Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-17T18:05:44.552Z Has data issue: false hasContentIssue false
  • English
  • Français

Electric State and Chemical Bonding of (Mg4−xMnx)Nb2O9 Microwave Dielectric Ceramics

Published online by Cambridge University Press:  03 March 2011

Akinori Kan ,
Hirotaka Ogawa  and
Atsushi Yokoi
Akinori Kan*
Affiliation:
Faculty of Science and Technology, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan
Hirotaka Ogawa
Affiliation:
Faculty of Science and Technology, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan
Atsushi Yokoi
Affiliation:
Faculty of Science and Technology, Meijo University, Tempaku-ku, Nagoya 468-8502, Japan
*
a) Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

Solid solutions of (Mg4−xMnx)Nb2O9 (MMN), which have a corundum-type structure, showed a single phase over the entire composition range, and lattice parameters of MMN linearly increased with increased composition x. From the calculation of cation–oxygen bonds in NbO6 and MO6 (M = Mg and Mn) octahedra, it was found that the covalency of the Nb–O bond was decreased by the Mn substitution for Mg; the molecular orbital calculation in (NbM12O45)−61 cluster models also revealed that the covalency of the Nb–O bond in the (NbMn12O45)−61 cluster model is smaller than that of the Nb–O bond in the (NbMg12O45)−61 cluster model. This result is attributed to the differences in the density of state, which arise from the overlap population of Mg-3d, Mn-3d, Nb-5s, and O-2p orbitals. The dielectric constant and Q⋅f values varied from 11 to 16 and from 210,000 to 50,000 GHz, respectively. Thus, it is considered that these variations in the microwave dielectric properties may be related to the covalency of the cation–oxygen bonds.

Keywords

CeramicDielectricX-ray diffraction (XRD)
Type
Articles
Information
Journal of Materials Research , Volume 20 , Issue 9 , September 2005 , pp. 2456 - 2461
Copyright
Copyright © Materials Research Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Penn, S.J., Alford, N.McN., Templeton, A., Wang, X., Xu, M., Reece, M. and Schrapel, K. Effect of porosity and grain size on the microwave dielectric properties of sintered alumina. J. Am. Ceram. Soc., 80(7), 1885 (1997).CrossRefGoogle Scholar
2Kumada, N., Taki, K. and Kinomura, N.: Single-crystal structure of magnesium niobium oxide: Mg4Nb2O9. Mater. Res. Bull. 35, 1017 (2000).CrossRefGoogle Scholar
3Ogawa, H., Kan, A., Ishihara, S. and Higashida, Y.: Crystal structure of corundum type Mg4(Nb2−x Tax)O9 microwave dielectric ceramics with low dielectric loss. J. Eur. Ceram. Soc. 23(14), 2485 2003.CrossRefGoogle Scholar
4Kan, A., Ogawa, H. and Ohsato, H.: Relationship between bond strength and microwave dielectric properties of corundumtype (Mg4−xCox)Nb2O9 and Mg4(Nb2−yTay)O9 solid solutions. J. Ceram. Soc. Jpn. 112(5), 1622 (2004).Google Scholar
5Izumi, F. and Ikeda, T.: A Rietveld-analysis program RIETAN-98 and its applications to zeolites. Mater. Sci. Forum 321–324, 198 (2000).CrossRefGoogle Scholar
6Brown, I.D. and Shannon, R.D.: Empirical bond-strength—bond-length curves for oxides. Acta Crystallogr. A 29, 266 (1973).CrossRefGoogle Scholar
7Brown, I.D.: Empirical parameters for calculating cation–oxygen bond valences. Acta Crystallogr. B32, 1957 (1976).CrossRefGoogle Scholar
8Adachi, H., Tsukada, M. and Satoko, C.: Discrete variational Xα cluster calculations. I. Application to metal clusters. J. Phys. Soc. Jpn. 45, 875 (1978).CrossRefGoogle Scholar
9Tsukada, M., Satoko, C. and Adachi, H.: Theory of the surface electronic structure and defect states of rutile by the DV-Xα cluster calculation. J. Phys. Soc. Jpn. 47, 1610 (1979).CrossRefGoogle Scholar
10Hakki, B.W. and Coleman, P.D. A dielectric resonator method of measuring inductive capacities in the millimeter range. IRE Trans. Microwave Theory Tech. MTT-8,402 (1960).CrossRefGoogle Scholar
11Kobayashi, Y. and Katoh, M.: Microwave measurement of dielectric properties of low-loss materials by dielectric resonator method. IEEE Trans. Microwave Theory Tech. MMT-33, 586 (1985).CrossRefGoogle Scholar
12Shannon, R.D.: Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr. A 32, 751 (1976).CrossRefGoogle Scholar
13Lee, H.J., Hong, K.S., Kim, S.J. and Kim, I.T.: Dielectric properties of M Nb2O6 compounds (where M = Ca, Mn, Co, Ni or Zn). Mater. Res. Bull. 32(7), 847 (1997).CrossRefGoogle Scholar