PROBING ELECTRICAL-CONDUCTION BEHAVIOR OF BASNO3

The ac conductivity, sigma(ac) of BaSnO3 has been measured in the temp erature range 310-520 K and frequency range 100 Hz-1 MHz. Below 420 K the conductivity is almost independent of temperature while between 42 0 and 520 K it is temperature dependent. At 100 kHz the activation ene rgy of these two regions is 0.08 and 0.35 eV, respectively. It has bee n proposed that in the low temperature region conduction is due to hop ping of charge carriers among the Sn+2 and Sn+4 sites. In the high tem perature region conduction is due to excitation of charge carriers at the edges of the conduction band and hopping at energies close to it. Further impedance and modulus spectroscopy studies show that the condu ction mechanism is the same for grains and grain boundaries. (C) 1998 American Institute of Physics. [S0021-8979(98)02312-3]