Synthesis,characterisation and dielectric properties of low-loss Zr-doped barium strontium titanate materials

A series of materials of the composition Ba_0.7Sr_0.3Zr _x Ti_{(1 − x)}O₃ (BSZT), where x = 0.00, 0.01, 0.02 and 0.03, were synthesised through the sol–gel method whereupon the manifestations of partial substitution of Ti⁴⁺ by Zr⁴⁺ on the structural and dielectric behaviour of Ba_0.7Sr_0.3TiO₃ (BST) were studied. X-ray diffraction patterns of all samples showed the development of a single-phase crystalline perovskite structure. The dielectric behaviour of the ceramic samples has been studied in detail in the frequency range 10 Hz to 1 MHz at room temperature, and as a function of increase in temperature. The sample with 2% Zr recorded the highest dielectric constant. The dielectric loss values for all the BSZT compositions are remarkably low, tan δ = 0.021∼0.026 at 1 MHz, in contrast to the literature reports. It is observed that small amount of Zr doping on BST, where 0 < x ≤ 0.03 results in the enhancement of dielectric constant while decreasing the bulk density and dielectric loss.