution of the structural parameters permitted to itemize the factors affecting the structural phase transitions and clarify the origin of the enhanced electromechanical properties in these materials. The performed structural analysis disclosed different character of the chemical bonds in the La-and Pr-doped BiFeO3 compounds. Further, the role of the rare-earth ions in the covalency of the chemical bonds is discussed.
palavras-chave
EARTH-SUBSTITUTED BIFEO3; SOLID-SOLUTIONS; DOPED BIFEO3; NEUTRON-DIFFRACTION; PHASE-TRANSITIONS; CRYSTAL-STRUCTURE; BOUNDARY
categoria
Materials Science
autores
Karpinsky, DV; Troyanchuk, IO; Tovar, M; Sikolenko, V; Efimov, V; Efimova, E; Shur, VY; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Jubilado
Dzmitry Karpinski (Karpinsky)
Bolseiro de pós-DoutoramentoProjectos
agradecimentos
The authors would like to acknowledge the financial support from the FCT (grants no. SFRH/BPD/42506/2007, EXPL/CTM-NAN/1611/2013, and PEst-C/CTM/LA0011/2013) and from RFFI (grant no. 13-02-90903). This research project has been supported by the European Commission under the 7th Framework Programme through the