Nobre, MALLanfredi, S.2014-05-202014-05-202003-10-13Applied Physics Letters. Melville: Amer Inst Physics, v. 83, n. 15, p. 3102-3104, 2003.0003-6951http://hdl.handle.net/11449/31931The electric properties of the sodium niobate perovskite ceramic were investigated by impedance spectroscopy in the frequency range from 5 Hz to 13 MHz and from room temperature up to 1073 K, in a thermal cycle. Both capacitance and conductivity exhibit an anomaly at around 600 K as a function of the temperature and frequency. The electric conductivity as a function of angular frequency sigma(omega) follows the relation sigma(omega)=Aomega(s). The values of the exponent s lie in the range 0.15less than or equal tosless than or equal to0.44. These results were discussed considering the conduction mechanism as being a type of polaron hopping. (C) 2003 American Institute of Physics.3102-3104engArtigo10.1063/1.1618016WOS:000185832400038Acesso abertoWOS000185832400038.pdf7201928600704530