Thermoelectric properties of Sm1−xLaxBaCuFeO5 ceramics

• Systematical studies on the thermoelectric properties of SmBaCuFeO5 are few.
• The electrical conductivity has been increased about 2 orders of magnitude.
• A rough measurement of band gap of this class ceramic for the first time.
• As oxide thermoelectric materials, the thermal conductivity is relatively low.
• The maximum ZT of 0.042 at 1023 K is obtained for Sm0.6La0.4BaCuFeO5.

La-doped SmBaCuFeO5 polycrystalline ceramics have been prepared through sol–gel method followed by solid-state sintering reaction. A significant enhancement in the thermoelectric properties of SmBaCuFeO5 has been achieved by La doping. Our results reveal that the La doping can lead to a remarkable increase in the electrical conductivity of 2 orders of magnitude. The Seebeck coefficient decreases with increasing La content, which is consistent with the increased electrical conductivity. Thermal conductivity at room temperature decreases from 2.1 W m−1 K−1 to 1.7 W m−1 K−1 due to the existence of nano-sized grains in the high substitutive content samples. The maximum ZT of 0.042 at 1023 K is obtained for Sm0.6La0.4BaCuFeO5, which is 13 times more than that of the pristine sample.

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