Dielectric relaxation and electrical properties of Na_0.5Bi₄La_0.5Ti₄O₁₅ electroceramics

Aurivillius single-phase Na_0.5Bi₄La_0.5Ti₄O₁₅ ceramics was prepared via solid state mixed oxide sintering technique. The ac data in terms of dielectric and impedance were collected to investigate the electrical properties and dielectric relaxation behaviors in the ceramics. The detailed frequency spectrum analysis demonstrates the existence of single dielectric relaxation behavior in the material, which is due to the grains contribution. A phase transition was observed to take place at ~570 °C. Ar-annealing study showed that above ∼280 °C, relaxation and conduction of the ceramics was assigned to the motion of ionized oxygen vacancies. The kinetic analysis was performed to probe the conduction-relaxation mechanisms in the ceramics. The present results could be significant for deep understanding of electrical properties and defect-relaxation behaviors in Na_0.5Bi₄La_0.5Ti₄O₁₅ related ceramics.