Analysis of thermal conductivity in Ni-doped CoSb3

Co_1-xNi_xSb₃ (x = 0.005≈0.1) samples were prepared by direct melting of constituent elements in a graphite crucible and subsequently was sintered using spark plasma sintering. The temperature dependence of the Hall coefficient, Hall mobility, Seebeck coefficient, electrical resistivity and thermal conductivity were investigated in a temperature range from 20 to 773 K. All the measured samples are n-type semiconductor and the conduction type changes from n- to p-type at around 450 K. The temperature for the transition from n-type to p-type increased with increasing Ni content x. The scattering factor, Fermi energy and Lorenz number were estimated and thermal conductivity was analyzed as a function of temperature. The lattice component of thermal conductivity is dominant at low temperatures but carrier and bipolar components become large at temperatures higher than the transition temperature.