Structure and properties of Bi^sub 2^Ti^sub 2^O^sub 7^ pyrochlore type phase stabilized by lithium

A study of the Li2O - Bi2O3 - TiO2 ternary system evidenced a Bi2Ti2O7 pyrochlore phase in a large range of composition, centered on (Li1/2Bi1/2)TiO3 (LBT). This composition led to a pyrochlore phase stable up to 1100 °C, while pure Bi2Ti2O7 phase has been reported as metastable, with decomposition...

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Bibliographic Details
Published in:Journal of alloys and compounds 2018-01, Vol.732, p.178
Main Authors: Lelievre, Jerome, Marchet, Pascal
Format: Article
Language:English
Subjects:
Bismuth oxides
Bismuth titanate
Bismuth trioxide
Dielectric properties
Diffraction
Electric properties
Electrical properties
Lithium
Lithium oxides
Neutron diffraction
Studies
Ternary systems
Thermal stability
Titanium oxides
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Summary:A study of the Li2O - Bi2O3 - TiO2 ternary system evidenced a Bi2Ti2O7 pyrochlore phase in a large range of composition, centered on (Li1/2Bi1/2)TiO3 (LBT). This composition led to a pyrochlore phase stable up to 1100 °C, while pure Bi2Ti2O7 phase has been reported as metastable, with decomposition temperature around 600 °C. According to previous studies, this pyrochlore phase was not obtained without lithium and here only a few percent of lithium was necessary for stabilization. The structural study, performed by neutron diffraction, evidenced a cubic Fd... structure (a = 10.317 Å), similar to the one of "pure" Bi2Ti2O7 pyrochlore phase. The Li-ion is probably located on the Bi-site and is responsible for the stabilization of the pyrochlore structure. The electrical properties of the LBT composition were studied and appeared as very similar to the one of "pure" Bi2Ti2O7. Because of its large thermal stability range, this pyrochlore phase appears to be a promising material for dielectric or tunability applications.(ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0925-8388
1873-4669