Resistivity and thermopower of CaB6 single crystal

The resistivity p and thermopower S of CaB6 single crystal have been measured at temperatures from 2 to I 100 K in magnetic fields up to 15 T. Temperature dependence of rho is expressed as [rho(T) - rho(0)] proportional to exp [-(T*/T)(1/2)] for Tless than or equal to90 K and T-1.7 for 90 K less than or equal to T less than or equal to 1100 K, where rho(0) = 232 muOmega cm. The magnitude of rho and S is very large suggesting thin concentration of carriers. The temperature dependence of them suggests the conduction is metallic and electron type. rho and S can be fitted on the basis of free electron model and obtained the Fermi level is situated near the bottom of an electron band with the Fermi energy of 80 K. The experimental and fitting results show this compound is semi-metallic. No scattering anomalies in temperature dependence of rho were observed and also no sudden change of the Fermi surface accompanied with magnetic transition in S above 100 K including the region where it might be considered to have ferromagnetic transition. (C) 2003, Elsevier Science B.V. All rights reserved.