Effect of Microwave Sintering on Electrical Properties of Sr-deficient and Bi-rich Strontium Bismuth Niobate (Sr0.8Bi2.2Nb2O9) Ferroelectric Ceramic

Nonstoichiometric strontium bismuth niobate (Sr0.8Bi2.2Nb2O9: SBN) ceramic was prepared using conventional solid-state reaction and microwave sintering methods. Complex impedance spectroscopy (CIS) has been used to investigate the intra and intergranular contribution to the impedance SBN ceramics as a function of temperature and frequency. Complex impedance Cole?Cole plots were used to interpret the relaxation mechanism in SBN ceramic which showed a non-Debye relaxation. The grain and grain boundary contribution to conductivity have been estimated from the Cole?Cole plots. The bulk (grain) resistance of both samples was found to decrease with rise in temperature indicating negative temperature coefficient of resistance (NTCR) type behavior like that of semiconductors. The microwave sintered SBN was found to have low value of bulk resistance indicating more increase in conductivity as compared to conventionally sintered SBN. The temperature dependence of the relaxation time was found to obey the Arrhenius law. Studies of electrical modulus show the presence of hoping conduction mechanism in SBN.