Properties of praseodymium-doped bismuth potassium titanate (Bi0.5K0.5TiO3) synthesised using the soft combustion technique

Bismuth potassium titanate (Bi0.5K0.5TiO3; BKT) and praseodymium-doped BKT (Bi0.5(1-x)PrxK0.5TiO3; BPKT) powders were synthesised using the soft combustion technique. Fine particles of 10-100 nm of BKT and BPKT were produced. A single phase BKT was obtained with a minimum of 0.5 mol of glycine. Various compounds of Bi0.5(1-x)PrxK0.5TiO3 where x = 0.01, 0.03, 0.05, 0.10, 0.15 and 0.20 were prepared. Pure BKT and BPKT powders were obtained after calcination at 800 degrees C for 3 h. After sintering at 1050 degrees C for 5 h, pure BKT and BPKT pellets were obtained for x = 0 and 0.01. However, for BPKT with x = 0.03, 0.05, 0.10, 0.15 and 0.20, a minor amount of Bi4Ti3O12 (BIT) secondary phase was present after sintering at 1050 degrees C for 5 h. The crystallite size and grain size of all the samples followed similar trends, first increasing from x = 0 (undoped BKT) to x = 0.05 and then decreasing above x = 0.05. Among the undoped and doped samples, BPKT with x = 0.05 had the highest dielectric properties (epsilon(r) = 713.87) due to its large crystallite size (68.66 nm), large grain size (similar to 435 nm) and high relative density (93.39%). (C) 2010 Elsevier B.V. All rights reserved.