Directional Solidification and Thermoelectric Properties of Undoped Mg2Sn Crystal

• Published in: Journal of electronic materials Vol. 45; no. 6; pp. 2895 - 2903
• Main Authors: Li, Xin, Li, Shuang-ming, Feng, Song-ke, Zhong, Hong, Fu, Heng-zhi
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.06.2016
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Solid State Physics; Crystal growth; high-temperature-gradient directional solidification; Mg; Sn; thermoelectric properties
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-015-4320-5

Single-phase Mg 2 Sn crystal has been successfully directionally solidified from the melt with a high temperature gradient of 185 K cm −1 . The solidified distance for the growth of single-phase Mg 2 Sn crystal was predicted theoretically and agreed well with the experimental result. The grown Mg 2 Sn crystals exhibit better thermoelectric performance and high thermoelectric figure of merit along the growth direction. In the temperature range from 300 K to 700 K, the maximum Seebeck coefficient S and electrical conductivity σ reached −261  μ V K −1 and 525 Ω −1  m −1 , respectively. The minimum thermal conductivity κ was measured to be 4.3 W m −1  K −1 , and the lattice thermal conductivity approximated 90% of the bulk thermal conductivity of the crystal. The method developed in this work provides a methodological reference for preparation of Mg 2 B IV and its doped and solid-solution compounds.