Atomistic Simulation of La and Mn-Doped Akram La Kilo, et al. 245 MOLEKUL eISSN: 2503- 0310 Articles https://doi.org/10.20884/1.jm.2022.17.2.6346 Atomistic Simulation of La and Mn-Doped PbBi2Nb2O9 Aurivillius Phase Akram La Kilo 1,2 *, Ramona Nintias R. Abas 1 , Alberto Costanzo 3 , Daniele Mazza 3 , Deasy N. Botutihe 1,2 , Jafar La Kilo 1,2 1 Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Gorontalo, Jl. Habibie, Desa Moutong, Kec. Tilongkabila, Bone Bolango Gorontalo, 96554, Indonesia 2 Department of Educational Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Gorontalo, Jl. Habibie, Desa Moutong, Kec. Tilongkabila, Bonebolango Gorontalo, 96554, Indonesia 3 Dipartimento di Scienza dei Materiali e’ Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy *Corresponding author email: akram@ung.ac.id Received November 09, 2020; Accepted March 15, 2022; Available online July 20, 2022 ABSTRACT. This study aims to determine the effect of Mn 3+ and La 3+ dopants on the structure of PbBi2Nb2O9 (PBN) using atomistic simulation. PBN phase geometry was optimized before the Mn 3+ and La 3+ -doped phase. Mn 3+ partially substituted octahedral Nb 5+ in the perovskite layer. While La 3+ partially substituted Bi 3+ in the bismuth layer and dodecahedral Pb 2+ in the perovskite layer. The concentration (x) of dopants that doped PBN was made in such a way that it produces a phase of Pb1-2xBi1.5 + 2xLa0.5Nb2-xMnxO9 (x = 0, 0.1, and 0.3) which was not charged. The simulation results showed that the optimized PBN cell parameters were in a good agreement with the experimental result. Increasing the concentration of dopants result in the Pb1-2xBi1.5+ 2xLa0.5Nb2-xMnxO9 phase (PBNM-Bi and PBNM-A) being less stable, as indicated by the increased lattice energy. PBNLM-Bi structures experiences an elongation which was showed by the cell parameters of c increase while a and b decrease. La 3+ prefers to occupy bismuth oxide layer rather than the dodecahedral A-site of the perovskite layer. The results of this simulation can explain the PBLNM structure of experimental results that do not pay attention to the multiplicity of doped PBN with certain dopant concentrations. Keywords: Atomistic simulation, Aurivillius, lanthanide dopants, manganese and PbBi2Nb2O9 INTRODUCTION Aurivillius is a layered bismuth oxide that has potential applications in ferroelectric random access memory, a catalyst in the petrochemical industry, and is used as a sensor (Prakash et al., 2007). This oxide also plays a role in fuel cells, especially as an electrolyte because of its high ionic conductivity. Solid electrolyte materials with high oxide conductivity at low temperatures are intensively investigated to obtain solid oxide fuel cell that is capable of operating at low temperatures (Kilo et al., 2011). Because of the potential application, the oxide is widely studied and synthesized. Aurivillius is a metal oxide compound consisting of a bismuth and perovskite layers with the general formula (Bi2O2) 2+ (An-1BnO3n+1) 2- (Aurivillius, 1949a, 1949b). Cation A is an ion with a charge of +1, +2, and 3 which has dodecahedral coordination. Cation A is in the form of alkali metal, earth alkaline, rare- earth elements, or mixtures thereof. Cation B which is smaller than cation A is a transition element that has octahedral coordination. The number of octahedral in the perovskite layer is shown by integer’s n with a value of 1≤n≤8. The electrical properties of Aurivillius can be improved by doping both the perovskite and the bismuth oxide layers. In the perovskite layer, the ions that can be substituted are in the A octahedral and dodecahedral sites. Meanwhile, Bi3+ substitution can only be done partially by certain metal ions so that the research results are still limited (Sadapu, 2015). Aurivillius compound that attracts attention is PbBi2Nb2O9 (PBN) because it has ferroelectric properties. PbBi2Nb2O9 has orthorhombic symmetry, A21am group space with a = b = 5,496, and c = 25.55 Å, where Pb 2+ occupies A site and Nb 5+ occupies B site. In the two-layer Aurivillius of PBN there is found a cation disorder between Pb 2+ and Bi 2+ in the perovskite layer at high level. That is because Pb 2+ and Bi 2+ both have lone pairs and this cation has the same tendency to occupy the perovskite and bismuth layers. Cationic disorder can affect the Aurivillius structure that is produced because the sizes of Pb 2+ and Bi 2+ are different (Ismunandar et al., 1996). The result is a small distortion in this PBN as a determinant of ferroelectric properties.