Dielectric relaxation and conduction behaviors of Aurivillius Na _0.5 Bi _4.5 Ti ₄ O ₁₅ ceramics with Na doping

Abstract

Abstract Aurivillius Na 0.5 Bi 4.5 Ti 4 O 15 and Bi 4 Ti 3 O 12 compounds were synthesized via solid‐state reaction technique. X‐ray powder diffraction study confirmed monophasic four‐layered Na 0.5 Bi 4.5 Ti 4 O 15 and three‐layered Bi 4 Ti 3 O 12 ceramics. Dielectric relaxation and conduction behaviors of Na‐contained Na 0.5 Bi 4.5 Ti 4 O 15 ceramics were thoroughly investigated in a large scale of temperature of 30–650 °C and frequency of 40 Hz–1 MHz. In addition, comparative studies of both the compounds were discussed. Impedance and modulus analyses revealed a single relaxation behavior in Na 0.5 Bi 4.5 Ti 4 O 15 compound which was originated from the grain's interior with grain resistance of 2.189 × 10 5 Ω and capacitance of 4.268 × 10 −10 F at 570 °C. While in Bi 4 Ti 3 O 12 ceramic the relaxation was due to the contributions of grain and grain boundaries. Alternating current (AC) conductivity analysis revealed the presence of two different conduction regions in both the compounds. Activation energies for the two different conduction mechanisms, i.e., in low‐temperature region and in high‐temperature region were calculated to be ~ 0.23 and ~ 1.27 eV at 1 kHz for Na 0.5 Bi 4.5 Ti 4 O 15 compound and ~ 0.43 eV and ~ 0.97 eV at 1 kHz for Bi 4 Ti 3 O 12 compound, respectively. The present study of dielectric relaxation and conduction behaviors would be helpful for further investigations of Na 0.5 Bi 4.5 Ti 4 O 15 ‐related Aurivillius compounds.