Effects of partial substitution of Co by Ni on structural and transport properties of TiCoSb-based half-Heusler compound

Correlation amid structural and transport properties of TiCo(1−x)Ni x Sb, (x=0.00, 0.02, 0.04, 0.06) alloy have been investigated. Samples have been synthesized by solid state reaction method, followed by arc-melting. Minute amount of CoTi embedded phase has been revealed by in-depth structural characterization using Rietveld refinement. Unit cell volume decreases with increasing Ni in TiCo(1−x)Ni x Sb, indicate sucessful substitution. Lattice strain, crystalline size and dislocation density have been estimated from x-ray diffraction data. Temperature dependent resistivity (ρ(T)) measurements have been carried out down to 10 K. Transition from metallic to semiconducting behavior is observed in ρ(T) data for x=0.00, 0.02. ρ(T) for x=0.04 and 0.06 show metallic nature. Plausible explanation have been provided on the basis of position of Fermi surface and embedded phases.