Yu. S. Tver’yanovich

Ion-conducting multilayer films based on alternating nanolayers Ag 3 SI, AgI and Ag 2 S, AgI

Multilayer films of two types, namely, films with alternating nanolayers Ag2S and AgI and alternating nanolayers Ag3SI and AgI, are prepared by laser ablation. The conductivity of the film samples is investigated using impedance spectroscopy. The ends of fractures of the multilayer films are examined with electron microscopy.

Side reactions during laser-induced deposition of copper from aqueous solutions of CuII complexes

The composition of the gas phase formed during laser-induced chemical liquid phase deposition (LCLD) of copper was studied. Based on the results of a mass spectrometric study of the gases, 1H NMR spectra of the autocatalytic solutions, EDX spectra of the copper deposit, and the dielectric substrate, side reactions of organic components of the solutions at the laser beam focusing point were suggested.

Laser-Induced Copper Deposition on the Surface of an Oxide Glass from an Electrolyte Solution

Continuous copper patterns were grown on the surface of oxide glass substrates through laserinduced chemical liquid-phase deposition (LCLD). The deposition was performed with the use of a continuouswave argon laser operating in a multimode regime. The deposition occurred as a result of the reducing chemical reaction initiated by laser radiation. Continuous metal patterns were produced by scanning focused laser radiation along the substrate-electrolyte interface. The morphology and the chemical composition of the deposited patterns were examined with the use of a CEM-SCAN 4 DV scanning electron microscope equipped with an energy-dispersive spectrometer. The morphology of the deposited patterns was investigated as a function of the laser radiation power and the number of scans. It was demonstrated that high-quality continuous patterns can be fabricated using one scan of the laser beam.

Mechanical modification of β-AgI nanocrystals

A nanostructured AgI powder has been synthesized. The structure, sizes, and shapes of nanoparticles of the initial powder and a powder modified in a VIBRATOR GM-945B vibration ball mill have been investigated by SEM, X-ray diffraction, and differential thermal analysis. A hypothesis of the structure and microscopic mechanism of structural transformations in the materials under study is proposed. Particular attention is paid to the ac ionic conduction of silver iodide particles.

Preparation and properties of CuCr2Se4 ferromagnetic spinel nanocrystals

Polycrystalline and nanocrystalline samples of the CuCr2Se4 ferromagnetic spinel are synthesized. The mean size of nanocrystals is 50 nm. The Curie temperature of spinel nanocrystals (465 K) is higher than that of spinel polycrystals (435 K). Laser irradiation at a wavelength of 1.5 μm (in an external magnetic field) increases the magnetization of the noncrystalline powder. Most likely, this can be explained by the change in the orientation of magnetic moments of single-domain nanoparticles. The observed effect reaches a maximum in magnetic fields with a strength lower than that of the saturation field.

Ionic conductivity of (As2Se3)1 − x(AgHal)x (Hal = I, Br) nanocomposites

Nanocomposites based on chalcogenide glasses have been synthesized. A differential thermal analysis of (As2Se3)1 − x(AgI)x and (As2Se3)1 − x(AgBr)x (0 ≤ x ≤ 0.5) samples has been performed. The size of nanofragments that undergo elementary structural transformations has been evaluated. The data obtained are in agreement with the evaluated sizes of X-ray coherent scattering regions. The electrical properties of the glasses under consideration have been studied using impedance spectroscopy in the temperature range 293–393 K. It has been demonstrated that the ionic component of the electrical conductivity dominates in glasses with a high content of silver halide.

Non-radiative energy transfer from Er3+ ions to the electronic states of the chalcogenide glass matrix

Lifetime spectroscopy of the chalcogenide systems Ga-Ge-S:Er 3+ and Ga-Ge-S-Se:Er 3+ has shown that the non-radiative energy transfer from rare-earth ions to the electronic states of the chalcogenide matrix is important. Numerical calculations of transition probabilities (W R , W mph , W CR ) allowed estimation of the probability of the energy transfer to the chalcogenide matrix. It was found that when the optical bandgap of the matrix approaches the Er 3+ level, the probability of such energy transfer process will increase as long as a complete resonance is not achieved.

On the Variation of the Structure of Nanocomposite Solid Electrolytes

Nanostructured media involving channels that provide ion transfer are considered. It is shown that the ionic conductivity can be significantly increased by varying the configuration of these channels and their potential profile. Special attention is focused on nonuniform media in which the channels are nonuniformly distributed in the bulk of the sample.

Preparation and investigation of 0.7AgI · 0.3ZnO nanocomposite films

Films of the binary compound AgI and the two-phase composite 0.7AgI · 0.3ZnO have been produced using laser ablation. The temperature dependences of the electrical resistivity of samples prepared in the form of AgI pellets pressed from a fine-grained powder and samples in the form of films of the AgI compound and the 0.7AgI · 0.3ZnO two-phase composite have been investigated using impedance spectroscopy. The sizes of particles in all the samples studied have been estimated by the Scherrer method. It has been shown that zinc oxide in the 0.7AgI · 0.3ZnO two-phase composite can play the role of an dispersing agent for AgI crystallites. The phase compositions of the initial materials and films, as well as the degree of stress of crystals in all the samples under investigation, have been examined using X-ray diffraction analysis. It has been demonstrated that diffraction reflections from 0.7AgI · 0.3ZnO two-phase composite films are shifted toward shorter interplanar distances as compared to the reflections from the other samples, which indicates the presence of mechanical stresses in this composite.

Decomposition of pentaammineaquacobalt(III) perchlorate under laser radiation action

Photolytic decomposition of the complex [Co(NH3)5(H2O)](ClO4)3 under the action of a laser with a wavelength of 355 nm, which is resonant in energy to the energy of the (1A1g → 1T2g) d–d transition, was studied. Decomposition of the complex is accompanied by a release of ammonia with its subsequent oxidation to nitrogen oxides and by partial cobalt reduction with the formation of the mixed cobalt(II, III) oxide Co3O4.