Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses
The melt-quenching technique was used to prepare tellurovanadate glasses containing sodium and potassium oxides with compositions of xNa2O-(20-x)K2O-30V2O5-50TeO2 (x = 0–20 mol%) to examine the impact of mixed-alkali oxide on alternating-current (AC) conductivity and dielectric properties. Structura...
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| Format: | Article |
| Language: | English |
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Elsevier
2020-03-01
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| Series: | Results in Physics |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2211379719326749 |
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| author | S.J. Japari A.K. Yahya R. Hisam |
| author_facet | S.J. Japari A.K. Yahya R. Hisam |
| author_sort | S.J. Japari |
| collection | DOAJ |
| description | The melt-quenching technique was used to prepare tellurovanadate glasses containing sodium and potassium oxides with compositions of xNa2O-(20-x)K2O-30V2O5-50TeO2 (x = 0–20 mol%) to examine the impact of mixed-alkali oxide on alternating-current (AC) conductivity and dielectric properties. Structural analysis revealed the presence of bridging oxygen (BO) and non-bridging oxygen (NBO). Thermal analysis results demonstrated a minimum value of glass transition temperature (Tg) at x = 10 mol% with an increase in Na2O content. The variation of AC conductivity (σac) revealed a non-linear behaviour with Na2O at temperature < 383 K, where σac increased to maximum value at x = 15 mol% and shifted to x = 10 mol% at temperature ≥ 383 K. This result may be attributed to mixed-alkali effect (MAE) because of the mixing of the two alkali oxides. The increase in σac with Na2O might be due to increase in the carrier pathway caused by the opening up of the glass network as NBO increased. Meanwhile, dielectric constant (ε') demonstrated an optimal increase at x = 10 mol% prior to the reduction greater than x = 10 mol%. The maximum ε' value at x = 10 mol% was in accordance with the σac anomaly, which may also related to the MAE that induced formation of heavy dipoles. Consequently, this facilitated the dipole orientation in the glass network. Conduction mechanism at the dispersion region for all glass samples was found to be the correlated barrier hopping (CBH) model. The electrical modulus of the investigated samples revealed the non-Debye type relaxation, which indicates presence of interaction between ions. |
| first_indexed | 2024-04-12T08:22:27Z |
| format | Article |
| id | doaj.art-c2de3176f82041aa99f3cdb6f8dad378 |
| institution | Directory Open Access Journal |
| issn | 2211-3797 |
| language | English |
| last_indexed | 2024-04-12T08:22:27Z |
| publishDate | 2020-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Physics |
| spelling | doaj.art-c2de3176f82041aa99f3cdb6f8dad3782022-12-22T03:40:31ZengElsevierResults in Physics2211-37972020-03-0116102905Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glassesS.J. Japari0A.K. Yahya1R. Hisam2Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, MalaysiaFaculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, MalaysiaCorresponding author.; Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, MalaysiaThe melt-quenching technique was used to prepare tellurovanadate glasses containing sodium and potassium oxides with compositions of xNa2O-(20-x)K2O-30V2O5-50TeO2 (x = 0–20 mol%) to examine the impact of mixed-alkali oxide on alternating-current (AC) conductivity and dielectric properties. Structural analysis revealed the presence of bridging oxygen (BO) and non-bridging oxygen (NBO). Thermal analysis results demonstrated a minimum value of glass transition temperature (Tg) at x = 10 mol% with an increase in Na2O content. The variation of AC conductivity (σac) revealed a non-linear behaviour with Na2O at temperature < 383 K, where σac increased to maximum value at x = 15 mol% and shifted to x = 10 mol% at temperature ≥ 383 K. This result may be attributed to mixed-alkali effect (MAE) because of the mixing of the two alkali oxides. The increase in σac with Na2O might be due to increase in the carrier pathway caused by the opening up of the glass network as NBO increased. Meanwhile, dielectric constant (ε') demonstrated an optimal increase at x = 10 mol% prior to the reduction greater than x = 10 mol%. The maximum ε' value at x = 10 mol% was in accordance with the σac anomaly, which may also related to the MAE that induced formation of heavy dipoles. Consequently, this facilitated the dipole orientation in the glass network. Conduction mechanism at the dispersion region for all glass samples was found to be the correlated barrier hopping (CBH) model. The electrical modulus of the investigated samples revealed the non-Debye type relaxation, which indicates presence of interaction between ions.http://www.sciencedirect.com/science/article/pii/S2211379719326749AC conductivityDielectric propertiesMixed-alkali effectTellurite glasses |
| spellingShingle | S.J. Japari A.K. Yahya R. Hisam Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses Results in Physics AC conductivity Dielectric properties Mixed-alkali effect Tellurite glasses |
| title | Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses |
| title_full | Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses |
| title_fullStr | Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses |
| title_full_unstemmed | Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses |
| title_short | Effects of mixed-alkali oxides on AC conductivity and dielectric properties of xNa2O-(20-x)K2O-30V2O5-50TeO2 glasses |
| title_sort | effects of mixed alkali oxides on ac conductivity and dielectric properties of xna2o 20 x k2o 30v2o5 50teo2 glasses |
| topic | AC conductivity Dielectric properties Mixed-alkali effect Tellurite glasses |
| url | http://www.sciencedirect.com/science/article/pii/S2211379719326749 |
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