SYNTHESIS OF SINGLE-PHASE BISMUTH FERRITE USING SOL-GEL AUTOCOMBUSTION METHOD AND ITS MAGNETIC AND DIELECTRIC PROPERTIES

• Main Author: Rafitasari, Yeti
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57456
• Institution: Institut Teknologi Bandung

Bismuth ferrite (BiFeO3/BFO) is a multiferroic material that has attracted the attention of researchers because it has ferroelectric and antiferromagnetic properties at room temperature and its wide potential applications. Synthesis of single-phase BFO hard to obtain because of the narrow stability temperature range, so it is always followed by the secondary phase Bi25FeO39 dan Bi2Fe4O9. In this study, BFO powder was synthesized using the sol-gel autocombustion method from precursors such as bismuth and iron nitrate with stoichiometric variations between Bi and Fe, namely the excess of 2% Fe, 1:1, and excess of 3% Bi. In addition to stoichiometric variations, variations in the sintering temperature and variations in the type of cooling were also carried out. Single-phase BFO with an atomic ratio of Bi:Fe= 1:1 was obtained when excess of 3% Bi which was sintered at a temperature of 550? for 2 hours and followed by a quenched process which was then labeled Bi 3% (550Q2,1). Sample Bi 3% (550Q2.1) showed a weak ferromagnetic hysteresis curve with remanent magnetization and coercive fields of 0.0412 emu/g and 691.71 Oe at room temperature, respectively. The results of dielectric measurements show that the real dielectric constant (?') produces a downward trend with increasing frequency due to the Maxwell-Wagner relaxation, and an increasing trend with increasing temperature due to having sufficient thermal activation energy. The relationship between magnetic properties and electrical properties of BFO samples can be explained through local octahedral distortion, FeO6 tilt angle, Fe-O-Fe bond angle, Fe-O bond length, and Bi-O bond length obtained from rietveld refinement analysis using GSAS 2.