Effect of cerium addition on the microstructure, electrical and relaxor behavior of Sr0.5Ba0.5Nb2O6 ceramics

Abstract

Sr0.5Ba0.5Nb2O6 (SBN50) ceramic doped with different concentrations of Cerium (Ce) according to the stoichiometry formulation of Sr0.5-3y/2Ba0.5CeyNb2O6 (Ce-SBN) with y = 0, 0.01, 0.02, 0.03, 0.04 and 0.05 was prepared using the conventional solid state reaction method. The morphology, structure, and electrical properties of the samples were studied using field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), ferroelectric and dielectric spectroscopy, respectively. The FESEM images reveal a strong influence of cerium on the SBN microstructure. The X-ray diffraction patterns show that all compositions of SBN ceramic exhibit tetragonal tungsten bronze structure. As the dopant concentration, y increased, both unit cell volume and axial ratio c/a decreased gradually. In addition, dopant incorporation lowers the phase transition temperature, Tm. As a result, all practical parameters are sufficiently increased, i.e. the dielectric constant and remnant polarization. SBN50 doped with a 3% Ce sample is most attractive for practical applications due to its high remnant polarization, Pr = 58.6 μC/cm2 and dielectric constant, ε’≈8000 (10 kHz) at room temperature, respectively.