Electrical conductivity of Ca{sub 1-x}Sr{sub x}Ti{sub 0.65}Fe{sub 0.35}O{sub 3-{delta}}, x = 0, 0.5 and 1, polycrystalline compounds in the 300-500 K range
- Center of Science and Technology of Materials, Energy and Nuclear Research Institute, Travessa R 400, Cidade Universitaria, S. Paulo, SP 05508-900 (Brazil)
Highlights: Black-Right-Pointing-Pointer Fe-doped Sr and Ca titanates were synthesized by chemical and solid state reaction. Black-Right-Pointing-Pointer SPM images show striking differences in samples prepared by the two routes. Black-Right-Pointing-Pointer Impedance spectroscopy measurements show different electrical behaviors. Black-Right-Pointing-Pointer Correlations between the two macroscopic observations are shown. -- Abstract: Bulk and grain boundary electrical conductivity of oxygen deficient Ca{sub x}Sr{sub 1-x}Ti{sub 0.65}Fe{sub 0.35}O{sub 3-{delta}}, x = 0, 0.5 and 1.0, polycrystalline specimens were evaluated by impedance spectroscopy measurements in the 5 Hz-13 MHz frequency range from 300 to 500 K. The ceramic powders were synthesized by solid state reaction and by a chemical route, the polymeric precursor technique. The X-ray diffraction of the samples at room temperature shows the following perovskite crystalline structures: cubic for x = 0 and orthorhombic for x = 0.5 and 1.0. The impedance plots are composed of two semicircles ascribed to grains (bulk) and interfaces (grain boundaries) contributions. The impedance data show that sintered pellets using powders prepared by solid state synthesis present higher intergranular and intragranular resistivity values than pellets prepared by the chemical route. Observations of scanning probe microscopy topographic images of the surfaces of the sintered pellets show evident differences between the grain morphology of the pellets prepared with powders synthesized by the two routes.
- OSTI ID:
- 22212513
- Journal Information:
- Materials Research Bulletin, Vol. 47, Issue 5; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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