Thermoelectric Properties of Nanocomposite Heavy Fermion CeCu6

Abstract

Samples of heavy fermion compound CeCu6 were prepared by hot-press technique. Temperature-dependent (5-300 K) thermoelectric transport properties of the samples were measured. The dimensionless figure-of-merit (ZT) was optimized by varying the hot-pressing temperature. Our measurements of thermal conductivity show that the lowest hot pressing temperature (450 C) produces the lowest thermal conductivity. Electrical resistivity increases significantly while the Seebeck coefficient decreases with decrease in the hot pressing temperature. As the hot-pressing temperature decreases, electronic contribution to the total thermal conductivity decreased more rapidly than the lattice contribution did. As a result, for lower hot-pressing temperature the gain in thermal conductivity reduction was offset by the loss in power factor. Our ZT calculations show a broad peak with a maximum value of 0.024 at 60 K for the sample hot pressed at 800 C. The pronounced low-temperature ZT peak emphasizes the importance of this heavy fermion system as a potential p-type thermoelectric for solid state cooling applications.