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Publication
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| Title of Article |
Non-ohmic properties and electrical responses of grains andgrain boundaries of Na1/2Y1/2Cu3Ti4O12 ceramics |
| Date of Acceptance |
12 September 2016 |
| Journal |
| Title of Journal |
Journal of the American Ceramic Society |
| Standard |
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| Institute of Journal |
Wiley Online Library |
| ISBN/ISSN |
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| Volume |
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| Issue |
100 |
| Month |
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| Year of Publication |
2017 |
| Page |
157-166 |
| Abstract |
The dielectric and non-Ohmic properties of Na1/2Y1/2Cu3Ti4O12 ceramics sintered
under various conditions to obtain different microstructures were investigated.
Microstructure analysis confirmed the presence of Na, Y, Cu, Ti, and O and these
elements were well dispersed in the microstructure. Na1/2Y1/2Cu3Ti4O12 ceramics
exhibited non-Ohmic characteristics with large nonlinear coefficients of about 5.7-
6.6 irrespectively of sintering conditions. The breakdown electric field of finegrained ceramic with the mean grain size of 1.7 lm (5600 V/cm) was much
larger than those of the course-grained ceramics with grain sizes of 9.5-10.4 lm
(1850-2180 V/cm). Through optimization of sintering conditions, a low loss
tangent of about 0.03 and very high dielectric permittivities of 18 000-23 000
with good temperature stability were successfully accomplished. The electrical
responses of the grains and grain boundaries can, respectively, be well described
using admittance and impedance spectroscopy analyses based on the brickwork
layer model. A possible mechanism for the origin of semiconducting grains is discussed. The colossal dielectric response was reasonably described as closely correlated with the electrically heterogeneous microstructure by means of strong
interfacial polarization at the insulating grain-boundary layers. The non-Ohmic
properties of Na1/2Y1/2Cu3Ti4O12 ceramics were primarily related to their
microstructure, ie, grain size and volume fraction of grain boundaries. |
| Keyword |
dielectric materials/properties, grain boundaries, impedance spectroscopy, microstructure, varistors |
| Author |
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| Reviewing Status |
มีผู้ประเมินอิสระ |
| Status |
ตีพิมพ์แล้ว |
| Level of Publication |
นานาชาติ |
| citation |
false |
| Part of thesis |
true |
| Attach file |
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| Citation |
0
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Journal Publication
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