Local Structure of Heusler‐Type Fe2V1−XTaXAl Thermoelectric Materials Studied by X‐Ray Absorption Fine‐Structure Spectroscopy

The local structure around doping Ta atoms in Fe2V1−xTaxAl alloys is investigated using X‐ray absorption fine‐structure (XAFS) and synchrotron radiation X‐ray diffraction (SR‐XRD) measurements to elucidate the origin of the reduction in their thermal conductivity. XAFS and SR‐XRD results show that with the substitution of Ta atoms at the V site, local strain exists around the doped Ta atoms. The reduction in the thermal conductivity due to Ta doping in the Fe2V1−xTaxAl alloys is attributed to the increase in the average atomic mass substituted with the heavy element Ta as well as the existence of the local strain. The local structure around doping Ta atoms in Fe2V1−xTaxAl alloys is investigated using X‐ray absorption fine‐structure (XAFS) and synchrotron radiation X‐ray diffraction measurements (SR‐XRD). The reduction in thermal conductivity due to Ta doping in the Fe2V1−xTaxAl alloys is attributed to the increase in the average atomic mass substituted with the heavy element Ta as well as the existence of local strain.