Anomalous physical properties of cerium-lanthanum filled skutterudites

Thermoelectric materials generate an electromotive force when submitted to a thermal gradient with an efficiency scaled by the so-called figure of mer it: Z = alpha (2)sigma/kappa, where cu is the Seebeck coefficient, sigma th e electronic conductivity and kappa the thermal conductivity. Theoretical c onsiderations have shown that a large value of Z requires not only a small value of kappa but also a large effective mass of charge carriers. The firs t condition is met in filled skutterudites, which have been studied extensi vely for this reason. The second condition suggests we focus our attention on skutterudites filled with an anomalous rare-earth element such as cerium , presenting heavy fermion characteristics. In this context, we report in t his paper a study of the magnetic properties of CeFe4Sb12 and their evoluti on upon cerium dilution. (C) 2001 Elsevier Science B.V. All rights reserved .