Abstract
The bismuth ferrites have attracted renewed interest in applications not only because BiFeO3, with high Curie temperature (TC = 1143 K) and Neel temperature (TN = 643 K), is a room temperature multiferroic material, but also because there is another phase, Bi2Fe4O9 with space group Pbam and Neel temperature TN ＝ 263 K, that has variety of applications including gas sensor, photocatalysts and catalysts. Through conventional hydrothermal synthetic route, we can obtain well-defined single crystallites of Bi2Fe4O9 and BiFeO3. The crystals obtained were characterized by the SEM (scanning electron microscope), XRD (X-ray diffraction), TEM (Transmission electron microscope) and VSM (Vibrating sample magnetometer) techniques. In addition, we were able to successfully synthesize a variety of morphologies of BiFeO3 and Bi2Fe4O9 by adding surfactant, oxidative anion, different ratios of precursor or K+/Na+, and by controlling the temperatures of suspension and mineralizer solutions. Controllable morphologies with facile hydrothermal methods are potentially useful in the aspect of variable magnetic, optical and electrical properties through development of various faces.