Self-Assembled Bismuth Oxide Microrods Prepared by a Facile Chemical Method

Bismuth oxides (Bi2O3) are of interest because of their suitable band gaps for photocatalytic activity. Herein, a-Bi2O3 microrods were synthesized by a facile chemical method, and were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The results showed that the particles were rod-shaped with lengths in the range of 5-10 mm. Crystalline structure of the particles was monoclinic, and the band gap was around 2.88 eV.  When citric acid was used in the synthesis, the bismuth oxide microrods can self-assemble into the hierarchical flower-like structures leading to the alteration of band gap. This self-assembled a-Bi2O3 microstructure can be employed as a photocatalyst with alterable band gap

Synthesis of Patterned Media by Self-Assembly of FePt Nanoparticles

Patterned media is one of the most promising candidates for ultrahigh magnetic storage. Commonly, electron beam lithography is used to synthesize a very high areal density media beyond 1 Tb/in2. However, such techniques require very high budgets and are time consuming. Self-assembly of magnetic nanoparticles, especially FePt nanoparticles, has been realized as another prominent technique. Nevertheless in order to successfully exploit FePt nanoparticle self-assembly in patterned media fabrication, FePt nanoparticles of proper composition with the desired size and shape as well as a technique to control the assembled behavior of the particles in long range order are required. This review is focused on the chemical synthesis of FePt nanoparticles and how the particles self-assemble into regular arrays. Graphical abstrac

Magnetic Properties and Morphology Copper-Substituted Barium Hexaferrites from Sol-Gel Auto-Combustion Synthesis

The copper (Cu) substitution in barium hexaferrite (BaFe12O19) crystals from the sol-gel auto-combustion synthesis is demonstrated as a cost-effective pathway to achieve alterable magnetic properties. Subsequent heat treatments at 450 °C and 1050 °C result in irregularly shaped nanoparticles characterized as the M-type BaFe12O19 with the secondary phase of hematite (α-Fe2O3). Despite the mixed phase, the substantial coercivity of 2626 Oe and magnetization as high as 74.8 emu/g are obtained in this undoped ferrite. The copper (Cu) doing strongly affects morphology and magnetic properties of BaFe12−xCuxO19 (x = 0.1, 0.3, and 0.5). The majority of particles become microrods for x = 0.1 and microplates in the case of x = 0.3 and 0.5. The coercivity and magnetization tend to reduce as Cu2+ increasingly substitutes Fe3+. From these findings, magnetic properties for various applications in microwave absorbers, recording media, electrodes, and permanent magnets can be tailored by the partial substitution in hexaferrite crystals