High temperature transport properties of Ag-added (Ca0.975La0.025)3Co4O9 ceramics

✍ Scribed by Ying Song; Ce-Wen Nan

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 676 KB
• Volume: 406
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2011.05.006

✦ Synopsis

Ag-added (Ca 0.975 La 0.025 ) 3 Co 4 O 9 ceramics were fabricated using spark plasma sintering from the precursor powder synthesized by a polyacrylamide gel method. The results indicated that Ag precipitated as a second phase in Ca 3 Co 4 O 9 matrix. The addition of Ag was effective in enhancing the electrical conductivity and had a slight effect on Seebeck coefficient. In addition, the temperature dependence of electrical conductivity showed that the hole hopping conduction mechanism was dominant for the Ag-added (Ca 0.975 La 0.025 ) 3 Co 4 O 9 ceramics. The activation energy remained unchanged with the increasing Ag content. The thermoelectric power factor of Ag-added (Ca 0.975 La 0.025 ) 3 Co 4 O 9 ceramics reached about 5 Â 10 À 4 Wm À 1 K À 2 at 700 1C, suggesting a promising thermoelectric oxide candidate at high temperatures.