Mingzai Wu

Hydrothermal synthesis and characterization of Bi 2 Fe 4 O 9 nanoparticles

Sheet-like Bi2Fe4O9 nanoparticles were successfully synthesized by a rather facile hydrothermal process. Transmission electron microscopic (TEM) and selected area electron diffraction (SAED) studie...

ROOM TEMPERATURE SELF-ASSEMBLY GROWTH OF COBALT NANOWIRES UNDER MAGNETIC FIELDS

Polycrystalline cobalt nanowires, with average diameter of 80 nm and length about 10 μm, were synthesized in the hydrazine hydrate solution at room temperature under magnetic fields. A seed-mediated growth approach was applied. Magnetic fields induced the growth of nanowires via aligned self-assembly of cobalt nanocrystallites. Magnetic measurements showed that the saturation magnetization (Ms) of the cobalt nanowires synthesized under magnetic field was five times larger than that of the samples prepared without magnetic fields; while the coercivity (Hc) of the sample prepared under magnetic fields was half of that of the sample synthesized without magnetic fields. The reasons for the magnetism changes were discussed.

IMPROVEMENT OF COERCIVITY IN COBALT-DOPED ANATASE TiO2 NANOPARTICLES HYDROTHERMALLY PREPARED

Anatase Ti1-xCoxO2 nanoparticles were prepared by a hydrothermal process at 180 °C. Ferromagnetic hysteresis loops of the as-prepared samples were measured at room temperature. The Ti1-xCoxO2 (x = 0.0376) powder shows coercivity up to 700 Oe, which is the highest value reported for anatase Ti1-xCoxO2. X-ray diffraction (XRD), transmission electron microscopy (TEM) and magnetic measurement results provided evidence that Co was incorporated into TiO2 lattice. Combined with the fact that the preparation was carried out in an oxidized environment starting from cobalt (II) in the oxidized state, it is suggested that the homogeneous doping of Co into the lattice of anatase should be responsible for the improvement of coercivity in anatase Ti1-xCoxO2 nanoparticles.

Hydrothermal Synthesis and Characterization of Bi2Fe4O9Nanoparticles

Sheet-like Bi2Fe4O9 nanoparticles were successfully synthesized by a rather facile hydrothermal process. Transmission electron microscopic (TEM) and selected area electron diffraction (SAED) studie...