The effect of V substitution on the properties of CoTiSb

Electrical resistivity, structural and magnetic properties of polycrystalline samples of a half-Heusler alloy, CoTiSb, and the effect of the substitution of V for Ti on these properties in CoTi1-xVxSb have been investigated. The temperature dependence of the electrical resistivity in CoTiSb above 10K is found to exhibit, on the whole, semiconducting behavior, which agrees with previous results. For samples in which V is substituted for Ti with x=<0.1 the structure is found to be the half-Heusler type as with x=0. As V increases from x=0 to 0.05, the magnitude of the resistivity increases, but the temperature dependence is similar to that of x=0. For the sample with x=0.1, however, the magnitude of the resistivity suddenly decreases to the value smaller than that of x=0, and the slope of the temperature dependence of the resistivity becomes positive down to 25K