Dielectric and ferroelectric behavior of SBN50 synthesized by solid-state route using different precursors

In the present study, two different sets of precursors have been used in the synthesis of strontium barium niobate (SBN50) by conventional solid-state route: I. Sr(NO3)2, Ba(NO3)2, Nb2O5 and II. SrCO3, BaCO3 and Nb2O5. The formation of SBN50 phase was completed at 1150 °C. The green compacts, of the calcined powder, were sintered at temperatures varying from 1250 to 1350 °C. Microstructural characterization was done using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The aim was to study the dielectric and ferroelectric behavior depending on the precursors used and the sintering conditions and correlate with microstructure. The synthesis, involving the precursor set-I, showed a duplex microstructure with large number of small grains, of size 10–15 μm, sandwiched between very large grains, of size in the range of 50–200 μm. On the other hand the second set of precursor resulted in a microstructure devoid of duplex nature. The microstructure consisted of polyhedral grains having more or less uniform size. SBN from set-II showed a better dielectric property compared to set-I. The discrepancies in this ferroelectric/dielectric behavior, have been explained in terms of density as well as microstructural differences.