Structural, Electrical, and Magnetic Properties of Mullite-Type Ceramic: Bi2Fe4O9

Abstract

This work reports the structure, electrical and magnetic properties of the orthorhombic (Pbam) structured bulk Bi2Fe4O9 synthesized by the solid-state reaction process. Bi2Fe4O9 has been studied using several experimental techniques such as X-ray diffraction, scanning electron microscopy, Raman spectroscopy, dielectric spectroscopy, and magnetometry. Rietveld-refined X-ray diffraction data and Raman spectroscopy results clearly reveal the formation of Bi2Fe4O9 perovskite structure and all the peaks of Bi2Fe4O9 perfectly indexed in the orthorhombic (Pbam) structure. It has been established that the Raman spectrum identified Ag, B2g, and B3g active optical phonon modes, and that the Raman peak at 470 cm−1 may have a magnetic origin. As a result, the coexistence of weak ferromagnetic and antiferromagnetic orders in Bi2Fe4O9 ceramic was established. The remanent magnetization (2Mr) and coercivity (2Hc) are 8.74 × 10−4 emu/g and 478.8 Oe, respectively. We report a remarkable multiferroic effects in polycrystalline Bi2Fe4O9 ceramic. These characteristics make this material very useful in technology and practical applications.