Structural, optical, dielectric and magnetic properties of Bi1‑xLaxFeO3 nanoparticles

In this work, the structural, optical, dielectric and magnetic properties of Bi_1‑xLa_xFeO₃ nanoparticles (x = 0.50 and 0.75) have been investigated at room temperature. Structural analysis indicated the coexistence of orthorhombic (Pbnm) and rhombohedral (R3c) phases. UV–visible absorption spectra of the samples exhibit two doubly degenerate d-d transitions and three charge transfer transitions. Using diffused reflectance UV–Vis spectra, the direct and indirect band gaps of the samples decreases with increasing La content. The dielectric constant (ɛ) of the samples in the microwave region exhibited an anomalous phenomenon at room temperature. Magnetic hysteresis loops (M‑H) of the samples exhibit weak ferromagnetism and an antiferromagnetic order. Additionally, the exchange bias effect was observed in these samples at room temperature. These results demonstrate that the method presented may be considered an effective way to improve the magnetic and optical properties of Bi_1‑xLa_xFeO₃.