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Issue 94, 2016, Issue in Progress
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Effects of DC bias on non-ohmic sample-electrode contact and grain boundary responses in giant-permittivity La1.7Sr0.3Ni1−xMgxO4 ceramics

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Abstract

The effects of DC bias on the giant dielectric properties and electrical responses of non-ohmic sample-electrode contact and grain boundaries of La1.7Sr0.3Ni1−xMgxO4 (x = 0–0.5) ceramics were studied. La1.7Sr0.3Ni1−xMgxO4 ceramics were prepared using a chemical combustion method with urea as a fuel. A pure phase and dense ceramic microstructure were achieved. Using impedance spectroscopy analysis under a DC bias, the giant dielectric properties of an un-doped La1.7Sr0.3NiO4 ceramic were found to be due to a combination of the small polaronic hopping mechanism and non-ohmic sample-electrode contact effect. This was confirmed by a linear Mott–Schottky plot of 1/C2 vs. DC bias voltage. Doping La1.7Sr0.3NiO4 ceramics with Mg2+ ions caused an increase in the grain boundary resistance, leading to a decrease in the loss tangent and degradation of the electrode effect. The giant dielectric response in La1.7Sr0.3Ni1−xMgxO4 ceramics (x = 0.3–0.5) was primarily attributed to the insulating grain boundary response (i.e., Maxwell–Wagner polarization) coupled with small polaronic hopping of charge carriers.

Graphical abstract: Effects of DC bias on non-ohmic sample-electrode contact and grain boundary responses in giant-permittivity La1.7Sr0.3Ni1−xMgxO4 ceramics

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Article information


Submitted
30 Jul 2016
Accepted
19 Sep 2016
First published
19 Sep 2016

RSC Adv., 2016,6, 91377-91385
Article type
Paper

Effects of DC bias on non-ohmic sample-electrode contact and grain boundary responses in giant-permittivity La1.7Sr0.3Ni1−xMgxO4 ceramics

K. Meeporn, N. Chanlek and P. Thongbai, RSC Adv., 2016, 6, 91377
DOI: 10.1039/C6RA19290D

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