The structural and electrical properties of SrxBa(1−x)Nb2O6 (SBN) ceramic with varied composition

Abstract

Strontium barium niobate (SBN) with the stoichiometric formula of SrxBa(1−x)Nb2O6 was synthesized using the solid-state reaction method. The compositions were varied as x=0.25, 0.30, 0.50, 0.51, 0.53, 0.55, 0.57 and 0.60 to identify the composition with the optimum structural and electrical properties. The structural properties of the SBN ceramic were studied using X-ray diffraction spectra, while the morphology of the sintered grain was monitored by a field emission scanning electron microscope (FESEM) measurement. The dielectric behavior and the main features of the diffuse phase transition of the SBN ceramics with relaxor behavior were carefully investigated. The increment of the x composition gives rise to continuous decrease of the temperature of the maximum dielectric constant. The effect of the diffuse phase transition and relaxation feature of the SBN can be attributed to the Sr2+ (variation of x composition) site distribution. The SBN ceramic with composition x=0.53 showed a saturated hysteresis loop at an applied field of 50kV/cm, showing the highest remnant polarization of 8.17μC/cm2 with a coercive field of ~11kV/cm. The leakage current densities of the SBN samples were ranged between 0.1 and 1×10−5A/m2 over a voltage range from 100V to 6kV. From these findings, the composition of x=0.53 gives the best electrical and structural properties compared to the rest of the compositions investigated and has potential application for practical lead free ferroelectric sensors.