Single-phase polycrystalline samples of lead titanate with perovskite structure have been synthesized using solid-state reaction technique. The processing parameters have been optimized to obtain phase pure, dense, crack-free, and homogeneous samples. The sintering behavior of PT-powders has been investigated using X-ray diffraction patterns. The X-ray powder diffraction data have been analyzed to confirm the phase formation and phase purity, to obtain unit cell parameters and unit cell volume. The porosity of the samples has been obtained through X-ray density and bulk density. The average particle sizes of the phase pure samples were obtained from the X-ray peak width using Scherrer’s formula. The influence of sintering temperature and time on the microstructure of samples has also been studied by carrying out SEM investigations. The notable feature of this microstructure study shows that the samples sintered at 900°C for 12 hours possess a fairly uniform grain distribution. The electrical behavior (complex impedance Z*, complex permittivity ε*, etc.) of the samples sintered at 900°C for 12 hours has been studied by complex impedance spectroscopy. The temperature variation of real permittivity gives evidence of the ferroelectric phase transition as well as of the relaxation behavior. 1. Introduction Crystals of the perovskitefamily, such as PbTiO3, BaTiO3, SrTiO3 and, have been of constant interest because some ofthese materials show ferroelectric behavior and undergo structural phase transitions [1]. PbTiO3 has been considered to be one of the most important members of this family. It has a high Curie temperature, high pyroelectric coefficient, low dielectric constant, and high spontaneous polarization [2]. Lead titanate (PbTiO3, PT) is a ferroelectric ceramic that has not been proved to be a technologically important material by itself but is a significant component material in electronics such as capacitors, ultrasonic transducers, thermistors, and optoelectronics [3–7]. It is also a promising material for pyroelectric infrared detector applications because of its large pyroelectric coefficient and relatively low permittivity [8, 9]. PbTiO3 (PT) has also been extensively used in a range of piezoelectric applications, as well as being the end member of technologically significant ferroelectric perovskite series such as PbZr(x)Ti(1？x)O3 (PZT), Pb(x)Ca(1？x)TiO3, Pb(Zn1/3Nb2/3)O3-(x) PbTiO3 (PZN-PT), and Pb (Mg1/3Nb2/3) O3-(x) PbTiO3 (PMN-PT) and so forth. At ambient temperature, the material has a strong anisotropy which develops during cooling
References
[1]
F. Jona and G. Shirane, Ferroelectric Crystals, MacMillan, New York, NY, USA, 1962.
[2]
R. Migoni, H. Bilz, and D. Bauerle, “Origin of raman scattering and ferroelectricity in oxidic perovskites,” Physical Review Letters, vol. 37, no. 17, pp. 1155–1158, 1976.
[3]
L. E. Cross, “Dielectric, piezoelectric and ferroelectric components,” The Bulletin of the American Ceramic Society, vol. 63, pp. 586–590, 1984.
[4]
K. Sasazawa, K. Oshima, and N. Yamaoka, “Surface potential decay and residual voltage measurements in highly elongated polyethylene,” Japanese Journal of Applied Physics, vol. 26, pp. L65–L67, 1987.
[5]
T. R. Shrout and A. Halliyal, “Preparation of lead-based ferroelectric relaxors for capacitors,” American Ceramic Society Bulletin, vol. 66, pp. 704–711, 1987.
[6]
D. Damjanovic, T. R. Gururaja, and L. E. Cross, “Anisotropy in piezoelectric properties of modified lead titanate ceramics,” American Ceramic Society Bulletin, vol. 66, no. 4, pp. 699–703, 1987.
[7]
M. Kuwabara, “Lead titanate ceramics with positive temperature coefficients of resistivity,” Journal of the American Ceramic Society, vol. 73, no. 5, pp. 1438–1439, 1990.
[8]
Y. Chan, H. L. W. Chan, and C. L. Choy, “Nanocrystalline lead titanate and lead titanate/vinylidene fluoride-trifluoroethylene 0-3 nanocomposites,” Journal of the American Ceramic Society, vol. 81, no. 5, p. 1231, 1998.
[9]
R. Y. Ting, “Evaluation of new piezoelectric composite materials for hydrophone applications,” Ferroelectrics, vol. 67, no. 1, pp. 143–157, 1978.
[10]
G. Shirane and S. Hoshino, “On the phase transition in lead titanate,” Journal of the Physical Society of Japan, vol. 6, pp. 265–270, 1951.
[11]
Y. XU, Ferroelectric Materials and Their Applications, North Holland, Amsterdam, The Netherlands, 1991.
[12]
L. B. Archer, C. D. Chandler, R. Kingsborough, and M. J. Hampden-Smith, “Synthesis and characterization of perovskite-phase mixed-metal oxides: lead titanate,” Journal of Materials Chemistry, vol. 5, no. 1, pp. 151–158, 1995.
[13]
T. W. Dekleva, J. M. Hayes, L. E. Cross, and G. L. Geoffroy, “Sol—gel processing of lead titanate in 2-methoxyethanol: investigations into the nature of the prehydrolyzed solutions,” Journal of the American Ceramic Society, vol. 71, no. 5, pp. C280–C282, 1988.
[14]
J. Moon, T. Li, C. A. Randall, and J. H. Adair, “Low temperature synthesis of lead titanate by a hydrothermal method,” Journal of Materials Research, vol. 12, no. 1, pp. 189–197, 1997.
[15]
J. D. Tsay and T. T. Fang, “Effects of temperature and atmosphere on the formation mechanism of barium titanate using the citrate process,” Journal of the American Ceramic Society, vol. 79, no. 6, pp. 1693–1696, 1996.
[16]
J. S. Forrester, J. S. Zobec, D. Phelan, and E. H. Kisi, “Synthesis of PbTiO3 ceramics using mechanical alloying and solid state sintering,” Journal of Solid State Chemistry, vol. 177, no. 10, pp. 3553–3559, 2004.
[17]
L. S. Hong and C. C. Wei, “Effect of oxygen pressure upon composition variation during chemical vapor deposition growth of lead titanate films from tetraethyl lead and titanium tetraisopropoxide,” Materials Letters, vol. 46, no. 2-3, pp. 149–153, 2000.
[18]
S. Kim, M. C. Jun, and S. C. Hwang, “Preparation of undoped lead titanate ceramics via sol-gel processing,” Journal of the American Ceramic Society, vol. 82, no. 2, pp. 289–296, 1999.
[19]
G. M. Algueró, G. Drazic, M. Kosec, M. L. Calzada, and L. Pardo, “Evolución microestructural durante la transformación de la estructura pirocloro en perovskita en láminas de (Pb,La)TiO3,” Boletín de la Sociedad Espa？ola de Cerámica y Vidrio, vol. 41, no. 1, pp. 98–101, 1999.
[20]
S. Ananta and N. W. Thomas, “Fabrication of PMN and PFN ceramics by a two-stage sintering technique,” Journal of the European Ceramic Society, vol. 19, no. 16, pp. 2917–2930, 1999.
[21]
K. Katayama, M. Abe, T. Akiba, and H. Yanagida, “Sintering and dielectric properties of single-phase Pb(Mg 1/3Nb 2/3)O3-PbTiO3,” Journal of the European Ceramic Society, vol. 5, no. 3, pp. 183–191, 1989.
[22]
J. Xue, D. Wan, and J. Wang, “Mechanochemical synthesis of nanosized lead titanate powders from mixed oxides,” Materials Letters, vol. 39, no. 6, pp. 364–369, 1999.
[23]
B. D. Cullity, Elements of X-Ray Diffraction, Addison-Wesley, Boston, Mass, USA, 2nd edition, 1978.
[24]
G. H. Haertling, “Ferroelectric ceramics: history and technology,” Journal of the American Ceramic Society, vol. 82, no. 4, pp. 797–818, 1999.
[25]
L. E. Cross, “Ferroelectric materials for electromechanical transducer applications,” Materials Chemistry and Physics, vol. 43, no. 2, pp. 108–115, 1996.
[26]
R. Yimnirun, S. Ananta, and P. Laoratanakul, “Effects of Pb(Mg1/3Nb2/3)O3 mixed-oxide modification on dielectric properties of Pb(Zr0.52Ti0.48)O3 ceramics,” Materials Science and Engineering B, vol. 112, no. 1, pp. 79–86, 2004.
[27]
R. D. Shannon and C. T. Prewitt, “Effective ionic radii in oxides and fluorides,” Acta Crystallographica, vol. 25, pp. 925–946, 1969.
[28]
A. Halliyal, U. Kumar, R. E. Newnham, and L. E. Cross, “Stabilization of the Perovskite Phase and Dielectric Properties of Ceramics in the Pb(Zn1/3Nb2/3)O3-BaTiO3 System,” American Ceramic Society Bulletin, vol. 66, no. 4, pp. 671–676, 1987.
[29]
N. Vittayakorn, G. Rujijanagul, X. Tan, M. A. Marquardt, and D. P. Cann, “The morphotropic phase boundary and dielectric properties of the xPb(Zr1/2Ti1/2)O3-(1？x)Pb(Ni1/3Nb2/3)O3 perovskite solid solution,” Journal of Applied Physics, vol. 96, no. 9, p. 5103, 2004.
[30]
S. M. Pilgrim, A. E. Sutherland, and S. R. Winzer, “Diffuseness as a useful parameter for relaxor ceramics,” Journal of the American Ceramic Society, vol. 73, no. 10, pp. 3122–3135, 1990.
