Single-Step Fabrication of Au-Fe-BaTiO3 Nanocomposite Thin Films Embedded with Non-Equilibrium Au-Fe Alloyed Nanostructures

Directed Self-Assembly of Oxide Nanocomposites by Ion-Beam Lithography

Vertically aligned self-assembled nanocomposite films have provided a unique platform to study magnetoelectric effects and other forms of coupling between complex oxides. However, the distribution in the locations and sizes of the phase-separated nanostructures limits their utility. In this work, we demonstrate a process to template the locations of the self-assembled structure using ion lithography, which is effective for general insulating substrates. This process was used to produce a nanocomposite consisting of fin-shaped vertical nanostructures of ferroelectric BiFeO3 and ferrimagnetic CoFe2O4 with a feature size of 100 nm on (111)-oriented SrTiO3 substrates. Cross-sectional imaging of the three-phase perovskite-spinel-substrate epitaxial interface reveals the selective nucleation of CoFe2O4 in the trenches of the patterned substrate, and the magnetic domains of CoFe2O4 were manipulated by applying an external magnetic field.

Improvement of Photocatalytic Performance by Building Multiple Heterojunction Structures of Anatase-Rutile/BiOI Composite Fibers

In this study, multiple heterojunction structures of anatase-rutile/Bismuth oxyiodide (BiOI) composite fibers are designed by the combined method of electrospinning and hydrothermal techniques. The influence of different Ti/Bi atomic ratios ([Ti/Bi]) on the nanostructures and photocatalytic properties are investigated. It is found that the morphology of BiOI covered on the TiO₂ fiber surface changed with [Ti/Bi] from nanosheets to submicron spheres structures. Additionally, the crystallization of the composite fibers including the phases of anatase, rutile, and BiOI is identified, theses phases are in close contact with each other, and the interfacial effects are helpful to form the multiple heterojunctions which lead to blue shifts on the chemical state of Ti. The absorption of visible light has been improved by compositing BiOI on TiO₂, while the band gap values of the composite fibers are significantly reduced, which can enhance the generation and separation of electrons and holes. For the case of [Ti/Bi] = 1.57, the photodegradation rate of anatase-rutile/BiOI composite fibers is about 12 times that of pure TiO₂. For the photocatalytic mechanism, the synergistic s-type heterojunctions increase the content of active oxides which have a positive effect on the degradation rate.