Complex Impedance Analyses of Ba_1-xLi_0.5xBi_0.5xTiO₃ Solid Solution PTCR Ceramics

Abstract:

Conditions for the formation of (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ (0 ≤ x ≤0.6) solid solutions with positive temperature coefficient of resistance (PTCR) effect were studied. Solid solutions were prepared by solid state reaction technique. Samples were sintered under reducing atmosphere N₂/H₂ in the temperature range 1200–1450 °C with subsequent oxidation in air. The phase composition was investigated by X-ray powder diffraction method. It was found that samples of (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ (0 ≤ x ≤0.6) solid solutions at room temperature exhibit perovskite structure. Unit cell parameters of unstable at the room temperature compound Li_0.5Bi_0.5TiO₃ were determined by extrapolation of concentration dependence of the unit cell parameters in the (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ system. It was shown that minimum value of resistivity ρ_min rises with increase in x value. Complex impedance method shown that ceramic grains of (1-x)BaTiO₃–xLi_0.5Bi_0.5TiO₃ materials consist of three areas with different electrical properties. Boundary and outerlayer region of grains make the main contribution to the PTCR effect in lithium-containing solid solutions. It was shown that magnitude of the potential barrier's decreases with increasing x.

• Periodical: Solid State Phenomena (Volume 230)
• Pages: 211-216
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.230.211
• Online since: June 2015
• Authors: Tatiana Plutenko, Oleg V'yunov*, Dmytro Plutenko, Anatolii Belous, Darko Makovec
• Keywords: Barium Titanate (BT), Complex Impedance, Perovskite, PTCR

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