K.E. Prikhodko

The Effect of Radiation-Induced Structural Changes under Accelerated Irradiation on the Behavior of Water-Cooled Reactor Pressure Vessel Steels

In this paper the influence of fast neutron flux on the structural features and properties of VVER-1000 reactor pressure vessel steels was studied. It is shown that for high Ni steels the flux effect is due to hardening and non-hardening mechanisms of radiation embrittlement.

Selective Removal of Atoms as a New Method for Manufacturing of Nanostructures for Various Applications

The paper demonstrates a possibility for effective modification of the thin-film material’ chemical composition, structure and physical properties as result of selective removal of atoms by the certain energy ion beam. One of the most promising results of this effect consists in developing the new technology for 3D micro-and nano-structures production for various applications.

Formation of conductive structures in insulate layers by selective removal of atoms technique

The structure and electric properties of initial oxides and metals (Bi, Ag, Cu, Ni, Co, Mo and W) produced by Selective Removal of oxygen Atoms technique (SRA) were studied. It was found a correspondence of electrical conductivity of SRA metals and pure sputtered metals films. At the same time, low resistance of some oxides, for instance CuO, will initiate big leakage currents inside the layer. Among the investigated materials special attention will be paid to SRA Bi, Mo and W because of the high values of contact resistance and puncture potential with initial oxides. It is shown the adaptability of Selective Removal of Atoms technique for formation of conductive insulated structures in layers for new micro and nano-electronic devices.

Study of phase transitions in NbN ultrathin films under composite ion beam irradiation

This work demonstrates implementation of Selective Displacement of Atoms (SDA) technique to change the crystal structure and atomic composition of thin superconductive film of NbN under low dose composite ion beam irradiation. All structure investigations were performed using High Resolution Transmission Electron Microscopy (HRTEM) technique by the analysis of Fourier transformation of bright field HRTEM images. It was found that composite ion beam irradiation induces the formation of niobium oxynitrides phases.

Selective Removal of Atoms as Basis for Ultra-High Density Nano-Patterned Magnetic and Other Media

The paper demonstrates a possibility for effective modification of the thin-film material’ chemical composition, structure and physical properties as result of selective removal of atoms by the certain energy ion beam. One of the most promising results of this effect is a production of devices with nanostructured high-density patterned magnetic media.

Electron Energy-Loss Spectroscopy Study of the Change in the Free-Electron Density in Thin Superconducting NbN Films under Ion-Beam Irradiation

The change in the free-electron density in ultrathin (5 nm) superconducting NbN films in the initial state and after irradiation by O+ ions to doses of (0.1–0.9) × 1017 cm–2 has been studied by electron energy-loss spectroscopy (EELS). The analysis has been performed on cross section samples prepared by the focused ion beam method, using plasmon oscillations with energies up to 50 eV. The radiation-induced replacement of nitrogen atoms with oxygen atoms in niobium nitride is found to change the electrical properties of the material, which leads to a decrease in the free-electron density with an increase in the irradiation dose.

Development of the DIFFRACALC program for analyzing the phase composition of alloys

The DiffraCalc software package is developed for automatic indexing of electron diffraction patterns. The program can operate with the existing base of X-ray diffraction data, containing information about the crystal structures of more than 100 thousands of materials. This information has been extracted from open sources. A compatibility with standard crystallographic files is implemented. In the indexing mode, the program automatically analyzes an experimental diffraction pattern, implementing a search for an appropriate phase from the list compiled by a user proceeding from the crystallographic database. The indexing mode algorithm is constructed using the method of pair reflections. In the simulation mode, the program calculates the electron diffraction pattern for a specified material, which is an additional way to verify the indexing results.

Electromagnetic Radiation of Micro and Nanomagnetic Structures with Magnetic Reversal

By means of the selective removal of atoms from the cobalt oxide under ion beam irradiation, micro and nanopatterned magnetic Co structures have been produced consisting of pseudo-single domain “bits” with different coercivity. With the magnetization reversal of those structures, electromagnetic radiation pulses arise whose characteristics have been investigated in detail. It was experimentally revealed about the huge increasing of the radiation intensity (up to ≈100 times) because of the synergetic effects depending on bit coercivities (varying with their shape anisotropy) and the distance between bits. In addition, there have been discovered the strong influence of the soft magnetic underlayer (of 50 nm thickness) on the process of magnetization reversal. Peculiar properties of the magnetic structure with and without the soft magnetic underlayer have been studied by magnetic force microscopy.