Role of doping and CuO segregation in improving the giant permittivity of CaCu{sub 3}Ti{sub 4}O{sub 12}
- Dipartimento di Chimica Fisica 'M. Rolla' dell'Universita, Universita degli Studi di Pavia, viale Taramelli 16, IT 27100 Pavia (Italy)
- Dipartimento di Chimica Fisica 'M. Rolla' dell'Universita, Universita degli Studi di Pavia, viale Taramelli 16, IT 27100 Pavia (Italy) and CNR-IENI, Sezione di Pavia, viale Taramelli 16, 27100 Pavia (Italy)
- CNR-IENI, Sezione di Pavia, viale Taramelli 16, 27100 Pavia (Italy)
- INFM-Dipartimento di Fisica 'A. Volta' dell'Universita, via Bassi 6, 27100 Pavia (Italy)
The dopant role on the electric and dielectric properties of the perovskite-type CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) compound is evidenced. Impedance spectroscopy measurements show that the relevant permittivity value attributed to sintered CCTO is due to grain boundary (g.b.) effects. The g.b. permittivity value of the pure CCTO can be increased of 1-2 orders of magnitude by cation substitution on Ti site and/or segregation of CuO phase, while the bulk permittivity keeps values 90{epsilon}r180. Bulk and g.b. conductivity contributions are discussed: electrons are responsible for the charge transport and a mean bulk activation energy of 0.07eV is obtained at room temperature for all the examined samples. The g.b. activation energy ranges between 0.54 and 0.76eV. Defect models related to the transport properties are proposed, supported by electron paramagnetic resonance measurements.
- OSTI ID:
- 20658224
- Journal Information:
- Journal of Solid State Chemistry, Vol. 177, Issue 12; Other Information: DOI: 10.1016/j.jssc.2004.09.009; PII: S0022-4596(04)00501-8; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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