Abstract:
Measurements of DC electrical resistivity and Seebeck coefficient on the perovskite system La1-x Pb x-δ Co1-x Ti x O3-δ for 0·2≤x≤0·9 have been made in the temperature range 300-800 K. AC conductivity, σ a.c, of all the samples were measured as a function of temperature (300-573 K) and frequency (1 kHz-1 MHz). DC resistivity behaviour of all the samples is similar. However, the resistivity value, which varies over 5-6 orders of magnitude, depends on both the composition x and the structure of the samples. All the samples exhibit p-type electronic conduction. The value of Seebeck coefficient, α, for samples with x≤0·5 initially increases with temperature up to a particular temperature. Above this temperature, the behaviour of α for samples with x≤0·5 and for samples with x>0·5 over the entire temperature range is similar to that of La CoO3. All the samples exhibit frequency-dependent a.c. conductivity at low temperatures. © 1987 the Indian Academy of Sciences.
