High-Temperature Dielectric Relaxation and Electric Conduction Mechanisms in a LaCoO3-Modified Na0.5Bi0.5TiO3 System

This research study examines the high-temperature dielectricrelaxationand electric conduction mechanisms in (x)LaCoO3-(1 - x)Na0.5Bi0.5TiO3 samples, where x is 0.05, 0.10,and 0.15. The findings demonstrate that all the samples exhibit twodielectric transitions: first, a frequency-dispersive shoulder ata lower temperature (T (s)) around 425-450K, which is associated with polar nanoregions (PNRs), and second,from ferroelectric to paraelectric transition at the Curie temperature(T (c)) approximately between 580 and 650K. The impedance analysis reveals the negative temperature coefficientof resistance behavior of the specimens. The broad and asymmetricrelaxation peaks obtained from modulus spectroscopy demonstrate awide range of relaxations, suggesting non-Debye-type behavior. Furthermore,the conductivity studies provide insights into understanding the transportphenomena in the samples. The oxygen vacancies resulting from theaddition of LaCoO3 into the Na0.5Bi0.5TiO3 ceramics are responsible for the relaxation and conductionprocesses, and the charge carrier is doubly ionized oxygen ion vacancies.All samples except for LCNBT10 at 1 kHz exhibit a negative magnetodielectricresponse.