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Title: Impedance analysis of MnCoCuO NTC ceramic

Abstract

Impedance spectroscopy is often used to analyse the electrical properties of ceramic materials having high-resistive grain boundaries, such as ZnO and SrTiO{sub 3}. Fewer attempts have been made at using this technique for the analysis of inhomogeneous electronic ceramics consisting of grains with differing composition, such as those occurring in negative temperature coefficient (NTC) thermistors. In this study, we have attempted to adopt ac impedance spectroscopy together with other techniques to analyse an NTC thermistor ceramic material. An Mn, Co and Cu multielements transition metal oxide (MnCoCuO) ceramic was prepared by using homogeneous precipitation employing oxalic acid. This material displayed a typical NTC effect, showing an electrical resistance decrease with temperature when dc electrical measurement was performed. The ac impedance spectroscopy analysis showed that there were two peaks in impedance and conductance versus frequency plot. By using an alternative representation of impedance spectra Z'/f versus Z', three distinct relaxation frequency ranges were identified. They are believed to originate, respectively, from the electrode, phase 1 (rich-Cu phase) and phase 2 (poor-Cu phase) grains existing in this ceramic. SEM observation and EDX analysis clearly showed existence of two distinct phase grains. The resistance values were derived from phases 1 and 2 grainsmore » based on ac impedance data. The sum of the resistance values was in good agreement with that from dc measurement in the temperature range of 30-95 deg. C. The material constant, B, for the two phases was also calculated, giving 3100 and 3600 K for phases 1 and 2, respectively.« less

Authors:
 [1];  [2];  [1]
  1. Thin Film Centre, University of Paisley, PA1 2BE Paisley (United Kingdom)
  2. Microscale Sensor Group, University of Paisley, PA1 2BE Paisley (United Kingdom)
Publication Date:
OSTI Identifier:
20889793
Resource Type:
Journal Article
Journal Name:
Materials Research Bulletin
Additional Journal Information:
Journal Volume: 40; Journal Issue: 7; Other Information: DOI: 10.1016/j.materresbull.2005.04.001; PII: S0025-5408(05)00112-1; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0025-5408
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERAMICS; COBALT; COPPER OXIDES; ELECTRIC CONDUCTIVITY; FREQUENCY RANGE; GRAIN BOUNDARIES; IMPEDANCE; MANGANESE; OXALIC ACID; PRECIPITATION; SCANNING ELECTRON MICROSCOPY; SPECTROSCOPY; STRONTIUM TITANATES; TEMPERATURE COEFFICIENT; TEMPERATURE RANGE; THERMISTORS; ZINC OXIDES

Citation Formats

Song, S G, Ling, Z, and Placido, F. Impedance analysis of MnCoCuO NTC ceramic. United States: N. p., 2005. Web. doi:10.1016/j.materresbull.2005.04.001.
Song, S G, Ling, Z, & Placido, F. Impedance analysis of MnCoCuO NTC ceramic. United States. https://doi.org/10.1016/j.materresbull.2005.04.001
Song, S G, Ling, Z, and Placido, F. 2005. "Impedance analysis of MnCoCuO NTC ceramic". United States. https://doi.org/10.1016/j.materresbull.2005.04.001.
@article{osti_20889793,
title = {Impedance analysis of MnCoCuO NTC ceramic},
author = {Song, S G and Ling, Z and Placido, F},
abstractNote = {Impedance spectroscopy is often used to analyse the electrical properties of ceramic materials having high-resistive grain boundaries, such as ZnO and SrTiO{sub 3}. Fewer attempts have been made at using this technique for the analysis of inhomogeneous electronic ceramics consisting of grains with differing composition, such as those occurring in negative temperature coefficient (NTC) thermistors. In this study, we have attempted to adopt ac impedance spectroscopy together with other techniques to analyse an NTC thermistor ceramic material. An Mn, Co and Cu multielements transition metal oxide (MnCoCuO) ceramic was prepared by using homogeneous precipitation employing oxalic acid. This material displayed a typical NTC effect, showing an electrical resistance decrease with temperature when dc electrical measurement was performed. The ac impedance spectroscopy analysis showed that there were two peaks in impedance and conductance versus frequency plot. By using an alternative representation of impedance spectra Z'/f versus Z', three distinct relaxation frequency ranges were identified. They are believed to originate, respectively, from the electrode, phase 1 (rich-Cu phase) and phase 2 (poor-Cu phase) grains existing in this ceramic. SEM observation and EDX analysis clearly showed existence of two distinct phase grains. The resistance values were derived from phases 1 and 2 grains based on ac impedance data. The sum of the resistance values was in good agreement with that from dc measurement in the temperature range of 30-95 deg. C. The material constant, B, for the two phases was also calculated, giving 3100 and 3600 K for phases 1 and 2, respectively.},
doi = {10.1016/j.materresbull.2005.04.001},
url = {https://www.osti.gov/biblio/20889793}, journal = {Materials Research Bulletin},
issn = {0025-5408},
number = 7,
volume = 40,
place = {United States},
year = {Tue Jul 12 00:00:00 EDT 2005},
month = {Tue Jul 12 00:00:00 EDT 2005}
}