Abstract
We report measurements of the dielectric response due to ionic relaxation in alkali germanate glasses (Li2O)x(Na2O)y(GeO2)1-x-y. The relaxation is investigated in both electric modulus and ac conductivity formalisms, between which important discrepancies are observed. In single alkali glasses, the width of the electric modulus decreases with decreasing alkali concentration. However, the power law dispersion of the ac conductivity scales regardless of the alkali concentration. This scaling property of the ac conductivity implies that inter-ionic interactions are not responsible for the non-Debye relaxation. In mixed alkali glasses, the exponent of the power law dispersion of the ac conductivity decreases and the dielectric relaxation strength increases relative to the single alkali glasses. With increasing total alkali concentration in the mixed alkali glasses, the frequency of maximum dielectric loss decreases, approaching frequencies comparable to that of the mixed alkali mechanical loss peak. These findings indicate a transition of the ionic relaxation toward a slower polarization process which is consistent with site memory mechanisms recently proposed for the mixed alkali effect.
| Original language | English |
|---|---|
| Pages (from-to) | 67-77 |
| Number of pages | 11 |
| Journal | Journal of Non-Crystalline Solids |
| Volume | 255 |
| Issue number | 1 |
| DOIs | |
| State | Published - Sep 1999 |
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All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Electronic, Optical and Magnetic Materials
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Evidence for site memory effects in the ionic relaxation of (Li2O)x(Na2O)y(GeO2)1-x-y glasses. / Sidebottom, David L.
In: Journal of Non-Crystalline Solids, Vol. 255, No. 1, 09.1999, p. 67-77.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Evidence for site memory effects in the ionic relaxation of (Li2O)x(Na2O)y(GeO2)1-x-y glasses
AU - Sidebottom, David L.
PY - 1999/9
Y1 - 1999/9
N2 - We report measurements of the dielectric response due to ionic relaxation in alkali germanate glasses (Li2O)x(Na2O)y(GeO2)1-x-y. The relaxation is investigated in both electric modulus and ac conductivity formalisms, between which important discrepancies are observed. In single alkali glasses, the width of the electric modulus decreases with decreasing alkali concentration. However, the power law dispersion of the ac conductivity scales regardless of the alkali concentration. This scaling property of the ac conductivity implies that inter-ionic interactions are not responsible for the non-Debye relaxation. In mixed alkali glasses, the exponent of the power law dispersion of the ac conductivity decreases and the dielectric relaxation strength increases relative to the single alkali glasses. With increasing total alkali concentration in the mixed alkali glasses, the frequency of maximum dielectric loss decreases, approaching frequencies comparable to that of the mixed alkali mechanical loss peak. These findings indicate a transition of the ionic relaxation toward a slower polarization process which is consistent with site memory mechanisms recently proposed for the mixed alkali effect.
AB - We report measurements of the dielectric response due to ionic relaxation in alkali germanate glasses (Li2O)x(Na2O)y(GeO2)1-x-y. The relaxation is investigated in both electric modulus and ac conductivity formalisms, between which important discrepancies are observed. In single alkali glasses, the width of the electric modulus decreases with decreasing alkali concentration. However, the power law dispersion of the ac conductivity scales regardless of the alkali concentration. This scaling property of the ac conductivity implies that inter-ionic interactions are not responsible for the non-Debye relaxation. In mixed alkali glasses, the exponent of the power law dispersion of the ac conductivity decreases and the dielectric relaxation strength increases relative to the single alkali glasses. With increasing total alkali concentration in the mixed alkali glasses, the frequency of maximum dielectric loss decreases, approaching frequencies comparable to that of the mixed alkali mechanical loss peak. These findings indicate a transition of the ionic relaxation toward a slower polarization process which is consistent with site memory mechanisms recently proposed for the mixed alkali effect.
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U2 - 10.1016/S0022-3093(99)00425-1
DO - 10.1016/S0022-3093(99)00425-1
M3 - Article
VL - 255
SP - 67
EP - 77
JO - Journal of Non-Crystalline Solids
JF - Journal of Non-Crystalline Solids
SN - 0022-3093
IS - 1
ER -