Structure, ferroelectric, magnetic, and energy storage performances of lead-free Bi4Ti2.75(FeNb)0.125O12 Aurivillius ceramic by doping Fe3+ ions extracted from Padang beach sand

• Published in: Case studies in chemical and environmental engineering 2024-06, Vol.9, p.100679, Article 100679
• Main Authors: Wendari, Tio Putra, Rizki, Alfir, Zulhadjri, Putri, Yulia Eka, Emriadi, Labanni, Arniati, Insani, Andon, Liandi, Agus Rimus
• Format: Article
• Language: English
• Subjects: Aurivillius phase; Dielectric properties; Energy storage performance; Iron sand; Multiferroic; γ-Fe2O3 phase
• ISSN: 2666-0164; 2666-0164
• DOI: 10.1016/j.cscee.2024.100679

This work successfully synthesized single-phase Aurivillius Bi4Ti2.75(FeNb)0.125O12 using a molten salt method and the natural precursor of Fe3+ ions extracted from Padang Beach sand. The study extensively examined the phase formation, crystal structure, grain morphology, and physical properties. X-ray diffraction (XRD) analysis combined with the Rietveld refinement technique confirms that Bi4Ti2.75(FeNb)0.125O12 adopts a B2cb orthorhombic structure. The refined atomic positions reveal that Bi3+ ions are located in the A-site within both the bismuth and perovskite layers, while the B-sites within the perovskite layers are primarily occupied by Ti4+/Nb5+/Fe3+ ions. The lower distortion of the inner B(1)O6 octahedra suggests the preference of Fe-rich clusters. The magnetization hysteresis suggests that the Bi4Ti2.75(FeNb)0.125O12 phase exhibits a weak antiferromagnetic state arising from the local short-range Fe–O–Fe antiferromagnetic ordering in the inner B(1)O6 octahedra. The electrical measurements reveal that the existence of ferroelectric ordering at room temperature comes from the structural distortion and the off-center ionic displacement. The energy storage capacity of 10.15 mJ/cm3 and efficiency (η) of 50.2% were obtained in ceramic sample under an electric field of 70 kV/cm at room temperature.