Effect of Ba2+ in BNT ceramics on dielectric and conductivity properties


The polycrystalline (Na0.5Bi0.5)1-xBaxTiO3 (x = 0.026, 0.055 & 0.065) (BNBT) ceramics have been synthesized by conventional solid state sinter-ing technique. The tolerance (t) factor of the BNBT composition have been estimated and found to be 0.988, 0.990 and 0.991 for x = 0.026, 0.055 and 0.065 respectively, revealing system is stable perovskite type structure. The com-pound has a rhombohedral-tetragonal Morphtropic Phase Boun- dary (MPB) at x = 0.065. XRD re-sults indicated the crystalline structure of the investigated materials are of single phase with rhombohedral structure and the average parti-cle size of the calcined powder is found to lie between 45 nm - 60 nm. The effect of Ba2+ on dielectric and conductivity properties in Bis-muth Sodium Titanate (BNT) has been studied. The variation of dielectric constant with fre-quency (45 Hz-5 MHz) and temperature (35℃-590℃) has been performed. The value of Tm and Td are found to decrease with increase of concentration of Barium in BNT. The value of tan in the studied materials is found to be the order of 10-2 indicating low loss materials. The evaluated Curie constant in the composi-tion is found to be the order of 105 revealing the materials belong to oxygen octahedra ferro-electrics. The theoretical dielectric data of the studied composition have been fitted by us- ing Jonscher’s dielectric dispersion relation: . The pre-factor a(T), which indicates the strength of the po-larizability showed a maximum at transition temperature (Tm). The exponent n(T) which gives a large extent of interaction between the charge carriers and polarization is found to be minimum in the vicinity of Tm. The A.C. and d.c conductivity activation energies have been eva- luated; the difference in activation energies could be due to the grain boundary effect. The activation enthalpy energies, have been esti-mated and found to be Hm = 0.37 eV, 0.26 eV and 0.25 eV for BNBT-26, BNBT-55 and BNBT-65 re-spectively.

Share and Cite:

Rao, K. , Rajulu, K. , Tilak, B. and Swathi, A. (2010) Effect of Ba2+ in BNT ceramics on dielectric and conductivity properties. Natural Science, 2, 357-367. doi: 10.4236/ns.2010.24043.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Gomah-Pettry, J.R., Marchet, P., Salak, A., Ferriera, V.M. and Mercurio, J.P. (2004) Electrical properties of Na0.5Bi0.5TiO3- SrTiO3 ceramics. Integrated Ferroelectrics, 61(1), 159-162.
[2] Nageta, H., Yoshida, M., Makiuchi, Y. and Takenaka, T. (2003) Large piezoelectric constant and high curie tem-perature of lead-free piezoelectric ceramic ternary system based on bismuth sodium titanate-bismuth potassium ti-tanate-barium titanate near the morphotropic phase boun- dary. Japanese Journal of Applied Physics, 42, 7401-7403.
[3] Takenaka, T. and Nagata, H. (2005) Current status and prospects of lead-free piezoelectric ceramics. Journal of the European Ceramic Society, 25(12), 2693-2700.
[4] Herabut, A. and Safari, A. (1997) Processing and elec-tromechanical properties of (Bi0.5Na0.5)(1-1.5x)LaxTiO3 ceramics. Journal of the American Ceramic Society, 80(11), 2954-2958.
[5] Ishii, H., Nagata, H. and Takenaka, T. (2001) Mor-photropic phase boundary and electrical properties of bi-sumuth sodium titanate-potassium niobate solid-solution ceramics. Japanese Journal of Applied Physics, 40(9B), 5660-5663.
[6] Peng, C., Li, J.F. and Gong, W. (2005) Preparation and properties of (Bi1/2Na1/2)TiO3-Ba(Ti,Zr)O3 lead-free pie-zoelectric ceramics. Materials Letters, 59(12), 1576-1580.
[7] Chu, B.J., Chen, D.-R., Li. G.-R. and Yin, Q.-R. (2002) Electrical properties of Na1/2Bi1/2TiO3-BaTiO3 ceramics. Journal of the European Ceramic Society, 22(13), 2115- 2121.
[8] West, D.L. and Payne, D.A. (2003) Preparation of 0.95Bi1/2Na1/2TiO3•0.05BaTiO3 ceramics by an aqueous citrate-gel route. Journal of the American Ceramic Soci-ety, 86(1), 192-194.
[9] Kimura, T., Takahashi, T., Tani, T. and Saito, Y. (2004) Preparation of crystallographically textured Bi0.5Na0.5TiO3– BaTiO3 ceramics by reactive-templated grain growth method. Ceramics International, 30(7), 1161-1167.
[10] Xu, Q., Chen, S.T., Chen, W., Wu, S.J., Zhou, J., Sun, H.J. and Li, Y.M. (2005) Synthesis and piezoelectric and fer-roelectric properties of (Na0.5Bi0.5)(1-x)BaxTiO3 ceramics. Materials Chemistry and Physics, 90(1), 111-115.
[11] Gao, L., Huang, Y., Hu, Y. and Du, H. (2007) Dielectric and ferroelectric properties of (1-x)BaTiO3-xBi0.5Na0.5TiO3 ceramics. Ceramic International, 33(6), 1041-1046.
[12] Qu, Y., Shan, D. and Song, J. (2005) Effect of A-site substitution on crystal component and dielectric proper-ties in Bi0.5Na0.5TiO3 ceramics. Materials Science and Engineering B, 121(1-2), 148-151.
[13] Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallographica Section A, 32, 751-767.
[14] Muller, O. and Roy, R. (1974) The major ternary struc-tural families. Springer, New York, 221.
[15] Bhalla, A.S., Guo, R. and Roy, R. (2000) The perovskite structure—a review of its role in ceramic science and technology. Materials Research Innovations, 4(1), 3-26.
[16] Eitel, R.E., Randall, C.A., Shrout, T.R. and Rehrig, P.W. (2001) New high temperature morphotropic phase boun-dary piezoelectrics based on Bi(Me)O3-PbTiO3 ce- ram-ics. Japanese Journal of Applied Physics, 40(10), 5999-6002.
[17] Reaney, I.M., Colla, E.L. and Setter, N. (1994) Dielectric and structural characteristics of Ba-based and Sr-based complex perovskites as a function of tolerance factor. Japanese Journal of Applied Physics, 33(7A), 3984-3990.
[18] Suchomel, M.R. and Davies, P.K. (2004) Predicting the position of the morphotropic boundary in new high tem- perature PbTiO3-Bi(B'B")O3 based dielectric ceramics. Journal of Applied Physics, 96(8), 4405-4410.
[19] Isupov, V.A. (2005), Ferroelectric Na0.5Bi0.5TiO3 and K0.5Bi0.5TiO3 perovskites and their solid solutions. Ferro- electrics, 315(1), 123-147.
[20] Park, S.E. and Chung, S.J. (1994), Phase transition of ferroelectric (Na1/2Bi1/2)TiO3 on applications of ferro-electrics. Proceedings of the 9th IEEE International Sym-posium, ISAF’94, 265-268.
[21] Liu, Y.F., Lv, Y.N., Xu, M., Shi, S.Z., Xu, H.Q. and Yang, X.D. (2007) Structure and electric properties of (1-x)(Bi1/2Na1/2) TiO3-xBaTiO3 systems. Journal of Wuhan University of Technology - Materials Science Edition, 22(2), 315-319.
[22] Mahboob, S., Prasad, G. and Kumar, G.S. (2007) Im-pedance spectroscopy and conductivity studies on B site modified (Na0.5Bi0.5)(Nd-xTi(1-2x)Nbx)O-3 ceramics. Journal of Material Science, 42, 10275-10283.
[23] Takenaka, T. (1999) Piezoelectric properties of some lead-free ferroelectric ceramics. Ferroelectrics, 230, 87- 98.
[24] Liu, Y.F., et al. (2007) Journal of Wuhan University of Technology - Materials Science Edition.
[25] Takenaka, T. (1989) Piezoelectric properties of some lead-free ferroelectric ceramics. Ferroelectrics, 230, 389.
[26] Yoshii, K., Nagata, H. and Takenaka, T. (2006) Electri- cal properties and depolarization temperature of (Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3 lead-free piezoelectric ceramics. Japanese Journal of Applied Physics, 45, 4493.
[27] Takenaka, T., Okuda, T. and Takegahara, K. (1997) Lead-free piezoelectric ceramics based on (Bi1/2Na1/2) TiO3-NaNbO3. Ferroelectrics, 196, 175.
[28] Li, H.D., Feng, C.D. and Yao, W.L. (2005) Some effects of different additives on dielectric and piezoelectric properties of (Bi0.5Na0.5)TiO3-BaTiO3 morphotropic phase boundary composition. Materials Letters, 58, 1194- 1198.
[29] Nagata, H. and Takenaka, T. (2001) Additive effects on electrical properties of (Bi1/2Na1/2)TiO3 ferroelectric ce-ramics. Journal of European Ceramic Society, 21, 1299.
[30] Wei, Z., Heping, Z. and Yongke, Y., et al. (2007) Dielec-tric and piezoelectric properties of Y2O3 doped (Bi0.5Na0.5)0.94Ba0.06TiO3 lead-free piezoelectric ceram-ics. Key Engineering Materials, 105, 336-338.
[31] Lin, D., Xiao, D., Zhu, J. and Yu, P. (2006) Piezoelectric and ferroelectric properties of [Bi0.5Na1-x-yKxLiy0.5]TiO3 lead-free piezoelectric ceramics. Applied Physics Letters, 88.
[32] Tu, C.S., Siny, I.G. and Schimidt, V.H. (1994) Dielectric, NMR and X-Ray diffraction study of Cs1-x(NH4)xH2PO4. Physical Review B, 49, 11550.
[33] Chowdury, P.R. and Deshpande, S.B. (1984) Indian Journal of Pure & Applied Physics, 22, 708.
[34] Jonscher, A.K. and Dube, D.C. (1978) Low frequency dispersion in tri-glycyne sulphate. Ferroelectrics, 17, 533-536.
[35] Jonscher, A.K. (1989) Interpretation of non-ideal dielec-tric plots. Journal of Material Science, 24, 372.
[36] Garcia-Martin, S., Veiga, M.L., Pico, C., Santamaria, J., Gonzalez-Diaz, G. and Sanchez-Quesada, F. (1990) Di-electric response and ionic conductivity of Cs(NbTe)O6. Materials Research Bulletin, 25, 1393.
[37] Jonscher, A.K., Deori, K.L., Reau, J.M. and Moali, J. (1979) The dielectric response of KxAlxTi8-xO16 and KxMgx/2Ti8-x/2O16. Journal of Materials Science, 14, 1308- 1320.
[38] Garcia-Martin, S., Veiga, M.L., Pico, C., Santamaria, J., Gonzalez-Diaz, G. and Sanchez-Quesada, F. (1990) Barrier effects on ionic conductivity and dielectric re-sponse of Ti(NbTe)O6. Solid State Ionics, 44, 131.
[39] Varez, A., Alario-Franco, M.A., Santamaria, J., Gon-zalez-Diaz, G. and Sanchez-Quesada, F. (1990) Ionic conductivity of lithium inserted Ba2YCu3O7-y. Solid State Communications, 76(7), 917-920.
[40] Kumar, A., Singh, B.P., Choudary, R.N.P. and Thakur, A.K. (2005) A.C. impedance analysis of the effect of dopant concentration on electrical properties of calcium modified BaSnO3. Journal of Alloys and Compounds, 394(1-2), 292-302.
[41] Scott, B.A., Geiss, E.A., Olson, B.L., Burns, G., Smith, A.W. and O’Kane, D.F. (1970) The tungsten bronze field in the system K2O|Li2O|Nb2O5. Materials Research Bul-letin, 5(1), 47-56.
[42] Kroger, F.A. and Vink, H.J. (1956) Relations between the concentrations of imperfections in crystalline solids. Solid State Physics, 3, 307.
[43] Jonscherm A.K. (1983) Dielectric relaxation in solids. Chelesa Dielectric Press, London.
[44] Henn, F.E.G., Giuntini, J.C., Zanchetta, J.V., Granier, W. and Taha, A. (1990) Frequency dependent protonic con-duction in N2H5Sn3F7 glass and RbHSeO4 single crystal. Solid State Ionics, 42(1-2), 29-36.
[45] Giuntini, J.C., Deroide, B., Belougne, P. and Zanchetta, J.V. (1987) Numerical approach of the correlated barrier hopping model. Solid State Communications, 62, 739.
[46] Bensimon, Y., Giuntini, J.C., Belougne, P., Deroide, B. and Zanchetta, J.V. (1988) Solid State Communications, 68,189.
[47] Venkataraman, B.H. and Varma, K.B.R. (2004) Fre-quency-dependent dielectric characteristics of ferroe- lectric SrBi2Nb2O9 ceramics. Solid State Ionics, 167, 197-202.
[48] Krthik, C. and Varma, K.B.R. (2006) Dielectric and AC conductivity behavior of BaBi2Nb209 ceramics. Journal of Physics and Chemistry of Solids, 67(12), 2437-2441.
[49] Almond, D.P. and West, A.R. (1983) Mobile ion con-centrations in solid electrolytes from an analysis of a.c. conductivity. Solid State Ionics, 22, 277.
[50] Hill, R.M. and Jonscher, A.K. (1979) Journal of Non- Crystalline Solids, 32, 53.
[51] Almond, D.P., West, A.R. and Grant, R.J. (1982) Tem-perature dependence of the a.c. conductivity of Naβ- alumina. Solid State Communications, 44(8), 1277-1280.
[52] Sundarkannan, S., Kakimoto, K. and Ohsato, H. (2003) Journal of Applied Physics, 9, 5182.
[53] Lu, Z., Bonnet, J.P., Ravez, J. and Hagenmullar, P. (1992) Correlation between low frequency dielectric dispersion (LFDD) and impedance relaxation in ferroelectric ce-ramic Pb2KNb4TaO15. Solid State Ionics, 57(3-4), 235- 244.
[54] Thakur, O.P. and Prakash, C. (2003) Dielectric properties of samarium substituted barium strontium titanate. Phase Transformation, 76(6), 567-574.

Copyright © 2024 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.