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Structure and Microstructure Study of Oxides of the La2/3-xLi3xTiO3-family

Published online by Cambridge University Press:  01 February 2011

Ulises Amador
Affiliation:
[email protected], Universidad San Pablo-CEU, Madrid, Spain
Susana García-Martín
Affiliation:
[email protected], Universidad Complutense, Inorganica I, Madrid, Spain
Ainhoa Morata-Orrantia
Affiliation:
[email protected], Universidad Complutense, Inorganica I, Madrid, Spain
Juan Rodríguez-Carvajal
Affiliation:
[email protected], ILL, Grenoble, France
Miguel Ángel Alario-Franco
Affiliation:
[email protected], Universidad Complutense, Inorganica I, Madrid, Spain
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Abstract

Materials of the La2/3-xLi3xTiO3–family have been studied by selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), powder synchrotron X-ray diffraction and powder neutron diffraction. HRTEM showed that the materials have a complex domain-microstructure. The size and shape of the domains have been obtained from synchrotron X-ray diffraction data; besides, other extended defects such as strains and compositional fluctuations have been detected. The complementary use of local (SAED and HRTEM) and average (SXRD and NPD) techniques have allowed us to propose a model to refine the crystal structure of these oxides also accounting for their microstructure. All these materials have a perovskite-related structure with a diagonal unit cell (≈√2ap x √2ap x 2ap) as a consequence of the tilting of the TiO6 octahedra. Ordering of lanthanum and lithium ions and vacancies along the 2ap-axis, as well as displacements of titanium ions from the centre of the octahedra, have been determined. The Li+ ions present a distorted square planar coordination and are located in interstitial positions of the structure, which could explain the very high ionic conductivity of this type of materials. The lithium conductivity depends on the oxide composition and its crystal microstructure, which varies with the thermal treatment of the sample.

Type
Research Article
Copyright
Copyright © Materials Research Society 2009

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References

REFERENCES

1. Newnham, R., Structure Property Relations, (Springer Verlag, 1974).Google Scholar
2. Stramare, S., Thangadurai, V., Weppner, W., Chem. Mater. 15, 3974, (2003)Google Scholar
3. Inaguma, Y., Liquan, C., Itoh, M., Nakamura, T., Solid State Commun., 86 (10), 689, (1993).Google Scholar
4. García-Martín, S., Alario-Franco, M.A., Ehrenberg, H., Rodríguez-Carvajal, J., Amador, U., J. Am. Chem. Soc. 126, 3587, (2004).Google Scholar
5. García-Martín, S., Morata-Orrantía, A., Alario-Franco, M.A., Rodríguez-Carvajal, J., Amador, U., Chem. Eu. J., 13(19), 5617, (2007).Google Scholar
6. García-Martín, S., Amador, U., Morata-Orrantia, A., Rodríguez-Carvajal, J., Alario-Franco, M.A., Anorg, Z.. Allg. Chem., (submmited).Google Scholar
7. Rodríguez-Carvajal, J., Physica B 19, 55 (1993). See also a recent report in CPD of IUCr, Newsletter 26, 12–19 (2001), available at http://www.iucr.org/iucr-top/comm/cpd/Newsletters/. The program and manual can be found at http://www.ill.eu/sites/fullprof/index.html Google Scholar
8. Langford, J.I., in Defect and Microstructure Analysis by Diffraction IUCr Monographs on Crystallography 10, (Ed. Snyder, P., Fiala, F. and Bunge, H., Oxford University Press, Oxford, 1999), pp. 5981;Google Scholar
Louër, D., Defect and Microstructure Analysis by Diffraction IUCr Monographs on Crystallography 10, (Ed. Snyder, P., Fiala, F. and Bunge, H., Oxford University Press, Oxford, 1999), pp. 671697.Google Scholar
9. Morata-Orrantia, A., García-Martín, S., Alario-Franco, M. A., Chem. Mater., 15, 363, (2003).Google Scholar
10. Morata-Orrantia, A., García-Martín, S., Morán, E., Alario-Franco, M.A., Chem. Mater. 14, 2871, (2002).Google Scholar
11. Rial, C., Morán, E., Alario-Franco, M.A., Amador, U., Andersen, N., Physica C, 278, 122, (1997).Google Scholar
12. Warren, B.E., X-ray Diffraction, (Ed. Dover Publications Inc., N.Y., USA, 1990).Google Scholar
13. Williamson, G.K. and Hall, W.H., Acta. Met., 1, 22, (1953).Google Scholar
14. Halder, N.C. and Wagner, C.N.J., Adv. X-Ray Anal., 9, 91, (1966).Google Scholar
15. Wilson, A.J.C., Mathematical Theory of X-ray Powder Diffractometry, (Ed. Philips Technical Library, Eindhoven, Holland, 1963).Google Scholar
16. Thomas, N. W., Acta Cryst. B, 52, 16, (1996).Google Scholar
17. Woodward, P. M., Acta Cryst. B, 53, 32, (1997).Google Scholar
18. Woodward, P. M., Acta Cryst. B, 53, 44, (1997).Google Scholar
19. Howard, C. J. and Stokes, H.T., Acta Cryst. B 54, 782, (1998).Google Scholar
20. Yashima, M., Itoh, M., Inaguma, Y., Morii, Y., J. Am. Chem. Soc. 127, 3491, (2005).Google Scholar
21. Alonso, J. A., Sanz, J., Santamaría, J., León, C., Várez, A., Fernández-Díaz, M. T., Angew. Chem. Int. Ed. 39(3), 619, (2000).Google Scholar
22. Fourquet, J. L., Duroy, H., Crosnier-López, M. P., J. Solid State Chem. 127, 283, (1996).Google Scholar