Electrical properties of Dy3+/Na+ Co-doped oxide thermoelectric [Ca1-x(Na1/2Dy1/2)x]MnO3 ceramics

Abstract A new Dy 3+ /Na + co-doping system was attempted for improving the thermoelectric properties of CaMnO 3 system in this paper. [Ca 1-x (Na 1/2 Dy 1/2 ) x ]MnO 3 samples were produced by the solid state reaction method, and the electrical properties and the microstructure were investigated. The X-ray diffraction data and tolerant factor were obtained, indicating the second phase and the geometric distortion in this system. Besides, compared with the resistivity and the Seebeck coefficient of single Dy-doped system, Dy 3+ /Na + co-doping method could partially decrease the variation of carrier concentration as our expectation. More specifically, the holes introduced by doping Na + could compensate electrons introduced by doping Dy 3+ , leading to a low variation of carrier concentration. As the result, a relatively high Seebeck coefficient (−251.6 μV/K) and a relatively low resistivity (8.7  mΩ cm) were gained in this system, and the highest power factor value of 298.0 μW/K 2 m was obtained at 323 K in [Ca 0.95 (Dy 1/2 Na 1/2 ) 0.05 ]MnO 3 .