Ferroelectric and relaxor Behavior of Fe-Doped Sr0.5Ba0.5Nb2-xFexO6 ceramics with a tungsten-bronze structure

Fe doped Sr0.5Ba0.5Nb2O6(SBNF) ceramics were prepared by using a solid state reaction method. X-ray diffraction showed a SBNF single phase with a tungsten-bronze structure. The relaxor behaviors related to the dielectric and the ferroelectric properties were investigated. With increasing Fe contents, the phase transition temperature decreased and the dielectric constant peak broadened. Ferroelectric P-E hysteresis loops exist above the phase transition temperature. With increasing measured frequency, the dielectric-constant maximum peak shifts toward higher temperature, which indicates a relaxor behavior. The correlation between the measured frequency and the maximum temperature of dielectric peak is explained by using the Vogel-Fulcher model. The effects of Fe doping on the dielectric, the ferroelectric and the relaxor behaviors of SBNF ceramics were investigated.