Polycrystalline mixed crystals of LaNi
xCo
1-xO
3 are prepared over the whole range of
x. X-ray observation revealed that all the samples prepared at 1000°C possess the same perovskite lattice as that of LaCoO
3. Among these perovskite type crystals, those of 0_??_
x<0.5 are stable up to 1500°C and that of
x=0.5 is stable up to 1300°C. Resistivity ρ and thermoelectric power are measured as functions of temperature (77°_??_500°K) on samples of 0_??_
x_??_0.5 sintered at 1300°C. At 300°K, Hall voltage is not found for samples of
x=0.4 and 0.5. Log(ρ/T)
vs. 1/T is a kinked straight line (for
x_??_0.2) or simple straight line (for
x>0.2) and values of both ρ and activation energy decrease appreciably with increasing
x. From these properties, a conclusion is drawn that the current in the samples is carried by hopping diffusion of localized electrons and/or holes between Co
3+ and Co
4+ or between Ni
2+ and Ni
3+.
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