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Ac conductivity and dielectric properties of CuFe1−xCrxO2 : Mg delafossite

Lalanne, Maëva and Demont, Philippe and Barnabé, Antoine Ac conductivity and dielectric properties of CuFe1−xCrxO2 : Mg delafossite. (2011) Journal of Physics D: Applied Physics, 44 (18). 185401(1)-185401(7). ISSN 0022-3727

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Official URL: http://dx.doi.org/10.1088/0022-3727/44/18/185401


The electrical and dielectric properties of CuFe(1−x)Cr(x)O(2) (0 ≤ x ≤ 1) powders, doped with 3% of Mg and prepared by solid-state reaction, were studied by broadband dielectric spectroscopy in the temperature range from −100 to 150 °C. The frequency-dependent electrical and dielectric data have been discussed in the framework of a power law conductivity and complex impedance and dielectric modulus. At room temperature, the ac conductivity behaviour is characteristic of the charge transport in CuFe1−xCrxO2 powders. The substitution of Fe3+ by Cr3+ results in an increase in dc conductivity and a decrease in the Cu+–Cu+ distance. Dc conductivity, characteristic onset frequency and Havriliak–Negami characteristics relaxation times are thermally activated above −40 °C for x = 0.835. The associated activation energies obtained from dc and ac conductivity and from impedance and modulus losses are similar and show that CuFe1−xCrxO2 delafossite powders satisfy the BNN relation. Dc and ac conductivities have the same transport mechanism, namely thermally activated nearest neighbour hopping and tunnelling hopping above and below −40 °C, respectively.

Item Type:Article
Additional Information:Thanks to IOP science editor. The orinal version is available at http://iopscience.iop.org/ The original PDF of the article can be found at IOP Publishing website: http://iopscience.iop.org/0022-3727/44/18/185401
Audience (journal):International peer-reviewed journal
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Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:16 May 2012 08:02

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