Dielectric relaxation and conduction mechanism studies of BNT-BT-BKT ceramics

摘要

AbstractElectrical properties of 0.884Bi0.5Na0.5TiO3-0.036BaTiO3-0.08Bi0.5K0.5TiO3ceramic samples were investigated in 100Hz to 1?MHz frequency range and in 200–450?°C temperature range using impedance spectroscopy technique. Real part of impedance versus frequency plots in lower frequency region revealed itsPTCRbehavior andNTCRbehaviors in higher frequency region. Impedance study also suggested the presence of non-Debye type relaxation mechanism. Cole-Cole plots suggested two relaxation regions, in which grain and grain, grain boundary effects were prominent in lower and high temperature regions, respectively. DC conductivity followed Arrhenius law with an activation energy of ～0.79 and 1.2?eV, which suggested that the charge carrier were cation vacancies in lower temperature region whereas cation vacancies and oxygen vacancies in higher temperature region.Highlights?PTCRandNTCRbehaviours in lower frequency region.?Only NTCR behaviour in higher frequency region.?Presence of non-Debye type relaxation mechanism.?Charge carriers were cation in lower temperature region.?Charge carriers were oxygen vacancies in higher temperature region.]]>