Mechanism of the Electrical Conduction in Li-Doped NiO

The electrical conductivity and the Seebeck effect are measured in the temperature region of 100 to 1300°K in NiO doped with Li. From the results it is concluded that the mobility of the charge carriers involves no activation energy. The temperature dependence of the conductivity is almost completely determined by the charge-carrier concentration. In order to calculate from the measurements the mobility $\mu$ as a function of temperature, the behavior of the density of states $N_V$ must be known. $\mu$ has been calculated for two cases, viz., $N_V$ independent of temperature and $N_V$ proportional to $T^{\frac{3}{2}}$. The resulting values of $\mu$ at room temperature are 0.5 and 5 ${\mathrm{cm}}^2$/V sec, respectively. In the discussion the results of Hall-effect measurements are also considered.