Cuspidine-Like Compounds Ln4[Ga2(1-x)Ge2xO7+x
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- 作者：Anthony Chesnaud ; Olivier Joubert ; Maria Teresa Caldes ; Samrat Ghosh ; Yves Piffard ; and Luc Brohan
- 刊名：Chemistry of Materials
- 出版年：2004
- 出版时间：December 14, 2004
- 年：2004
- 卷：16
- 期：25
- 页码：5372 - 5379
- 全文大小：601K
- 年卷期：v.16,no.25(December 14, 2004)
- ISSN：1520-5002
文摘
The Ln4[Ga2(1-x)Ge2xO7+x
1-x]O2 (Ln = La, Nd, Gd; x 
0.4) compounds have been preparedfirst by solid-state reaction and then by a new regenerative sol-gel method which allowstheir sintering. They exhibit a Cuspidine-like structure. Upon substituting Ge4+ for Ga3+,the Cuspidine structure is maintained up to x = 0.4. For x 
0.15 a 1D modulation of thestructure was observed and analyzed as driven by composition. The Ge4+ substitution forGa3+ with concomitant filling of oxygen vacancies is beneficial to the anionic conductivitywhich increases rather regularly with x to reach 10-3 S/cm at 800 
C for x = 0.4 and Ln =Nd. Conductivity measurements on Ln4[Ga2(1-x)Ge2xO7+x1-x]O2 (Ln = La, Nd, Gd) compoundswith a fixed Ge content (x = 0.2) show a clear increase of the activation energy when theionic radii of the Ln3+ cation decreases. La and Nd compounds exhibit similar conductivities,significantly larger than that of the Gd counterpart.
1-x]O2 (Ln = La, Nd, Gd; x 0.4) compounds have been preparedfirst by solid-state reaction and then by a new regenerative sol-gel method which allowstheir sintering. They exhibit a Cuspidine-like structure. Upon substituting Ge4+ for Ga3+,the Cuspidine structure is maintained up to x = 0.4. For x 0.15 a 1D modulation of thestructure was observed and analyzed as driven by composition. The Ge4+ substitution forGa3+ with concomitant filling of oxygen vacancies is beneficial to the anionic conductivitywhich increases rather regularly with x to reach 10-3 S/cm at 800 C for x = 0.4 and Ln =Nd. Conductivity measurements on Ln4[Ga2(1-x)Ge2xO7+x1-x]O2 (Ln = La, Nd, Gd) compoundswith a fixed Ge content (x = 0.2) show a clear increase of the activation energy when theionic radii of the Ln3+ cation decreases. La and Nd compounds exhibit similar conductivities,significantly larger than that of the Gd counterpart.