Modification of the thermoelectric properties of CePd3 by the substitution of neodymium and thorium

The temperature dependence of transport properties, including thermopower, electrical resistivity and thermal conductivity, were measured on a series of Nd substituted CePd3 samples and Th substituted NdxCe1-xPd3 samples (x = 0.6, 0.7). The relatively large thermoelectric figure of merit (ZT) associated with the intermediate valence state of CePd3 is reduced for all NdxCe1-xPd3 samples and is primarily the result of reducing the thermopower at all temperatures. The ZT values of the NdxCe1-xPd3 samples (x = 0.6, 0.7) are increased, especially at low temperature (< 150 K), by replacing some of the NdxCe1-x with the larger, tetravalent Th. However, the ZT values never exceed that of the pure CePd3. For all compounds, the Lorentz ratios (L/L-o) are close to unity at room temperature and deviate to larger values as the temperature is lowered. (C) 1999 Elsevier Science Ltd. All rights reserved.