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In this paper, we report the synthesis, phase formation, and basic characterization of polycrystalline Bi2Fe4O9, Bi1.98Ba0.02Fe4O9, and Bi1.98Ce0.02Fe4O9 samples prepared by the sol-gel technique. The crystal structure of the prepared samples has been characterized by means of X-ray diffraction and Raman scattering spectroscopy. All the obtained XRD peaks can be indexed to the orthorhombic Pbam structure and reveal the formation of Bi2Fe4O9. The Raman spectrum identifies Ag, B2g, and B3g active optical phonon modes. The crystallite size and morphology of the nanoparticles have been analyzed using scanning electron microscope (SEM). Dielectric constant (ε′) decreases as the frequency increases, and it is constant at the higher frequency region which can be explained based on the ionic conduction phenomenon in the low frequency region. The ε′ values of Bi2Fe4O9(650–850), Bi2Fe4O9(800–850), Bi1.98Ba0.02Fe4O9, and Bi1.98Ce0.02Fe4O9 samples at 10 Hz frequency are about 37, 75, 90, and 393, respectively. The observed properties signify that these materials are very useful in advanced technological and practical applications.

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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.

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