Transport properties of Eu containing clathrates

A. Bentien, V. Pacheco, S. Paschen, M. Baenitz, Yu. Grin, F. Steglich

Max Planck Institute for Chemical Physics of Solids, Nötnitzer Str. 40, 01187 Dresden, Germany

Transport properties of several type I and type IIIV Eu containing clathrates with small variations in the stoichiometry of the framework atoms Ge/Ga will be presented. It will be shown that the varying properties among samples with the same structure can be understood in terms of a rigid band model where only the charge carrier concentration is changed. For samples with different structure the differences can be explained by a slightly enhanced effective band mass in the type I clathrate when compared to the type IIIV structure. Finally, the potential of Eu containing clathrates for thermoelectric applications will be discussed.