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 °C for 3 h. After sintering at 1050 °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 °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 (ɛr = 713.87) due to its large crystallite size (68.66 nm), large grain size (∼435 nm) and high relative density (93.39%).

Research highlights▶ This work shows synthesis and characterization of praseodymium-doped bismuth potassium titanate (Bi0.5K0.5TiO3; BKT) using the soft combustion technique. Fine particles of 10–100 nm of BKT and BPKT were produced. Pure BKT phase can be obtained by adding glycine to aid in combustion process after calcination at 800 °C for 3 h. The doping of Pr in BKT structure results in improving dielectric properties of up to x = 0.05, and then decreasing above x = 0.05. Among these undoped and doped samples, BPKT with x = 0.05 has the highest dielectric properties (ɛr = 713.87) due to its large crystallite size (68.66 nm), large grain size (∼435 nm) and high relative density (93.39%). To the authors’ knowledge, there is no publication on synthesis of this compound using this approach.