Thermoelectric properties of Co-,Ir-, and Os-doped FeSi alloys: Evidence for strong electron-phonon coupling
- ORNL
The effects of various transition-metal dopants on the electrical and thermal transport properties of Fe{sub 1-x}M{sub x}Si alloys (M = Co, Ir, Os) are reported. The maximum thermoelectric figure of merit ZT{sub max} is improved from 0.007 at 60 K for pure FeSi to ZT = 0.08 at 100 K for 4% Ir doping. A comparison of the thermal conductivity data among Os-, Ir-, and Co-doped alloys indicates strong electron-phonon coupling in this compound. Because of this interaction, the common approximation of dividing the total thermal conductivity into independent electronic and lattice components (K{sub total} = K{sub electronic} + K{sub lattice}) fails for these alloys. The effects of grain size on thermoelectric properties of Fe{sub 0.96}Ir{sub 0.04}Si alloys are also reported. The thermal conductivity can be lowered by {approx}50% with little or no effect on the electrical resistivity or Seebeck coefficient. This results in ZT{sub max} = 0.125 at 100 K, still approximately a factor of 5 too low for solid-state refrigeration applications.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1010577
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 12; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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