Effect of W Substitution on Structural, Dielectric and Electrical Properties of BaTiO 3 Ferroelectric Ceramics
2009; Taylor & Francis; Volume: 381; Issue: 1 Linguagem: Inglês
10.1080/00150190902869780
ISSN1563-5112
AutoresSheela Devi, Prasun Ganguly, Sameer Jain, A.K. Jha,
Tópico(s)Acoustic Wave Resonator Technologies
ResumoBarium titanate is used as material for many important and widely used ceramic components and devices such as high permittivity ceramic capacitors, piezoelectric ceramic transducers and thermisters with positive temperature coefficient of resistivity (PTCR) [1 Jones, R. E., Mainar, P. D., Olowolafe, J. O., Campbell, J. O. and Mogab, C. J. 1992. Electrical properties of sol-gel processed barium titanate films. Appl. Phys. Lett., 60: 1022[Crossref], [Web of Science ®] , [Google Scholar], 2 Cheung, M. C., Chan, H. L. W. and Choy, C. L. 2001. Study of barium titanate ceramics prepared by various methods. Journal of Materials Science, 36: 381–387. [Crossref], [Web of Science ®] , [Google Scholar], 3 Hu, H. and Krupanidhi, S. B. 1993. Enchanced electrical properties of ferroelectric Pb (Zr0.5 Ti0.5)O3 thin films grown with low energy oxygen ion assistance. J. Appl. Phys., 74: 3373–3382. [Crossref] , [Google Scholar], 4 Nowotny, J. and Rekas, M. 1994. Defect structure, electrical properties and transport in barium titanate VII. Chemical diffusion in Nb-doped BaTiO3. Ceramics International., 20(4): 265–275. [Crossref] , [Google Scholar]]. Samples of compositions BaTi 1 − x W x O 3 ; x = 0.0, 0.15 were prepared by solid-state reaction technique using high purity oxides/carbonates. The samples were calcined at 1150°C for 2 hrs and sintered at 1200°C and 1300°C for 2 hrs. XRD diffroctgrams show that a single phase layered perovskite structure is formed in the samples. Lattice parameters and tetragonal strain (c/a) are observed to decrease in the substituted sample. Dielectric constant and dielectric loss have been measured as a function of temperature and frequency. The variations of dielectric constant (ϵ r ) with temperature at various frequencies show that the compounds undergo a diffuse type ferro—paraelectric phase transition. Curie temperature is observed to decrease from 120°C to 85°C in the tungsten substituted sample. The temperature dependence of dc conductivity of the compound have also been investigated.
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