Synthesis and characterization of submicron single-crystalline Bi ₂Fe₄O₉ cubes

Single-crystalline, submicron-sized Bi₂Fe₄O ₉ cubes of reproducible shape have been successfully prepared using a facile, large-scale solid-state reaction employing a molten salt technique in the presence of a nonionic surfactant. The role of surfactant as well as alterations in the molar ratio of Bi³⁺ to Fe³⁺ precursors have been examined under otherwise identical reaction conditions and correlated with the predictive formation of different shapes of Bi₂Fe ₄O₉ products. Extensive structural characterization of as-prepared samples has been performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive X-ray spectroscopy (EDS), selected area electron diffraction (SAED), Mössbauer spectroscopy, and X-ray diffraction (XRD). Magnetic measurements were obtained using a superconducting quantum interference device (SQUID).