Dielectric and ferroelectric properties of Ba3M3Ti5Nb5O30 (M = Sm or Y) ceramics

Ba3M3Ti5Nb5O30 (M=Sm or Y) compounds were synthesized by the conventional powder compaction and high temperature solid state reaction technique. The calcined compounds were pelletized and sintered in the range 1275-1325 degreesC for 4 h. The dielectric and ferroelectric properties of the sintered pellets were measured and further characterised by X-ray diffraction and scanning electron microscopy (SEM). Sm and Y substituted compounds were found to have tetragonal structure and shown dielectric constants of 145 and 49 respectively at 1 MHz. The dielectric loss increases with frequency. Samarium compound had undergone a diffuse phase transition in the temperature range 195-210 degreesC whereas the same with Yttrium had shown the transition at around 25 degreesC. (C) 2001 Kluwer Academic Publishers.