Please use this identifier to cite or link to this item: http://localhost:8080/xmlui/handle/123456789/2611
Title: Pyrochlore Type Semiconducting Ceramic Oxides in Ca–Ce–Ti–M–O System (M = Nb or Ta)—Structure, Microstructure and Electrical Properties
Authors: Deepa, M
Prabhakar Rao, P
Radhakrishnan, A N
Sibi, K S
Peter Koshy
Keywords: A. Oxides
A. Semiconductors
C. X-ray diffraction
C. Raman spectroscopy
C. Electron microscopy
D. Electrical properties
Issue Date: 1-Jul-2009
Publisher: Elsevier
Citation: Materials Research Bulletin, 44(7):1481-1488
Abstract: A new series of pyrochlore type ceramic semiconducting oxides in Ca–Ce–Ti–M–O (M = Nb or Ta) system has been synthesized by the conventional ceramic route. The electrical conductivity measurements show that these oxides exhibit semiconducting behavior and the conductivity increases with the Ce content in the compound. Activation energy of the current carriers is in the range of 0.5–1.6 eV. The electrical conductivity in these oxides is due to the presence of Ce3+, which remains in the reduced state without being oxidized to Ce4+ by structural stabilization. The photoluminescence and X-ray photoelectron spectroscopy analysis corroborate the presence of Ce in the 3+ state. Impedance spectral analysis is carried out to evaluate the transport properties and indicates that the conduction in these compounds is mainly due to electronic contribution. The X-ray powder diffraction and Raman spectroscopy analysis establishes that these oxides belong to a cubic pyrochlore type structure.
URI: http://hdl.handle.net/123456789/2611
Appears in Collections:2009

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