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.



Studi yang banyak dilakukan pada oksida Aurivillius adalah sintesis oksida Aurivillius dengan menggunakan kation d0 pada posisi B. Saat ini dikembangkan usaha sintesis oksida Aurivillius dengan substitusi kation dn pada kation d0. Penelitian ini untuk mensubstitusi kation dn (Fe3+) pada posisi d0 (Ti4+). Oksida Aurivillius yang telah disintesis dengan menggunakan metode reaksi kimia padat adalah Sr2Bi4Ti5-xFexO18, Sr2+0,5xBi4Ti5-xFexO18, Pb2Bi5Ti5FeO21 dan Pb3Bi5Ti6FeO24. Data difraksi sinar-X serbuk dianalisis menggunakan metode Le Bail pada program Rietica. Oksida Sr2Bi4Ti5-xFexO18 dan Sr2+0,5xBi4Ti5-xFexO18 memiliki grup ruang B2cb, Z = 4, sedangkan Pb2Bi5Ti5FeO21 dan Pb3Bi5Ti6FeO24 memiliki grup ruang A21am, Z = 4 dan I4/mmm, Z = 2. Substitusi secara acak kation Fe3+ pada posisi Ti4+ pada oksida Sr2Bi4Ti5-xFexO18 dan Sr2+0,5xBi4Ti5-xFexO18 didukung dengan terjadinya peningkatan volume sel dan momen magnet oksida ini dengan meningkatnya substitusi kation Fe. Hasil simulasi pada beberapa oksida Aurivillius seperti: Bi2Mo0,25W0,75O6; Bi2+xLaxTiNbO9 (x = 0–1), ABi2Ta2O9 (A = Sr, Ba, Ca); Bi2-xSr2+xNb2TiO12 (x = 0; 0,2); AxSr2-xBi2Nb2TiO12 (A = Ba, Ca; dan x = 0; 0,5); dan Bi5Ti1,5W1,5O15 menunjukkan bahwa terdapat kecocokan antara simulasi dan data studi difraksi sinar-X dengan perbedaan sebesar 0,03%. Persamaan Yoder Flora dapat digunakan untuk menghitung energi kisi oksida Aurivillius.

Kata kunci: Oksida Aurivillius; Reaksi kimia padat; Metode Le Bail; Momen magnet, Simulasi atomik.