Synthesis and magnetic property of submicron Bi₂Fe₄O₉

Uniform submicron Bi₂Fe₄O₉ samples were successfully prepared at low temperature via a facile, one-step hydrothermal synthetic route. Fe(NO₃)₃ and Bi(NO₃)₃ were used as iron and bismuth sources; NaOH was used as pH adjustor and mineralizer. The morphologies of the products can be readily controlled by reaction conditions, such as NaOH concentration in the precursor solution and reaction temperature. The as-prepared samples were characterized with scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, and X-ray diffraction. Magnetic measurements indicated a spin antiferromagnetic ordering at low temperature and a Néel magnetic transition at 260 K.