[9a-PA1-1~13] 9.4 Thermoelectric conversion

[9a-PA1-10] Control of lattice defect in Mg₂Sn single crystal by changing synthesis pressure

〇Wataru Saito¹, Kei Hayashi¹, Yuzuru Miyazaki¹ (1.Tohoku univ.)

Keywords:thermoelectric material, Mg2Sn, lattice defects

Recently, we succeeded in analyzing lattice defects in Mg₂Sn: a small amount of Mg vacancies (V_Mg) existed. Since V_Mg is an accepter-type defect, it is considered that the hole carrier concentration increases with increasing the amount of V_Mg. In this report, we tried to control of lattice defect in Mg₂Sn single crystal by changing synthesis pressure. Mg₂Sn single crystals were prepared by using the melt growth method under (A) vacuum, (B) Ar 0.6 atm, and (C) Ar 1.3 atm. The Seebeck coefficient values at room temperature of the single crystal gradually decreased with increasing Ar pressure. These results sugested that the amount of V_Mg increases with increasing the Ar pressure.