Month: February 2007


Synthesis and Atomic Simulation of Aurivillius Oxides

Most of studies in Aurivillius oxide have been synthesized of Aurivillius oxides with d0 cation as B cation. Recently, attempts to substitute d0 with dn cation at perovskite layered has been started. In this work attempt to substitute (Ti4+) with (Fe3+) has been carried out. Aurivillius oxides Sr2Bi4Ti5-xFexO18, Sr2+0,5xBi4Ti5-xFexO18, Pb2Bi5Ti5FeO21 and Pb3Bi5Ti6FeO24 have been synthesized using the solid state reaction method. X-ray Diffraction powder data were refined using Le Bail method implemented in Rietica. Sr2Bi4Ti5-xFexO18, and Sr2+0,5xBi4Ti5-xFexO18 oxideshave space group B2cb, Z = 4; whilst Pb2Bi5Ti5FeO21 and Pb3Bi5Ti6FeO24oxideshave space group A21am, Z = 4 and I4/mmm, Z = 2.The random substitution of cation Fe3+ at Ti4+ position in these Aurivillius oxides was showed by the increase of lattice volume and magnetic moment in these oxides with increasing Fe substitution. The results of atomic simulation indicate that there were goal agreements between the simulated and experimental structural parameter for several Aurivillius oxides like Bi2Mo0.25W0.75O6, Bi2+xLaxTiNbO9 (x = 0–1), ABi2Ta2O9 (A = Sr, Ba, Ca), AxSr2-xBi2Nb2TiO12 (A = Ba, Ca; and x = 0, 0.5), and Bi5Ti1.5W1.5O15, with the differences less than 0.03 %. Yoder Flora equation can be used to determine lattice energy of Aurivillius oxides.

Keywords: Aurivillius oxides; Solid state reaction; Le Bail method; Magnetic moment, Atomic Simulation. (more…)