Size effect in (Sr/sub x/Ba/sub 1-x/)Nb/sub 2/O/sub 6/ ultrafine powder

The sol-gel derived (Sr/sub x/Ba/sub 1-x/)Nb/sub 2/O/sub 6/ (SBN) ultrafine powder can be obtained at an annealing temperature as low as 700/spl deg/C, which is 500/spl deg/C lower than that previously reported. The powder has a well crystallized pure perovskite structure and its average crystallite size is about decades of nm. The specific heat has a broadened peak, and the transition temperature from the ferroelectric to the paraelectric phase is clearly lower than that of SBN bulk material. This new phenomenon can be ascribed to the size effect.