E. A. Gudilin

Magnetic phase transitions in nanostructures with different cluster orderings

Nanostructures have been synthesized by (i) the micellar template method with the subsequent organization of Fe2O3 nanoclusters about 10 nm in size to a cluster crystal and (ii) by the aerosol method with the fixation of Fe2O3 nanoclusters about 10 nm in size in the NaCl matrix. The magnetic properties of the synthesized nanostructures have been studied. The Mössbauer spectroscopic examination of the cluster crystal revealed a magnetic phase transition of the first order, with the transition temperature being near the room temperature. This nanostructure is characterized by a steep magnetization curve, which is typical of an ordered structure with a weak intercluster interaction like a molecular crystal and a low energy of the magnetic anisotropy K = 3.5 × 104 J/m3. The disordered Fe2O3 nanostructure in the NaCl matrix is characterized by superparamagnetic behavior and smooth magnetization curves without saturation at 1 T and the magnetic anisotropy energy K = 2.5 × 104 J/m3, which is close to the corresponding value in bulk α- and γ-Fe2O3.

Immobilization of nanostructured metal silver at the surface of anodic titanium dioxide for the creation of composites with the surface plasmon resonance

X-ray-amorphous anodic titanium dioxide is proposed as a carrier of nanostructured silver with a controllable surface roughness for the creation of composite films with an effect of the surface plasmon resonance in the visible region for the spectroscopy of giant combinational scattering (GCS). A comparative analysis of GCS composites obtained by different methods of silver immobilization at the surface of a semiconductor TiO2 (photolysis of silver nitrate (I), magnetron sputtering, and thermal decomposition of ammonium silver complex (I)) has shown a substantial dependence of the functional characteristics on preparation history in the case of model analytes with different spectral characteristics, i.e., dyes of rhodamine 6G and methylene blue in low concentrations of 1 × 10−8 mol/L by an aliquot volume of less than 10 μL.

The local structure of TiO2-based nanotubes intercalated with iron (III)

Transmission electron microscopy, X-ray photoelectron spectroscopy, and 57Fe Mössbauer spectroscopy have been used to study TiO2-based nanotubes (TNTs) intercalated with 57Fe. A structural model of doped TNTs has been proposed that includes TNTs in the form of a “scroll” with nonmagnetic Fe-O-Fe layers spaced at ∼0.7-nm intervals in the interlayer spacing and ∼20-nm iron oxide clusters on the outer surface of the TNTs.

Lessons from the foreign nanohype

Based on an analysis of foreign experience, the origin and consequences of “hysterical” attitudes to nanotechnologies are considered. The historical and social aspects of nanotechnological evolution in Western countries and prospects for Russia are the focus of this paper.

Reduced graphite oxide decorated with gold nanoparticles for Raman scattering spectroscopy

Surface-enhanced Raman scattering (RS) spectroscopy is a sensitive analytical method that makes it possible to detect individual molecules. The substantial enhancement of the intensity of the signals in this method when compared to traditional Raman scattering is associated with two mechanisms, namely, electromagnetic and chemical. The first mechanism is associated with the enhancement of both the impinging and scattered radiation (electromagnetic enhancement), while the second mechanism is explained by the electron interaction between the molecule being analyzed and metal nanoparticles, namely, by the change in the polarizability of the adsorbed molecule, which results in the displacement and broadening of the electron levels of the adsorbed molecule or in the occurrence of new levels and promotes the enhancement of the signal in the Raman scattering spectrum. Graphene and material associated with it such as graphene oxide, graphite oxide, and reduced forms of graphene and graphite oxides are advanced materials for the creation of a significant chemical enhancement. Taking into account the different nature of the enhancement of the signal from the nanoparticles of noble metals and graphene and its derivatives, it is reasonable to study the effectiveness of hybrid structures on the basis of derivatives of graphene and noble metal nanoparticles in the Raman scattering spectroscopy of the analyte molecules with an aromatic structure.

The science Olympiad “Nanotechnology: Breakthrough into the Future”

The science Olympiad “Nanotechnology: Breakthrough into the Future,” a new educational program of the Moscow State University devoted to nanoscience, was described. The Olympiad combines the best traditions of Russian science Olympiads for schoolchildren with the new educational trends: research competitions for young scientists, creative contests for all participants, and a well-developed distant learning system. The Olympiad covers all the main branches of nanoscience and all the existing nanotechnologies. Examples of original problems on chemistry, physics, mathematics, and biology for schoolchildren were given. The new educational technologies used in the Olympiad, including distance learning techniques, were discussed. All the materials of the “Nanotechnology: Breakthrough into the Future” Olympiad are freely and openly available electronically.

Modern preparation methods of oriented thick films of superconducting cuprates

Modern trends in the development of methods of manufacturing biaxially textured large-grained coatings ∼ 100 μm thick based on superconducting rare-earth-barium cuprate elements, as well as bismuth-containing high-temperature superconductors, are considered. It is shown that the formation of a symmetric artificial surface relief makes it possible to control the mutual orientation of crystallites on polycrystalline metal substrates with high efficiency. In this case, the fraction of superconductor crystallites with an angle of mutual misorientation <5% may be as high as 75–90%. The high efficiency of this method of forming oriented films of multicomponent oxide phases indicates that it can be used to fabricate new-generation superconducting composite materials.