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Polaron relaxation and variable-range-hopping conductivity in the giant-dielectric-constant material CaCu3Ti4O12

2004; American Physical Society; Volume: 70; Issue: 17 Linguagem: Inglês

10.1103/physrevb.70.174306

1550-235X

Lei Zhang, Zhongjia Tang,

Multiferroics and related materials

Transport and dielectric measurements have been performed in $\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$ ceramics. The bulk ac conductivity shows a power-law behavior at different temperatures, which is related to polaron relaxation. The temperature dependence of the bulk dc conductivity indicates a variable-range-hopping mechanism. The dielectric relaxation frequency deviates from the Arrhenius behavior. An equivalent circuit is used to explain qualitatively the experimental data of $\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}$.