resumo
We report on the discovery of an isothermal structural transition observed in Bi1-xLaxFeO3 (0.17 <= x <= 0.19) ceramics. At room temperature, an initially pure polar rhombohedral phase gradually transforms into a pure antipolar orthorhombic one. The polar phase can be recovered by annealing at T > 300 degrees C. In accordance with neutron powder diffraction data, an inverse isothermal antipolar-polar transition takes place at T > 300 degrees C, where the polar phase becomes more stable. The antipolar phase is characterized by a weak ferromagnetic state, whereas the polar phase has been obtained in a mixed antiferromagnet-weak ferromagnet state. The relatively low external pressure induces polar-antipolar transition, but there is no evidence of electric-field-driven antipolar-polar transition. The observed large local piezoelectric response is associated with structural instability of the polar phase, whereas local multistate piezoelectric loops can be related to the domain wall pinning effect.
palavras-chave
BISMUTH FERRITE; BEHAVIOR; BIFEO3
categoria
Physics
autores
Troyanchuk, IO; Karpinsky, DV; Bushinsky, MV; Khomchenko, VA; Kakazei, GN; Araujo, JP; Tovar, M; Sikolenko, V; Efimov, V; Kholkin, AL
nossos autores
Andrei Kholkin
Investigador Jubilado
Dzmitry Karpinski (Karpinsky)
Bolseiro de pós-Doutoramentoagradecimentos
The authors would like to acknowledge the financial support of the BRFFI (Grant Nos. T10R-119 and F09K-043), the Foundation for Science and Technology of Portugal (FCT) (the Ciencia 2008 and Ciencia 2007 programs and Grant No. SFRH/BPD/42506/2007). This research project has also been partly supported by the European Commission under the Seventh Framework Programme through the Key Action: Strengthening the European Research Area, Research Infrastructures [Contract No. 226507 (NMI3)].