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Oxygen transport during formation and decomposition of AgNbO3 and AgTaO3

Published online by Cambridge University Press:  31 January 2011

Matjaz Valant*
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Anna-Karin Axelsson
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Bin Zou
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
Neil Alford
Affiliation:
London South Bank University, Centre for Physical Electronics and Materials, SE1 0AA London, United Kingdom
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

A thermogravimetric method was used to analyze intermediate processes involved in the formation and decomposition of AgNbO3and AgTaO3perovskites. Critical parameters that control the kinetics of the formation are associated with oxygen transport. The Nb2O5crystal structure has a capacity to trap molecular oxygen, which evolves during the decomposition of Ag2O that is present in a starting mixture. The formation of the perovskite phase involves a simultaneous reaction of three species: O2, Ag, and Nb2O5/Ta2O5. As the trapped molecular oxygen is in the immediate vicinity of the reaction site, the kinetics of the reaction is significantly accelerated. An absence of the molecular oxygen in the solid-state phase cannot be compensated for with an increase in a partial pressure of oxygen in the gas phase, that is, application of oxygen atmosphere.

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Articles
Copyright
Copyright © Materials Research Society2007

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References

REFERENCES

1Kania, A.: AgNb1−xTaxO3solid solutions—dielectric properties and phase transition. Phase Transitions 3, 131 1983Google Scholar
2Pawełczyk, M.: Phase transition in AgTaxNb1−xO3solid solutions. Phase Transitions 8, 273 1999CrossRefGoogle Scholar
3Valant, M., Suvorov, D., Hoffmann, C.Sommariva, H.: Ag(Nb,Ta)O3-based ceramics with suppressed temperature dependence of permittivity. J. Eur. Ceram. Soc. 21, 2647 2001CrossRefGoogle Scholar
4Saito, A., Uraki, S., Kakemoto, H., Tsurumi, T.Wada, S.: Growth of lithium doped silver niobate single crystals and their piezoelectric properties. Mater. Sci. Eng., B—Solid State Mater.Adv. Technol. 120, 166 2005CrossRefGoogle Scholar
5Sakabe, Y., Takeda, T., Ogiso, Y.Wada, N.: Ferroelectric properties of (Ag,Li)(Nb,Ta)O3ceramics. Jpn. J. Appl. Phys. 40, 5675 2001CrossRefGoogle Scholar
6Zimmermann, F., Menesklou, W.Ivers-Tiffee, E.: Investigation of Ag(Ta,Nb)O3as tunable microwave dielectric. J. Eur. Ceram. Soc. 24, 1811 2004CrossRefGoogle Scholar
7Koh, J.H., Khartsev, S.I.Grishin, A.: Ferroelectric silver niobate-tantalate thin films. Appl. Phys. Lett. 77, 4416 2000CrossRefGoogle Scholar
8Valant, M., Suvorov, D.Meden, A.: New high-permittivity AgNb1−xTaxO3microwave ceramics: Part I, crystal structures and phase-decomposition relations. J. Am. Ceram. Soc. 82, 81 1999CrossRefGoogle Scholar
9B. L’vov Kinetics and mechanism of thermal decomposition of silver oxide. Thermochim. Acta 333, 13 1999CrossRefGoogle Scholar
10Boronin, A.I., Koscheev, S.V., Kalinkina, O.V.Zhidomirov, G.M.: Oxygen states during thermal decomposition of Ag2O: XPS and UPS study. React. Kinet. Catal. Lett. 63, 291 1998CrossRefGoogle Scholar
11Epling, W.S., Hoflund, G.B.Salaita, G.N.: Surface study of the thermal decomposition of Ag2CO3. J. Phys. Chem. B 102, 2263 1998CrossRefGoogle Scholar
12Weaver, J.F.Hoflund, G.B.: Surface study of the thermal decomposition of Ag2O. Chem. Mater. 6, 1693 1994CrossRefGoogle Scholar
13Karakaya, I.Thompson, W.T.Phase Equilibria Diagrams, CD-Rom Version 3.0 (American Ceramic Society and National Institute of Standards and Technology, 2005), Diagram No. 10245BGoogle Scholar
14Boronin, A.I., Koschev, S.V., Murzakhmetov, K.T., Avdeev, V.I.Zhidomirov, G.M.: Associative oxygen species on the oxidized silver surface formed under O2microwave excitation. Appl. Surf. Sci. 165, 9 2000CrossRefGoogle Scholar
15Rosenfeld, D., Schmid, P.E., Szeles, S., Levy, F., Demarne, V.Grisel, A.: Electrical transport properties of thin-film metal-oxide-metal Nb2O5oxygen sensor Sens. Actuators B 37, 83 1996CrossRefGoogle Scholar
16Sheasby, J.S.Cox, B.: Oxygen diffusion in alpha-niobium pentoxide. J. Less-Common Met. 15(2), 129 1968CrossRefGoogle Scholar
17Massiani, Y., Crousier, J-P.Streiff, R.: Diffusion of oxygen in transition metal oxides. I. Development, improvement and performance of the isotopic exchange method by a solid-gas reaction. Bibliographical analysis of the oxygen diffusion in Nb2O5. J. Solid State Chem. 23, 415 1978CrossRefGoogle Scholar
18Craig, D.C.Stephenson, N.C.: The structure of the bronze Na13Nb35O94and the geometry of ferroelectric domains. J. Solid State Chem. 3, 89 1971CrossRefGoogle Scholar