Effect of barium doping on electrical and electromechanical properties of (1-x)(Na0.5Bi0.5)TiO3-xBaTiO3

Abstract

<p>The effect of Barium doping is studied on ferroelectric properties of (1-x)(Na<sub>0.5</sub>Bi<sub>0</sub>.<sub>5</sub>)TiO<sub>3</sub>-xBaTiO<sub>3</sub> with( x = 0.00; 0.0 3; 0.05; 0.06; 0.07; 0.08 and 0.10) prepared through solid state sintering route. X-ray diffraction along with Rietveld refinement revealed a gradual change in crystal structure from rhombohedral to tetragonal with increasing BaTiO3 doping in the compound. SEM images have shown a uniform distribution of grains and change in grain size with BaTiO<sub>3</sub> concentration. Dielectric and dispersive studies have been carried out. The rhombohedral distortion of the unit cell slightly increased and ferroelectric transition temperature, T<sub>m</sub> decreased with the increase of Barium content and all compositions of (1-x)(Na<sub>0.5</sub>Bi<sub>0</sub>.<sub>5</sub>)TiO<sub>3</sub>-xBaTiO<sub>3</sub>ceramic materials reveal diffuse phase transition that is marked by a strong frequency dispersion of the permittivity which would be related with the cation disorder in the A site of the unit cell. Combined impedance and electrical propriety were used to analyze impedance data. The electromechanical parameters were calculated from the resonant and anti-resonant frequencies from the evolution of the permittivity according to the frequency plots. The electromechanical coefficients for (1-x)(Na<sub>0.5</sub>Bi<sub>0</sub>.<sub>5</sub>)TiO<sub>3</sub>-xBaTiO<sub>3</sub>with all compositions were found to be much larger than that of pure Na<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3.</sub></p>