Phase formation and electrical conductivity of Ba-doped LaScO3

초록

Phase formation and conduction behavior in BaO-doped LaSCO3 with the perovskite structure have been investigated. The structures of La1-xBaxScO3-delta were analyzed to be cubic for La0.6Ba0.4ScO3-delta and La0.5Ba0.5ScO3-delta, a mixture of cubic and orthorhombic for La0.9Ba0.1ScO3-delta, La0.8Ba0.2ScO3-delta and La(0.7)Ba(0.3)Sco(3-delta), and orthorhombic for La0.95Ba0.05ScO3-delta. La1-xBaxScO3-delta showed a pure oxide-ion conduction below intermediate oxygen partial pressures under dry atmosphere. At high oxygen partial pressures, it exhibited mixed oxide-ion and p-type electronic conduction. In the presence of water vapor, proton conduction was observed due to the formation of protonic defects and the bulk conductivity by protons was highest in the composition of La0.5B0.5ScO2.75. The apparent activation energy for proton conduction was almost the same in each compound. 0.66-0.68 eV, despite the differences in crystal structure and A-site dopant concentration.

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