Journal of Electroceramics

, Volume 22, Issue 1–3, pp 227–232 | Cite as

Preparation, thermal stability and permeability behavior of substituted Z-type hexagonal ferrites for multilayer inductors

  • S. Kračunovska
  • J. Töpfer


Co2Z-type hexagonal ferrites with iron excess Ba3Co2 − x Fe24 + x O41 (0 ≤ x ≤ 0.8) and deficiency Ba3Co2 + y Fe24 − y O41 (0 ≤ y ≤ 0.6) were prepared by an oxalate coprecipitation technique. This synthesis route leads to almost single phase Z-type ferrites for x = 0 after calcination and sintering at 1330 °C. The Z-type formation is enhanced for x > 0 and single phase ferrites are obtained for 0.4 ≤ x ≤ 0.8. The permeability of Z-type ferrites varies with composition x: Maximum permeability of μ′ = 28 is observed for 0.4 ≤ x ≤ 0.6 for samples sintered at 1330 °C. The frequency dispersion shows broad peaks of μ″ stretching from 200 MHz to >1 GHz. For iron deficient samples 0 ≤ y ≤ 0.6 multi-phase mixtures were obtained. For Ag-based multilayer inductor applications sintering at 950 °C is required. Co2Z ferrites with Fe excess are not stable at this temperature as demonstrated by XRD. The permeability of samples sintered at 950 °C is drastically reduced to μ′ = 3. This demonstrates that these materials are not able to provide sufficient permeability for multilayer inductors for high-frequency operations since they are not compatible with the low temperature ceramic cofiring technology.


Soft ferrites Co2-Z hexagonal ferrites Permeability 


75.50 Gg 81.20 Ev 81.40 Rs 



The authors thank the Bundesministerium für Bildung und Forschung (Germany) for financial support (grant 03WKF22E). We acknowledge the contributions of Mrs. M. Friedrich (FHJ) for SEM, Mr. J. Bierlich for TG/DTA measurements and Dr. R. Müller (IPHT Jena) for high temperature VSM measurements.


  1. 1.
    M. Endo, A. Nakano, in Proceedings of the Eighth International Conference on Ferrites (ICF8), Kyoto, p. 1168, 2000Google Scholar
  2. 2.
    J. Smit, H.P.J. Wijn, Ferrites (Philips Technical Library, Eindhoven 1959)Google Scholar
  3. 3.
    P.B. Brown, Philips Res. Rep. 12, 491–548 (1957)Google Scholar
  4. 4.
    M. Sugimoto, Ferromagnetic Materials, vol. 3, ed. by E.P. Wohlfahrt (North-Holland Publishing, The Netherlands, 1982), pp. 393–439Google Scholar
  5. 5.
    J. Temuujin, M. Aoyama, M. Senna, T. Masuko, C. Ando, H. Kishi, J. Mater. Res. 20, 1939–1942 (2005)CrossRefADSGoogle Scholar
  6. 6.
    X.H. Wang, L. Li, Z. Gui, S. Shu, J. Zhou, Mater. Chem. Phys. 77, 248–253 (2002)CrossRefGoogle Scholar
  7. 7.
    D.W. Hahn, Y.H. Han, Mater. Chem. Phys. 95, 248–251 (2006)CrossRefGoogle Scholar
  8. 8.
    H. Zhang, L. Li, J. Zhou, Z. Yue, Z. Ma, Z. Gui, J. Eur. Ceram. Soc. 21, 149–153 (2001)CrossRefGoogle Scholar
  9. 9.
    S. Kracunovska, J. Töpfer, J. Magn. Magn. Mater. (2007 in press)Google Scholar
  10. 10.
    T. Tachibana, K. Ohta, T. Shimada, T. Nakagawa, T. Yamamoto, M. Katsura, in Proceedings of the Eighth International Conference on Ferrites, (ICF8), Kyoto, p. 888, 2000Google Scholar
  11. 11.
    T. Tachibana, T. Nakagawa, Y. Takada, K. Izumi, T. Yamamoto, T. Shimada, S. Kawano, J. Magn. Magn. Mater. 262, 248–257 (2003)CrossRefADSGoogle Scholar
  12. 12.
    O. Kimura, K. Shoji, M. Matsumoto, M. Sakakura, in Proceedings of the Ninth International Conference on Ferrites, (ICF9), San Francisco, p. 641, 2004Google Scholar
  13. 13.
    H. Zhang, L. Li, J. Zhou, Z. Yue, Z. Gui, J. Am. Ceram. Soc 84, 2889–2894 (2001)CrossRefGoogle Scholar
  14. 14.
    H. Hang, C.S. Hsi, T.C. Lee, C.H. Chang, J. Magn. Magn. Mater. 268, 186–193 (2004)CrossRefADSGoogle Scholar
  15. 15.
    R.D. Shannon, Acta Cryst. A32, 751 (1976)Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Department SciTecUniversity of Applied Sciences JenaJenaGermany

Personalised recommendations