Bi-substituted barium lanthanum titanates with the general formula Ba4(La(1-z)Biz)(9.33)Ti18O54 where z = 0.0 to 0.2 in steps of 0.05 were synthesized by a conventional mixed oxide route. The composition and morphology were determined using scanning electron microscopy (SEM) and X-ray powder diffraction analysis (XRD). Two dielectric performance parameters, namely dielectric constant and loss tangent were measured with varying microwave frequency in the range 0.3 to 3 GHz at room temperature. It was observed that the dielectric constant and loss tangent both increased initially for z <= 0.10 and then decreased. The best properties were obtained for z = 0.20 with a dielectric constant of 91.4 and loss tangent of 0.004. This could be a promising microwave material with a high dielectric constant and low loss.

Keywords: ceramics; X-ray Diffraction; scanning electron microscopy; dielectric constant; loss tangent