ABSTRACT

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 Sr₂Bi₄Ti_5-xFe_xO₁₈, Sr_2+0,5xBi₄Ti_5-xFe_xO₁₈, 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. Sr₂Bi₄Ti_5-xFe_xO₁₈, and Sr_2+0,5xBi₄Ti_5-xFe_xO₁₈ 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 Bi₂Mo_0.25W_0.75O₆, Bi_2+xLa_xTiNbO₉ (x = 0–1), ABi₂Ta₂O₉ (A = Sr, Ba, Ca), A_xSr_2-xBi₂Nb₂TiO₁₂ (A = Ba, Ca; and x = 0, 0.5), and Bi₅Ti_1.5W_1.5O₁₅, 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…)