Qin Nailing, Pang Yehai, Xu Zhengbing, Chen Xiyong, Yan Jialin
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, Nanning 530004, China.
Materials (Basel). 2023 Mar 23;16(7):2548. doi: 10.3390/ma16072548.
Double-layered manganites are natural superlattices with low thermal conductivity, which is of importance for potential thermoelectric applications. The GdSrMnO ( = 0.5; 0.625; 0.75) were prepared by the solid-state reaction method. All the samples crystallize in the tetragonal I4/mmm SrTiO type structure. The unit cell volume and the distortion in the MnO octahedra increase with increasing Gd content. Their thermoelectric properties were investigated between 300 and 1200 K. All exhibit an -type semiconducting behavior. The electrical conductivity () increases while the absolute value of the Seebeck coefficient (||) decreases with increasing Gd content. Simultaneous increases in and || with increasing temperature are observed at temperatures approximately higher than 600 K, and the power factor reaches a maximum value of 18.36 μW/(m K²) for = 0.75 at 1200 K. The thermal conductivity () is lower than 2 W/(m K) over the temperature range of 300-1000 K for all the samples and a maximum dimensionless figure of merit of 0.01 is obtained for = 0.75 at 1000 K.
双层锰酸盐是具有低热导率的天然超晶格，这对于潜在的热电应用具有重要意义。通过固态反应法制备了GdSrMnO（= 0.5；0.625；0.75）。所有样品均结晶为四方I4/mmm SrTiO型结构。MnO八面体中的晶胞体积和畸变随Gd含量的增加而增大。在300至1200 K之间研究了它们的热电性能。所有样品均表现出n型半导体行为。随着Gd含量的增加，电导率（σ）增大，而塞贝克系数的绝对值（|S|）减小。在大约高于600 K的温度下，观察到σ和|S|均随温度升高而增加，对于x = 0.75的样品，在1200 K时功率因数达到最大值18.36 μW/(m K²)。在300 - 1000 K的温度范围内，所有样品的热导率（κ）均低于2 W/(m K)，对于x = 0.75的样品，在1000 K时获得的最大无量纲品质因数ZT为0.01。
