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X-ray photoelectron spectroscopy of nickel manganese oxide thermistors

Published online by Cambridge University Press:  31 January 2011

T. Hashemi
Affiliation:
Applied Physics, Department of Physics, University of Durham, Durham DH1 3LE, United Kingdom
A.W. Brinkman
Affiliation:
Applied Physics, Department of Physics, University of Durham, Durham DH1 3LE, United Kingdom
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Abstract

The major problem in the NiMn2O4 system has been the determination of the valencies and the cation distribution between the two sublattices of the inverse spinel structure, in which both manganese and nickel can adopt more than one valence state. X-ray photoelectron spectroscopy (XPS) was used to elucidate the valence distribution of the manganese and nickel ions. The results showed that identification of the three Mn and two Ni species in the nickel manganite phase is possible, enabling the validity of crystal structure configurations, proposed in the literature, to be assessed. A small amount of copper, added as CuO to the system, was found to be present in both monovalent and divalent states, the Cu+ ions inducing the creation of the large amount of tetravalent Mn observed. This led to a larger number of sites for electron hopping, the mechanism of conduction, and consequently the electrical conductivity of the Cu doped material is much higher than the undoped NiMn2O4.

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Articles
Copyright
Copyright © Materials Research Society 1992

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References

1.Sheflel, I. T., Zaslavski, A. I., Kurling, E. V., and Teskter, G. N., Sov. Phys. Solid State 3, 1979 (1962).Google Scholar
2.Larson, E. G., Arnott, R. J., and Wickham, D. G., J. Phys. Chem. Solids 23, 1771 (1962).CrossRefGoogle Scholar
3.Kshirsagar, S. T., J. Phys. Soc. Jpn. 27, 1164 (1969).CrossRefGoogle Scholar
4.Bhandage, G. T. and Keer, H. V., J. Phys. C: Solid State Phys. 9, 1325 (1976).CrossRefGoogle Scholar
5.Braber, V. A. M. and Terhell, J. C. J. M., Phys. Status Solidi (a) 69, 325 (1962).CrossRefGoogle Scholar
6.Villers, G. and Buhl, R., C. R. Acad. Sci. Paris 260, 3406 (1965).Google Scholar
7.Boucher, B., Buhl, R., and Perrin, M., Acta Cryst. B 25, 2356 (1969).CrossRefGoogle Scholar
8.Azimi-Nam, S., Golestani-Fard, F., and Hashemi, T., J. Electronic Mater. 16, 133 (1987).CrossRefGoogle Scholar
9.Islam, M. S. and Catlow, C. R. A., Phys. Chem. Solids 49, 119 (1988).CrossRefGoogle Scholar
10.Macklen, E. D., J. Phys. Chem. Solids 47, 1073 (1986).CrossRefGoogle Scholar
11.O'Keeffe, M., J. Phys. Chem. Solids 21, 172 (1961).CrossRefGoogle Scholar
12.Braber, V. A. M., van Setten, F. M., and Knapen, P. S. A., J. Solid State Chem. 49, 93 (1983).CrossRefGoogle Scholar
13.Carver, J. C., Schweizer, G. K., and Carlson, T. A., J. Chem. Phys. 57, 973 (1972).CrossRefGoogle Scholar
14.Vernon, G. E., Stucky, G., and Carlson, T. A., Inorg. Chem. 15, 278 (1976).CrossRefGoogle Scholar
15.Foord, J. S., Jackman, R. B., and Allen, G. C., Philos. Mag. A 49, 657 (1984).CrossRefGoogle Scholar
16.Oko, M. and Hirokawa, H., J. Electron Spectrosc. 7, 465 (1975).CrossRefGoogle Scholar
17.Rao, C. N., Sarma, D. D., and Hedge, M. S., Proc. Roy. Soc. A 367, 239 (1979).Google Scholar
18.Wurtheim, G. K., Hüfner, S., and Guggenheim, H. J., Phys. Rev. B 7, 556 (1973).CrossRefGoogle Scholar
19.Sinha, A. O. B., Sanjana, N. R., and Biwas, A. B., Acta Cryst. 10, 439 (1957).CrossRefGoogle Scholar
20.Balzer, P. K. and White, G. J., J. Appl. Phys. 29, 445 (1958).CrossRefGoogle Scholar
21.Ng, K. T. and Hercules, D. M., J. Phys. Chem. 80, 2094 (1976).CrossRefGoogle Scholar
22.Chadwick, D. and Hashemi, T., Surf. Sci. 89, 646 (1979)CrossRefGoogle Scholar