Thermoelectric properties of one-dimensional cobalt oxide Ca3CoO6 and the effect of Zn doping

We conducted a systematic study of the electrical resistivity (□) and the Seebeck coefficient (S) on polycrystalline samples of Ca₃Co₂-XZn_xO₆ with x up to 0.1. We observed that ρ decreases monotonically with increasing temperature for all compositions. The resistivity decreased with Zn doping and the x=0.1 sample exhibited the lowest ρ. However, the Seebeck coefficient of this sample was almost the same as that of the non-doped one at high temperatures. Consequently, the power factor (=S²/ρ) of this sample was the largest among the studied samples, and was 1.7 times larger than that of the non-substituted one.