Influence of Sn substitution on the thermoelectric properties in YbAl3

• Published in: Journal of alloys and compounds Vol. 600; pp. 8 - 12
• Main Authors: Li, J.Q., Liu, X.Y., Li, Y., Song, S.H., Liu, F.S., Ao, W.Q.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 05.07.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Conductivity phenomena in semiconductors and insulators; Electronic transport in condensed matter; Exact sciences and technology; Physics; Sn substitution; Thermoelectric properties; YbAl3 compound; YbAl3 compound; Sn substitution; Thermoelectric properties; Annealing; Electrical conductivity; Seebeck effect; compound; Ytterbium alloys; Tin alloys; Spark plasma sintering; Aluminium alloys; Solid solutions; Thermoelectric power; Thermal conductivity; Chemical composition; Carrier mobility; Carrier density; YbAl; Figure of merit
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2014.02.112

•The solid solutions YbAl3−xSnx with x up to 0.50 were prepared.•The thermal conductivity reduces significantly with the Sn substitution.•The thermoelectric properties of the solutions enhanced by proper Sn substitution.•The maximum ZT of 0.27 was obtained in the YbAl2.90Sn0.10 at 300K. The compound YbAl3 exhibits a very high power factor, but also rather a large thermal conductivity, leading to a low figure of merit. The solid solutions YbAl3−xSnx with x=0, 0.05, 0.10, 0.20, 0.30 and 0.50 were synthesized by high frequency induction melting, spark plasma sintering (SPS) and annealing treatment. The influence of Sn substitution on the thermoelectric properties of YbAl3 was investigated. The carrier concentration increases but the carrier mobility decreases with increasing x. The electrical resistivity of the sample does not increase apparently with increasing Sn content x until 0.10 but increases evidently with further increasing Sn content x. The absolute Seebeck coefficient increases with increasing Sn content x until 0.20 while the thermal conductivity decreases significantly with increasing x. As a result, the figure of merit ZT can be enhanced by the substitution of Sn for Al. The maximum ZT of 0.27 could be obtained in the YbAl2.90Sn0.10 at 300K, which is larger than 0.18 for the pure YbAl3 or 0.19 for the Sc-doped YbAl3.