Oxygen vacancy related defect dipoles in CaCu3Ti4O12: Detected by electron paramagnetic resonance spectroscopy. Issue 7 (July 2015)

• Record Type: Journal Article
• Authors: Luo, X.J.; Liu, Y.S.; Yang, C.P.; Chen, S.S.; Tang, S.L.; Bärner, K.
• Is Part Of: Journal of the European Ceramic Society. Volume 35:Issue 7(2015:Jul.)
• Page Start: 2073
• Page End: 2081
• Publication Date: 2015-07
• Subjects: EPR -- Defect dipole -- Oxygen vacancy; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2015.01.024
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Oxygen vacancy associate defects were studied by electron paramagnetic resonance (EPR) for the perovskite oxide CaCu3 Ti4 O12 (CCTO), which have a colossal dielectric constant. It is found that the EPR line width of the Cu 2+ –host signal of CCTO correlates with its permittivity. A new signal was found in the second differential of the Cu 2+ –host signal, which we think is associated with a specific copper–oxygen vacancy defect. This signal shows a negative g factor shift with temperature, suggesting a contribution to the conduction. Assuming solid state reactions between the various defects and using the mass action law, we offer a more specific relation between permittivity, the content of oxygen vacancy and the new signal, which might be useful for an indirect but fast oxygen vacancy content determination.