Influence of grain size and structural changes on the electrical properties of nanocrystalline zinc ferrite
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- N. Ponpandian
- Materials Science Center, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025, India
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- A. Narayanasamy
- Materials Science Center, Department of Nuclear Physics, University of Madras, Guindy Campus, Chennai 600 025, India
書誌事項
- 公開日
- 2002-09-01
- DOI
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- 10.1063/1.1498883
- 公開者
- AIP Publishing
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説明
<jats:p>The electrical conductivity and dielectric properties of nanocrystalline zinc ferrite with various grain sizes ranging from 7 to 115 nm have been studied over a wide frequency range 1 Hz–15 MHz by impedance measurements in the temperature range of 300–650 K. The effect of grain size on the conductivity has been investigated by nonlinear least-squares fitting of the impedance data. The conduction mechanism is found to be due to the hopping of both electrons and holes. The activation energies have been obtained from Arrhenius plots of the grain and the grain boundary conductions and their values are characteristic of the hopping of charge carriers. As the grain size decreases, the conductivity also decreases along with a small increase in the activation energy. The real part ε′ of the dielectric constant exhibits anomalous behavior, except for the 115 nm grain size sample, which has been accounted for based on the presence of both types of charge carriers. The dielectric loss factor also decreases as the grain size decreases and thus the relaxation frequency shifts toward lower values. The electrical modulus is fitted to a stretched exponential function and the results clearly indicate the presence of the non-Debye type of dielectric relaxation in these materials.</jats:p>
収録刊行物
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- Journal of Applied Physics
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Journal of Applied Physics 92 (5), 2770-2778, 2002-09-01
AIP Publishing