Anomalous barium filling fraction and n-type thermoelectric performance of Ba{sub y}Co{sub 4}Sb{sub 12}
Barium-filled skutterudites Ba{sub y}Co{sub 4}Sb{sub 12} with an anomalously large filling fraction of up to y=0.44 have been synthesized. The lattice parameters increase linearly with Ba content. Magnetic susceptibility data show that Ba{sub 0.44}Co{sub 4}Sb{sub 12} is paramagnetic, which implies that some of the Co atoms in Ba{sub y}Co{sub 4}Sb{sub 12} have acquired a magnetic moment. The presence of the two different valence states of Co (Co{sup 3+} and Co{sup 2+}) leads to the anomalously large barium filling fraction even without extra charge compensation. All samples show n-type conduction. The electrical conductivity increases with increasing the Ba filling fraction. The lattice thermal conductivity of Ba{sub y}Co{sub 4}Sb{sub 12} is significantly depressed as compared to unfilled Co{sub 4}Sb{sub 12}. The dimensionless thermoelectric figure of merit, ZT, increases with increasing temperature reaching a maximum value of 1.1 for Ba{sub 0.24}Co{sub 4}Sb{sub 12} at 850 K. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40230548
- Journal Information:
- Journal of Applied Physics, Vol. 90, Issue 4; Other Information: DOI: 10.1063/1.1388162; Othernumber: JAPIAU000090000004001864000001; 007117JAP; PBD: 15 Aug 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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