Combustion synthesis and properties of strontium substituted lanthanum manganites La_1–xSr_xMnO₃ (0≤x≤0.3)

Abstract

Strontium substituted lanthanum manganites La_1–xSr_xMnO₃ (x=0, 0.1, 0.16, 0.2 and 0.3) have been prepared by a solution combustion process using lanthanum nitrate, strontium nitrate and manganese nitrate as oxidizers and oxalyl dihydrazide as fuel at 300 °C in a pre-heated muffle furnace. As-formed lanthanum manganites are X-ray crystalline showing cubic symmetry. The cubic LaMnO₃ with 36% Mn⁴⁺ changes to a rhombohedral phase (Mn⁴⁺=28%) on calcination at 1000 °C. The surface area and average agglomerated particle size of the as-formed manganites are in the range 12–19 m² g^–1 and 5.4–8.0 µm, respectively. Sintering, thermal expansion and dc electrical conductivity measurements of La(Sr)MnO₃ have been carried out. Strontium substituted lanthanum manganites achieve >80% theoretical density after sintering at 1350 °C for 4 h and the percentage theoretical density decreases with increasing strontium content. The thermal expansion coefficient of La(Sr)MnO₃ increases with increasing Sr²⁺ content and La_0.84Sr_0.16MnO₃ shows a highest conductivity value of 202 S cm^–1 at 900 °C in air.

References

1. N. Q. Minh, J. Am. Ceram. Soc., 1993, 76, 563.
2. A. Hammouche, E. Siebert and A. Hammou, Mater. Res. Bull., 1989, 24, 367.
3. K. Kamata, T. Nakajuma, T. Hayashi and T. Nakamura, Mater. Res. Bull., 1978, 13, 49.
4. G. V. Subbarao, B. M. Wanklyn and C. N. R. Rao, J. Phys. Chem. Solids, 1971, 32, 345.
5. G. H. Jonker, J. Phys. Chem. Solids, 1959, 9, 165.
6. D. W. Johnson Jr, P. K. Gallagher, F. Schrey and W. W. Rhodes, Am. Ceram. Soc. Bull., 1976, 55, 520.
7. G. H. Jonker and J. H. Van Santen, Physica, 1950, 16, 599.
8. V. Ferris, L. Brohan, M. Ganne and M. Tournoux, Eur. J. Solid State Inorg. Chem., 1995, 32, 131.
9. M. Hervieu, Eur. J. Solid State Chem., 1995, 32, 79.
10. J. A. M. van Roosmalen and E. H. P. Cordfunke, J. Solid State Chem., 1994, 110, 106.
11. J. H. Kuo, H. U. Anderson and D. M. Sparlin, J. Solid State Chem., 1990, 87, 55.
12. M. Kertesz, I. Riess, D. S. Tannhauser, R. Langpage and F. J. Rohr, J. Solid State Chem., 1982, 42, 125.
13. G. H. Jonker and J. H. Van Santen, Physica, 1950, 16, 377.
14. H. Taguchi, D. Matsuda, M. Nagao, K. Tanihata and Y. Miyamoto, J. Am. Ceram. Soc., 1992, 75, 201.
15. M. S. G. Baythoun and F. R. Sale, J. Mater. Sci., 1982, 17, 2757.
16. S. A. Prokudina, Ya. S. Rubinchik and M. M. Pavlyuchenko, Inorg. Mater., 1974, 10, 416.
17. K. C. Patil, Bull. Mater. Sci., 1993, 16, 533.
18. S. S. Manoharan and K. C. Patil, J. Solid State Chem., 1993, 102, 267.
19. H. Klug and L. Alexander, X-ray Diffraction Procedures, John Wiley, New York, 1962.
20. M. Verelst, N. Rangavittal, C. N. R. Rao and A. Rousset, J. Solid State Chem., 1993, 104, 74.
21. R. Mahendiran, R. Mahesh, A. K. Raychaudri and C. N. R. Rao, Pramana J. Phys., 1995, 44, 393.
22. R. Mahesh, K. R. Kannan and C. N. R. Rao, J. Solid State Chem., 1995, 114, 294.
23. A. Wold and R. J. Arnott, J. Phys. Chem. Solids, 1959, 9, 176.
24. B. C. Tofield and W. R. Scott, J. Solid State Chem., 1974, 10, 183.
25. J. A. M. van Roosmalen, E. H. P. Cordfunke and J. P. P. Huijsmans, Solid State Ionics, 1993, 66, 285.
26. T. Ishihara, T. Kudo, H. Matsuda and Y. Takita, J. Am. Ceram. Soc., 1994, 77, 1682.
27. J. Tanaka, M. Umehara, S. Tamura, M. Tsukioka and S. Ehara, J. Phys. Soc. Jpn., 1982, 51, 1236.
28. D. P. Karim and A. T. Aldred, Phys. Rev. B, 1979, 20, 2255.
29. J. A. M. van Roosmalen, J. P. P. Huijsmans and L. Plomp, Solid State Ionics, 1993, 66, 279.