| 학회 |
한국재료학회 |
| 학술대회 |
2013년 봄 (05/23 ~ 05/24, 여수 엠블호텔(THE MVL)) |
| 권호 |
19권 1호 |
| 발표분야 |
C. 에너지/환경 재료(Energy and Environmental Materials) |
| 제목 |
Effect of Acceptor and Donor Doping on Defect Chemistry and Electrical Conduction in Barium Zirconantes |
| 초록 |
Acceptor and donor doped complex perovskites Ba(Zr0.9M0.1)O3±δ (M=Y3+, Nb5+, Ta5+) as well as undoped BaZrO3 were prepared by a solid state reaction at 1550-1700°C. The high frequency impedance response of BZO ceramic is suggested to represent the oxide ion conductivity. The total resistance mainly originating from the large grain boundary effects are attributed to the electron hole conduction. The substitution of pentavalent Nb5+ and Ta5+ resulted in the larger optical band gap than the pristine zirconates. No indication of the reduction of the transition metals was found, which suggests the pentavalent substitution results in the generation of cation vacancies. This suppresses oxygen vacancies greatly thus the zirconates becomes pure p-type insulators, and the p-type conductivity was found comparable to that of the prinstine zirconates. On the other hand acceptor-doping in BaZrO3 produces oxygen vacancies which also becomes protonic carriers upon water incorporation. Similarly as in undoped BaZrO3, Ba(Zr0.9Y0.1)O3±δ exhibits very large ‘grain boundary’ resistance, which is however ascribed to the electron hole contribution due to the ion-blocking nature of grain boundaries. The activation energy was comparable to the undoped and donor-doped barium zirconates. Higher yttrium concentration increases hole conduction and decrease the activation energy of small polaron hopping. |
| 저자 |
Young-Hun Kim1, Dieu Nguyen2, Jee-Hoon Kim1, Eui-Chol Shin2, Young-Il Kim1, John Fisher2, Jong-Sook Lee1
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| 소속 |
1School of Materials Science and Engineering, 2Chonnam National Univ. |
| 키워드 |
BZY |
| E-Mail |
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