Structural, ferromagnetic and optical properties of pure bismuth A-site polar perovskite Bi(Mg_3/8Fe_2/8Ti_3/8)O₃ synthesized at ambient pressure

Bi(Mg_3/8Fe_2/8Ti_3/8)O₃ (BMFT) perovskite oxide ceramic has been synthesized by a conventional solid-state reaction method at ambient pressure. Structural characterization is detected by X-ray diffraction (XRD) and Raman spectroscopy, reflecting a polycrystalline perovskite structure. The peaks in XRD pattern shift toward lower angle, which indicates larger lattice constant than BiFeO₃ (BFO). High frequency modes blue shift and the peak broadening can be observed clearly in micro-Raman spectroscopy compared with BFO patterns. Morphology analysis through scanning tunneling microscope shows dense and well-interlinked grains. Through the UV–Vis–NIR spectra, BMFT displays a narrow band gap of 2.23 eV, smaller than the 2.8 eV band gap of BFO. The room-temperature ferromagnetism of BMFT ceramic is measured for the first time, which can be attributed to the nonmagnetic ions of Mg²⁺ and Ti⁴⁺ ions replacing Fe³⁺ ions that causing the remanent magnetic moments. These results will open an avenue to further design multiferroic data storage and photovoltaic devices.