Microstrucutre and thermoelectric properties of rapidly prepared Sn1−xMnxTe alloys

Sn 1−x Mn x Te (x = 0, 0.09, 0.15, 0.20) bulk materials were prepared by melt spinning combined with spark plasma sintering process. Nanoscale grains were obtained, and the solid solubility of Mn was much enhanced by the ultrafast-cooling synthesis technique. The maximum of Seebeck coefficient and power factor are 242 µVK −1 and 19.97 µW cm −1 K −2 at 873 K with the doping concentration of 15 at% Mn. A large amount of grain boundaries and doped atoms improve the scattering of heat-carrying phonons in a wide range of frequencies, and the scattering mechanisms are also explained by theoretical calculation. As a result, the minimum of lattice thermal conductivity is 0.66 µVK −1 at 873 K, the corresponding figure of merit is 1.26 for Sn 0.85 Mn 0.15 Te sample. This value is improved by 35% comparing with previously reported result. Our work indicates that melt spinning process is effective to develop SnTe related thermoelectric materials with excellent thermoelectric properties, which has the widespread commercial value and the prospects for development.