Electrical responses of Pb₂Sb₃RTi₅O₁₈ (R  La, Nd, Sm, Gd, Dy) ceramics

Abstract

Single-phase orthorhombic tungsten bronze ceramics of Pb₂Sb₃RTi₅O₁₈ (R  La, Nd, Sm, Gd, Dy) are prepared via high temperature solid-state reaction method. The values of cell parameters phase transition temperature and activation energy are found to depend on rare earth ion content. These materials have low dielectric constant, low loss and high resistivity. The samples showed dielectric relaxation which are found to be of non Debye type. The nature of variation of resistivity with temperature and Nyquist plots suggested the NTCR character. The ac conductivity is found to obey the universal power law and supports the correlated barrier hopping of the carriers as conduction mechanism.