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X-ray diffraction data for the new ferroelectric tetragonal tungsten bronze phases, Ba2RETi2M3O15:M=Nb and RE=La, Pr, Nd, Sm, Gd, Dy, (Bi);M=Ta and RE=La, Nd

Published online by Cambridge University Press:  01 March 2012

Gabrielle C. Miles
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
Martin C. Stennett
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
David Pickthall
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
Caroline A. Kirk
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
Ian M. Reaney
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom
Anthony R. West
Affiliation:
Department of Engineering Materials, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, United Kingdom

Abstract

X-ray powder diffraction data are presented for nine new phases with the tetragonal tungsten bronze structure. By comparison with the structure of the M=Nb,RE=La analogue, these contain Ba in the large pentagonal sites with coordination number 15, a range of large rare-earth cations and Bi in the twelve coordinate sites, and the smaller cations, Ti and either Nb or Ta, in the octahedral framework sites. The a lattice parameter data of the tetragonal unit cell show an approximately linear variation with trivalent ion radius, apart from Dy, whose value appears to be anomalous; data for c show little variation with trivalent ion radius.

Type
New Diffraction Data
Copyright
Copyright © Cambridge University Press 2005

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References

Kirk, C. A., Stennett, M. C., Reaney, I. M., and West, A. R. (2002). “A New Relaxor Ferroelectric,” J. Mater. Chem. JMACEP 12, 2609.CrossRefGoogle Scholar
Chen, X. M. and Yang, J. S. (1999). “Dielectric Characteristics of Ceramics in BaO-Nd 2O3-TiO 2-Ta 2O5 System,” J. Eur. Ceram. Soc. JECSER 10.1016/S0955-2219(98)00166-6 19, 139.CrossRefGoogle Scholar
Chen, X. M., Liu, C. L., Yang, J. S., and Wu, Y. J. (1999). “Ba4Nd 2Ti4Ta 6O30 Dielectric Ceramics Modified by Bi Substitution for Nd,” J. Solid State Chem. JSSCBI 148, 438.CrossRefGoogle Scholar
Miles, G. C., Stennett, M. C., Pickthall, D., Kirk, C. A., Reaney, I. M., and West, A. R. (in preparation).Google Scholar
Jamieson, P. B., Abrahams, S. C., and Bernstein, J. L. (1969). “Ferroelectric Tungsten Bronze-Type Crystal Structures. Π. Barium Sodium Niobate Ba(4+x)Na(2−2x)Nb10O30,” J. Chem. Phys. JCPSA6 10.1063/1.1670903 50, 4352.Google Scholar
Shannon, R. D. (1976) “Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides, “Acta Crystallogr., Sect. A: Cryst. Phys., Diffr., Theor. Gen. Crystallogr. ACACBN 10.1107/S0567739476001551 32, 751.CrossRefGoogle Scholar