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Finite size effects on the electrical properties of sol-gel synthesized CoFe{sub 2}O{sub 4} powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects

Abstract

Fine particles of cobalt ferrite were synthesized by the sol-gel method. Subsequent heat treatment at different temperatures yielded cobalt ferrites having different grain sizes. X-ray diffraction studies were carried out to elucidate the structure of all the samples. Dielectric permittivity and ac conductivity of all the samples were evaluated as a function of frequency, temperature and grain size. The variation of permittivity and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type interfacial polarization in general, with a noted variation from the expected behaviour for the cold synthesized samples. High permittivity and conductivity for small grains were explained on the basis of the correlated barrier-hopping model.
Authors:
George, Mathew; [1]  Nair, Swapna S; [1]  Malini, K A; [1]  Joy, P A; [2]  Anantharaman, M R [1] 
  1. Department of Physics, Cochin University of Science and Technology, Cochin-682 022 (India)
  2. Physical Chemistry Division, National Chemical Laboratory, Pune-411 008 (India)
Publication Date:
Mar 21, 2007
Product Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physics. D, Applied Physics; Journal Volume: 40; Journal Issue: 6; Other Information: PII: S0022-3727(07)31458-7; DOI: 10.1088/0022-3727/40/6/001; Country of input: International Atomic Energy Agency (IAEA)
Subject:
36 MATERIALS SCIENCE; COBALT; COBALT OXIDES; DISPERSIONS; FERRITES; FREQUENCY DEPENDENCE; GRAIN SIZE; HEAT TREATMENTS; PARTICLES; PERMITTIVITY; POLARIZATION; POWDERS; SOL-GEL PROCESS; X-RAY DIFFRACTION
OSTI ID:
20927350
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0022-3727; JPAPBE; TRN: GB07P4725085932
Submitting Site:
GBN
Size:
page(s) 1593-1602
Announcement Date:
Nov 13, 2007

Citation Formats

George, Mathew, Nair, Swapna S, Malini, K A, Joy, P A, and Anantharaman, M R. Finite size effects on the electrical properties of sol-gel synthesized CoFe{sub 2}O{sub 4} powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects. United Kingdom: N. p., 2007. Web. doi:10.1088/0022-3727/40/6/001; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
George, Mathew, Nair, Swapna S, Malini, K A, Joy, P A, & Anantharaman, M R. Finite size effects on the electrical properties of sol-gel synthesized CoFe{sub 2}O{sub 4} powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects. United Kingdom. https://doi.org/10.1088/0022-3727/40/6/001; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
George, Mathew, Nair, Swapna S, Malini, K A, Joy, P A, and Anantharaman, M R. 2007. "Finite size effects on the electrical properties of sol-gel synthesized CoFe{sub 2}O{sub 4} powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects." United Kingdom. https://doi.org/10.1088/0022-3727/40/6/001; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@misc{etde_20927350,
title = {Finite size effects on the electrical properties of sol-gel synthesized CoFe{sub 2}O{sub 4} powders: deviation from Maxwell-Wagner theory and evidence of surface polarization effects}
author = {George, Mathew, Nair, Swapna S, Malini, K A, Joy, P A, and Anantharaman, M R}
abstractNote = {Fine particles of cobalt ferrite were synthesized by the sol-gel method. Subsequent heat treatment at different temperatures yielded cobalt ferrites having different grain sizes. X-ray diffraction studies were carried out to elucidate the structure of all the samples. Dielectric permittivity and ac conductivity of all the samples were evaluated as a function of frequency, temperature and grain size. The variation of permittivity and ac conductivity with frequency reveals that the dispersion is due to Maxwell-Wagner type interfacial polarization in general, with a noted variation from the expected behaviour for the cold synthesized samples. High permittivity and conductivity for small grains were explained on the basis of the correlated barrier-hopping model.}
doi = {10.1088/0022-3727/40/6/001; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)}
journal = []
issue = {6}
volume = {40}
place = {United Kingdom}
year = {2007}
month = {Mar}
}