Effect of strontium doping on structural and dielectric behaviour of barium titanate nanoceramics

Barium strontium titanate (Ba(1−x)SrxTiO3 where, x = 0.0, 0.2, 0.3, 0.4 and 0.5) nanoparticles have been successfully synthesised by sol–gel method and characterised thoroughly. With the increase in Sr concentration (x > 0.3), the symmetry of the crystal structure changed from tetragonal to cubic phase. The dielectric behaviour of the ceramic nanoparticles was evaluated using impedance analyser with an operating frequency of 1 Hz to 1 MHz. A very high dielectric constant 4915 was obtained for Ba0.7Sr0.3TiO3 at 1 Hz frequency with low dielectric loss of 1.91, which showed very good value than the one previously reported. The density of the material was found to be >98% of theoretical density. Dielectric constants were measured by varying the temperature from 35 to 150°C and the Curie temperatures were also evaluated. The small amount of Sr doping was beneficial for obtaining high dielectric constant material which can be used in various electronic applications.