Sains Malaysiana 39(6)(2010): 1007–1013

 

Dependence of Pyroelectric Properties of La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y/2) Ceramic on Electric Field, Grain Refinement and Ti/Nb Crystallite Sizes

(Kebergantungan Sifat Piroelektrik Seramik La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y/2) Terhadap Medan Elektrik dan Saiz Hablur Ti/Nb)

 

Wee Chen Gan* & WanHaliza Abd. Majid

Solid State Research Laboratory, Physics Department, University of Malaya

50603 Kuala Lumpur, Malaysia

 

Received: 14 August 2009 / Accepted: 1 April 2010

 

ABSTRACT

 

The pyroelectric properties of La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y/2) (LSBNT) ceramic pellets using several Ti/Nb ratios sintered at 1250¡C for 5 h were investigated. The samples were subjected to several values of electric fields in order to obtain the optimum electric field strength. The pyroelectric coefficients, (p) were measured using the quasi-static method by applying several heating rates. The results show that the Ti/Nb ratios and the dc poling field, (Edc) influenced the measured pyroelectric coefficient of the LSBNT ceramic pellets. The mean grain size of the particles as obtained from scanning electron microscope (SEM) does not seem to give significant impact on the pyroelectric coefficient of the ceramic pellets. However, the X-Ray diffraction (XRD) results indicate that the crystallite sizes of Ti and Nb of these ceramic pellets after being treated with sintering process also influence the measured pyroelectric coefficients of the ceramic pellets.

 

Keywords: Ferroelectric ceramic; pyroelectric; spontaneous polarization

 

ABSTRAK

 

Sifat piroelektrik La0.03Sr0.255Ba0.7Nb2-yTiyO(6-y/2) (LSBNT) pelet seramik dengan nisbah Ti/Nb yang berlainan selepas dipanaskan pada suhu 1250¡C selama 5 jam telah dikaji. Sampel dikenakan medan elektrik yang berlainan supaya ia mencapai keadaan medan elektrik yang optimum. Pekali piroelektrik, (p) ditentukan dengan menggunakan kaedah kuasi-statik. Keputusan yang didapati menunjukkan nisbah Ti/Nb dan medan kutub arus terus, (Edc) mempengaruhi pekali piroelektrik seramik LSBNT yang dikaji. Saiz butiran seperti yang didapati daripada mikroskop imbiasan elektron (SEM) tidak menunjukkan sebarang pengaruh yang ketara terhadap pekalian piroelektrik seramik. Bagaimanapun, keputusan pembiasan sinar-X (XRD) yang diperolehi menunjukkan saiz hablur Ti dan Nb seramik yang telah dirawat dengan proses pemanasan menpengaruhi pekali piroelektrik seramik.

 

Kata kunci: Pengutuban spontan; piroelektrik; seramik feroelektrik

 

REFERENCES

 

Abd Majid W.H. 1994. Pyroelectric activity in cyclic and linear polysiloxane Langmuir blodgett films. Ph.D. Thesis, University of Sheffield.

Amorin, H., Portelles, J., Guerrero, F., Fundora, A., Martinez, E. & Siqueiros, J.M. 2000a. Formation of the La0.03Sr0.255Ba0.7Nb2−yTiyO(6−y)/2 ferroelectric system. Journal of Materials Science 35: 4607-4613.

Amorin, H., Portelles, J., Guerrero, F., Fundora, A. & Siqueiros, J. 1999. Formation properties of the La0.03Sr0.255Ba0.7Nb2−yTiyO(6−y)/2 ceramic system. Journal of Electroceramics 3(4): 371-375.

Amorin, H., Portelles, J., Guerrero, F., Perez, J. & Siqueiros, J.M. 2000b. Dielectric hysteresis and pyroelectricity in the La0.03Sr0.255Ba0.7Nb2−yTiyO(6−y)/2 ferroelectric ceramic system. Solid State Communications 113: 581-585.

Ares, J.R., Pascual, A., Ferrer, I.J. & Sanchez, C. 2005. Grain and crystallite size in polycrystalline pyrite thin films. Thin Solid Films 480-481: 477-481.

Calzada, M.L., Bretos, I., Jimenez, R., Ricote, J. & Mendiola, J. 2004. X-ray characterisation of chemical solution deposited PbTiO3 films with high Ca doping. Thin Solid Films 450: 211.

Chiang, Y.M., D.P. Birnie, III, & Kingery, W.D. 1997. Physical ceramics: Principles for Ceramic Science & Engineering. New York: John Wiley & Sons, Inc.

Harrison, J.S. & Ounaies, Z. 2001. Piezoelectric polymers. ICASE Report No. 2001-43: 1-26.

Jamieson, P.B., Abrahams, S.C. & Bernstein, J.L. 1968. Ferroelectric Tungsten Bronze Type Crystal Structures. I. Barium Strontium Niobate Ba0.27Sr0.75Nb2O5.78. J. Chem. Phys. 48(11): 5048.

Kingery, W.D., Bowen, H.K. & Uhlmann, D.R. 1976. Introduction to ceramics. New York: John Wiley & Sons, Inc.

Kouchachvili, L. & Ikura, M. 2007. Pyroelectric conversion—Effects of P(VDF–TrFE) preconditioning on power conversion. Journal of Electrostatics 65: 182-188.

Lang, S.B. 2005. Pyroelectricity: From ancient curiosity to modern imaging tool. Physics Today 31-36.

Liete, E., Bernardi, M.I.B., Longo, Varela, J.A. & Paskocimas, C.2004. Enhanced electrical property of nanostructured Sb-doped SnO2 thin film processed by soft chemical method. Thin Solid Films 449: 67.

Liu, S.T. & Bhalla, S. 1983. Some interesting properties of dislocation free and La-modified Sr0.5Ba0.5Nb2O6. Ferroelectrics 51: 47-51.

Maciolek, R.B. & Liu, S.T. 1975. Preparation and physical properties of lanthanum-modified Srl-xBaxNb2O6 ferroelectric crystals. Journal of Electronic Materials 4: 571-526.

Nagata, K., Yamamoto, Y., Igarashi, H. & Okazaki, K. 1981. Properties of the hot-pressed strontium barium niobate ceramics. Ferroelectrics 38: 853-856.

Okada, K., Nagashima, T., Kameshima, Y. & Yasumori, A. 2003. Effect of crystallite size ofboehmite on sinterability of alumina ceramics. Ceram. Int. 29: 533.

Perez, J., Amorin, H., Portelles, J., Guerrero, F., M’Peko, J.C. & Siqueiros, J.M. 2001. Electrical properties of the titanium modified SBN ceramic system. Journal of Electroceramics 6(2): 153-157.

Rittidech, A. & Khotsongkram, P. 2006. Effect of ball milling times on phase formation of Mg0.7Zn0.3Fe2O4. American Journal of Applied Sciences 3(3): 1760-1762.

Umakantham, K. Chandramouli, K. Nageswara Rao, G. & Bhanumathi, 1996. Bull. Mater. Sci. 19(2): 345.

Xu, G., Zhang, Y.W., Liao, C.S. & Yan, C.H. 2004. Grain size-dependent electrical conductivity in scandia-stabilized zirconia prepared by a mild urea-based hydrothermal method. Solid State Ionics 166: 391.

Xu, Y. 1991. Ferroelectric Materials and Their Applications Los Angeles, USA: Elsevier Science (North-Holland).

Solid State Research Laboratory

 

*Corresponding author; email: wcgan1981@yahoo.com.sg

 

 

 

previous