Year: 2010
Type: article
Abstract: Clathrates are candidate materials for thermoelectric applications because of a number of unique properties. The clathrate I phases in the Ba-Ni-Ge ternary system allow controlled variation of the charge carrier concentration by adjusting the Ni content. Depending on the Ni content, the physical properties vary from metal-like to insulator-like and show a transition from p -type to n -type conduction. Here we present first results on the characterization of millimeter-sized single crystals grown by the Bridgman technique. Single crystals with a composition of Ba 8 Ni 3.5 Ge 42.1 □ 0.4 show metallic behavior (d ρ /d T > 0) albeit with high resistivity at room temperature [ ρ (300 K) = 1 mΩ cm]. The charge carrier concentration at 300 K, as determined from Hall-effect measurements, is 2.3 e − /unit cell. The dimensionless thermoelectric figure of merit estimated at 680 K is ZT ≈ 0.2.
Source: Journal of Electronic Materials
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,390
OpenAlex ID: W2000927767