Thermoelectric power of soft carbons between 4.2 and 280 K in relation to phonon drag effect

✍ Scribed by Y. Hishiyama; A. Ono

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 677 KB
• Volume: 19
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(81)90027-0

✦ Synopsis

The thermoelectric power of soft carbons heat-treated to temperatures between 1700 and 3ooo"C was investigated between 4.2 and 280K. It was confirmed by X-ray and magnetoresistance measurements that the layer ordering was turbostratic for the samples heat-treated below 1900°C and it was graphitic for the samples heat-treated above 2100°C. The turbostratic specimens show a positive thermoelectric power which increases almost linearly with temperature. The graphitic specimens show a negative peak in the range between 20 and 35 K in the thermoelectric power versus temperature relationship. The temperature dependence of the thermoelectric power for these specimens can be classified into two distinct types in terms of heat treatment temperature. However, turbostratic specimens show no negative peak. The negative peak observed for graphitic specimens can be related to the phonon drag effect due to the coupling between carriers and long wave-length in-plane phonons, which is explained by the theory of phonon drag effect in graphite developed by Sugihara.