화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.98, No.10, 3291-3298, 2015
Local Structure Investigation in Multiferroic BiFeO3-BaTiO3 Ceramics by XAS Technique and Their Relevant Properties
The (1-x)BiFeO3-xBaTiO(3) (with x=0.1, 0.2, 0.3, and 0.4) ceramics were fabricated successfully by solid-state reaction method. Single-phase perovskite was obtained in all ceramics, as confirmed by XRD technique. It was observed that 0.7BiFeO(3)-0.3BaTiO(3) was the morphotropic phase boundary (MPB) between rhombohedral and cubic phases, as also revealed from ferroelectric and magnetic properties. The simulated and experimental X-Ray Absorption Spectroscopy (XAS) study revealed that BT in 0.75BF-0.25BT is possibly taken a rhombohedral structure. Furthermore, the rounded ferroelectric hysteresis loops observed for 0.9BiFeO(3)-0.1BaTiO(3) and 0.8BiFeO(3)-0.2BaTiO(3) compositions could be attributed to their microstructure and surface charge effects and electron transfer between Fe3+ and Fe2+ ions. It was also found that high dielectric constant of 0.9BiFeO(3)-0.1BaTiO(3) composition was a result of grain and grain-boundary effects, as observed in SEM micrographs. In addition, a strong signature of dielectric relaxation behavior was observed in this ceramic system with the activation energy 0.467eV obtained from the Arrhenius' law. Finally, the local structure investigation with XAS technique provided additional information to better understand the electric and magnetic properties in the BF-BT ceramic system.