Electrical transport and thermoelectric properties of Ca 0.8 Y 0.2− x Dy x MnO 3−δ (0 ≤ x ≤ 0.2)

Ca 0.8 Y 0.2− x Dy x MnO 3−δ (0≤ x ≤0.2) samples were fabricated by the solid‐state reaction method, and their thermoelectric properties were studied from 500°C to 800°C. Upon the substitution of Dy 3+ for Y 3+ in the Ca 0.8 Y 0.2− x Dy x MnO 3−δ , the electrical and thermal conductivities gradually decreased with increasing Dy 3+ concentration, whereas the absolute value of the Seebeck coefficient significantly increased. The Ca 0.8 Dy 0.2 MnO 3−δ showed the largest value of dimensionless figure of merit (0.180) at 800°C as a result of the combination of the largest absolute value of the Seebeck coefficient and the lowest thermal conductivity. We believe that the Ca 0.8 Dy 0.2 MnO 3−δ is a promising thermoelectric material at high temperatures.