Electrical properties of lanthanum doped barium titanate ceramics

Journal Article · Sat Oct 15 00:00:00 EDT 2011 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2011.07.013· OSTI ID:22066339

Bobic, J D ^[1]; Ramoska, T; Banys, J ^[2]; Stojanovic, B D ^[1]

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1. Institute for Multidisciplinary Research, Belgrade University, Kneza Viseslava 1, Belgrade (Serbia)
2. Faculty of Physics, Vilnius University, Sauletekio al. 9, Vilnius (Lithuania)

Pure and lanthanum doped barium titanate (BT) ceramics were prepared by sintering pellets at 1300 deg. C for 8 h, obtained from nanopowders synthesized by the polymeric precursor method. XRD results showed formation of a tetragonal structure. The presence of dopants changed the tetragonal structure to pseudo-cubic. The polygonal grain size was reduced up to 300 nm with addition of lanthanum as a donor dopant. Determined dielectric properties revealed that lanthanum modified BT ceramics possessed a diffused ferroelectric character in comparison with pure BT that is a classical ferroelectric material. In doped BT phase transition temperatures were shifted to lower temperatures and dielectric constant values were much higher than in pure BT. A modified Currie Weiss law was used to explore the connection between the doping level and degree of diffuseness of phase transitions. Impedance spectroscopy measurements were carried out at different temperatures in order to investigate electrical resistivity of materials and appearance of a PTCR effect. - Highlights: {yields} Pure and lanthanum doped BaTiO{sub 3} were prepared by polymeric precursors method. {yields} Change of structure from tetragonal to pseudo-cubic. {yields} Lanthanum as a donor dopant influenced on change of ferro-para phase transition. {yields} The diffuseness factor indicated the formation of diffuse ferroelectric material. {yields} Lanthanum affected on PTCR effect appearance in BT ceramics.

• OSTI ID: 22066339
• Journal Information: Materials Characterization, Vol. 62, Issue 10; Other Information: Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
77 NANOSCIENCE AND NANOTECHNOLOGY
CERAMICS
COMPARATIVE EVALUATIONS
DOPED MATERIALS
ELECTRIC CONDUCTIVITY
FERROELECTRIC MATERIALS
GRAIN SIZE
IMPEDANCE
LANTHANUM
NANOSTRUCTURES
PERMITTIVITY
PHASE TRANSFORMATIONS
POWDERS
SINTERING
SPECTROSCOPY
SYNTHESIS
TETRAGONAL LATTICES
TITANATES
TRANSITION TEMPERATURE
X-RAY DIFFRACTION