Advertisement

Journal of Materials Science

, Volume 32, Issue 21, pp 5817–5823 | Cite as

Frequency dependence of the complex impedances and dielectric behaviour of some Mg-Zn ferrites

  • M. H ABDULLAH
  • A. N YUSOFF
Article

Abstract

Complex impedances of some magnesium-zinc ferrites, MgxZn1-xFe2O4 (x=0.4, 0.5, 0.6 and 0.7), in the frequency range of 1 mHz-10 MHz were measured at 300 K. The complex-plane impedance spectrum from each sample indicates that the capacitive and the resistive properties of the materials are mainly attributed to the processes that associated with the bulk (grain) and the grain boundary. A low-frequency dispersion (LFD) and a negative capacitance regions are also observed at low frequencies. A small series resistance of about the same value for all samples is also observed. The bulk and the grain boundary components are analysed by assuming a two-layer leaky capacitor. The simulated complex impedances using the Cole-Cole expression are in agreement with the measured values. The dielectric properties of the materials are attributed to the interfacial polarization and LFD at low frequencies and the orientational polarization at high frequencies. These properties result in the dielectric loss which composed of a Debye-like loss peak at high frequency end and a strong LFD below 1 Hz. Both regions exhibit universality with regard to the power-law relation between the dielectric loss (ε″r or χ″) and frequency as given by ε″r∝ωn-1, where n=0.14 and n=0.02, respectively. The exponent is marginally negative, n=−0.03, in the region of negative capacitance below 3–4 mHz. The variations of the above properties and the characteristic parameters for different compositions of the Mg-Zn ferrites are discussed.

Keywords

Ferrite Dielectric Loss Complex Impedance Interfacial Polarization Cole Expression 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    W. I. ARCHER and R. D. ARMSTRONG, Electrochemistry 7 (1979) 157.CrossRefGoogle Scholar
  2. 2.
    S. P. S. BADWAL, in ‘‘Solid state ionic devices’’ (World Scientific, Singapore, 1988), p. 125.Google Scholar
  3. 3.
    T. STRATON, A. MACHALE, D. BUTTON and H. L. TURNER, in ‘‘Electronic materials’’ edited by N. B. Hannay and U. Colombo (Plenum Press, New York, 1979) p. 71.Google Scholar
  4. 4.
    M. L. BAYARD, in ‘‘Proceedings of the International Conference on Fast Ion Transport in Solids, Electrodes and Electrolytes’’ 2125 May 1979, Lake Geneva, Wisconsin (North-Holland, New York, 1979) p. 479.Google Scholar
  5. 5.
    Y. C. YEH and T. Y. TSENG, J. Mater. Sci. 24 (1989) 2739.CrossRefGoogle Scholar
  6. 6.
    M. H. ABDULLAH and A. N. YUSOFF, J. Alloys Compounds 233 (1996) 129.CrossRefGoogle Scholar
  7. 7.
    J. R. MACDONALD, J. Chem. Phys. 61 (1974) 3977, and references therein.CrossRefGoogle Scholar
  8. 8.
    A. K. JONSCHER, Nature 250 (1974) 191.CrossRefGoogle Scholar
  9. 9.
    Idem., Colloid Polym. Sci. 253 (1975) 231.CrossRefGoogle Scholar
  10. 10.
    Idem., Nature 253 (1975) 717.CrossRefGoogle Scholar
  11. 11.
    Idem., ibid. 256 (1975) 566.CrossRefGoogle Scholar
  12. 12.
    Idem., ibid. 267 (1977) 673.CrossRefGoogle Scholar
  13. 13.
    N. E. HILL, W. E. VAUGHAN, A. H. PRICE and M. DAVIES, ‘‘Dielectric properties and molecular behaviour’’ (Van Nostrand-Reinhold Co., New York, 1969) p. 47.Google Scholar
  14. 14.
    V. P. MIROSHKIN, V. V. PASSYNKOV and K. PERZYNSKY, Acta Phys. Polonica A77 (1990) 715.Google Scholar
  15. 15.
    P. V. REDDY and T. S. RAO, J. Less-Common Metals 105 (1985) 63, and the references therein.CrossRefGoogle Scholar
  16. 16.
    J. C. ANDERSON, ‘‘Dielectric’’ (Chapman & Hall Ltd., London, 1964) p. 96.Google Scholar
  17. 17.
    J. SEYMOUR, ‘‘Electronic devices and components’’ (ELBS, London, 1984) p. 421Google Scholar
  18. 18.
    S. S. SURYAVANSHI, S. R. PATIL and S. R. SAWANT, J. Less-Common Metals 168 (1991) 16.CrossRefGoogle Scholar
  19. 19.
    K. L. NGAI, Comments Solid State Phys. 9 (1979) 127.Google Scholar
  20. 20.
    K. L. NGAI, A. K. JONSCHER and C. T. WHITE, Nature 277 (1979) 185.CrossRefGoogle Scholar
  21. 21.
    K. L. NGAI and C. T. WHITE, Phys. Rev. B20 (1979) 2475.CrossRefGoogle Scholar
  22. 22.
    K. L. NGAI, ibid. B22 (1980) 2066.CrossRefGoogle Scholar
  23. 23.
    L. A. DISSADO and R. M. HILL, Phil. Mag. B41 (1980) 625.CrossRefGoogle Scholar
  24. 24.
    Idem., J. Mater. Sci. 16 (1981) 1410.CrossRefGoogle Scholar
  25. 25.
    A. K. JONSCHER, ‘‘Dielectric relaxation in solids’’ (Chelsea Dielectrics Press Ltd., London, 1983).Google Scholar
  26. 26.
    Idem., J. Mater. Sci. 30 (1995) 2491.CrossRefGoogle Scholar
  27. 27.
    Idem., ‘‘Universal relaxation law’’ (Chelsea Dielectric Press Ltd., London, 1995).Google Scholar

Copyright information

© Chapman and Hall 1997

Authors and Affiliations

  • M. H ABDULLAH
    • 1
  • A. N YUSOFF
    • 1
  1. 1.Physics Department, Faculty of Physical and Applied SciencesUniversiti Kebangsaan MalaysiaBangi SelangorMalaysia

Personalised recommendations