Synergistically Optimized Electrical and Thermal Transport Properties of CaMnO 3 via Doping High Solubility Sr

Herein, we show that we can synergistically optimize the electrical and thermal transport properties of CaMnO 3 via doping Sr. All the samples exhibit a single phase with an orthorhombic symmetry within the experimental doping range (0-10%). Sr doping significantly reduces resistivity while maintaining a relatively high absolute value of Seebeck coefficient, resulting in an effective enhancement in the electrical properties of the material. The maximum power factor (∼ 3.01 μ W cm −1 K −2 ) is achieved at 873 K for Ca 0.96 Sr 0.04 MnO 3 , which is three times larger than that of the un-doped CaMnO 3 . The thermal conductivity governed by lattice thermal conductivity is notably decreased compared with the un-doped sample, which is mainly attributed to the decreased grain size and large mass and strain fluctuations caused by Sr doping, and the thermal conductivity decreases with increasing Sr doping level. The enhanced power factor and significantly reduced thermal conductivity lead to a maximum ZT value of 0.15 at 873 K in the Ca 0.90 Sr 0.10 MnO 3 sample, indicating that CaMnO 3 is a potential candidate for high-temperature application.