E. Kh. Mukhamedzhanov

Publications (10)8.86 Total impact

• Article: Radiation defect clustering in graphite studied by synchrotron radiation scattering

  A. I. Ryazanov, M. V. Koval’chuk, E. Kh. Mukhamedzhanov, V. N. Peregudov, S. T. Latushkin, A. N. Morkovin, M. M. Borisov, V. N. Unezhev
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  ABSTRACT: The formation of radiation defect clusters as interstitial dislocation loops in pyrographite irradiated by 20-MeV carbon ions in a cyclotron has been studied by means of synchrotron radiation scattering. The experimental data are interpreted in terms of the Krivoglaz model and the model of deformation domain formation by dislocation loops. Parameters of the pyrographite crystal lattice in the deformed state upon ion irradiation have been determined using experimental data on the shift and broadening of the Bragg peaks. The results of experiments and their theoretical analysis indicate that the phenomena of the crystal lattice densification (shrinkage) and the radiation-induced swelling (increase in volume) observed for graphite irradiated by fast neutrons in a nuclear reactor can be studied in model experiments on charged particle accelerators using irradiation of the samples with carbon ions at much lower doses and significantly shorter exposure times.
  Journal of Experimental and Theoretical Physics 05/2012; 107(1):102-112. · 1.03 Impact Factor
• Article: Coexistence of superconductivity and ferromagnetism in the Nb(500 Å)/Fe(39 Å)/[Si(34 Å)/Mo(34 Å)]40/Si nanostructure

  V. L. Aksenov, Yu. V. Nikitenko, Yu. N. Khaidukov, S. N. Vdovichev, M. M. Borisov, A. N. Morkovin, E. Kh. Mukhamedzhanov
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  ABSTRACT: The results of polarized neutron reflectometry investigations of the magnetic state of the Nb(500 Å) superconductor-57Fe(39 Å) ferromagnet-Si(34 Å)/Mo(34 Å)]40 superconductor nanostructure in the temperature range 2–60 K in the magnetic field with a strength of 0.5 kOe are presented. A decrease in magnetization in an iron layer for the transition of Nb(500 Å) and [Si(34 Å)/Mo(34 A)]40 layers to the superconducting state has been found.
  Journal of Surface Investigation X-ray Synchrotron and Neutron Techniques 05/2012; 3(4):495-499. · 0.34 Impact Factor
• Article: “Forbidden” reflections in resonant diffraction of synchrotron radiation in yttrium aluminum garnet Y3Al5O12

  E. Kh. Mukhamedzhanov, M. V. Kovalchuk, M. M. Borisov, E. N. Ovchinnikova, A. P. Oreshko, V. E. Dmitrienko
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  ABSTRACT: The purely resonant Bragg reflections (13, 13, 0) and (14, 0, 0) in yttrium aluminum garnet Y3Al5O12 at energies near the K absorption edge of yttrium have been studied experimentally and theoretically. The anisotropic tensor atomic factor of yttrium corresponding to dipole-dipole resonance transitions depends on three independent parameters changing with energy. The intensities of the reflections (14, 0, 0) and (13, 13, 0) are shown to depend on the parameter difference f 1(E) − f 2(E) and the parameter f 3(E), respectively, which are attributable to distortions of the wave functions of the excited atoms and change greatly with photon energy E. Studying various reflections has allowed one to determine the various components of the tensor atomic factor and to compare them with the results of numerical calculations.
  Journal of Experimental and Theoretical Physics 04/2012; 112(1):94-101. · 1.03 Impact Factor
• Article: Resonant diffraction of synchrotron radiation in rubidium dihydrophosphate crystals

  E. Kh. Mukhamedzhanov, M. V. Kovalchuk, M. M. Borisov, E. N. Ovchinnikova, E. V. Troshkov, V. E. Dmitrienko
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  ABSTRACT: Purely resonant Bragg reflections 006, 5$ \bar 5 $ \bar 5 0, and 666 in a rubidium dihydrophosphate (RbH2PO4) crystal at the K edge of rubidium have been experimentally and theoretically investigated. These reflections remain forbidden when the resonant dipole-dipole (E1E1) contribution to the resonant atomic factor is taken into account; they may be due to the dipole-quadrupole (E1E2) transitions as well as to the anisotropy atomic factor, which is caused by thermal atomic displacements (thermally induced contribution) and/or local jumps of hydrogen atoms. A numerical simulation showed that, at room temperature (experimental conditions), the thermally induced contribution to the “forbidden” reflections is dominant.
  Crystallography Reports 04/2012; 55(2):174-181. · 0.47 Impact Factor
• Source

  Available from: M. A. Andreeva

  Article: Localization of an ultrathin buried Fe layer in a multilayer structure Nb/Fe/[Mo/Si]40/SiO2 by means of X-ray standing waves

  M. A. Andreeva, A. D. Gribova, E. E. Odintsova, M. M. Borisov, M. V. Kovalchuk, E. Kh. Mukhamedzhanov
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  ABSTRACT: An analysis of the influence of standing waves on the angular dependencies of the fluorescent yield from an ultrathin iron layer buried inside a multilayer structure of Nb(50 nm)/Fe(3.9 nm)/[Si/Mo(6.77 nm)]40/SiO2 is presented. These angular dependencies of reflectivity and FeK α-fluorescence yield were measured at the Station for high-precision X-ray optics (HPXO) of the Kurchatov Center for Synchrotron Radiation and Nanotechnology. The measured data was analyzed with the help of our FLUO software package. As a result of the complex treatment of reflectivity and Fe fluorescent yield data, the depth profile for iron atomic density was restored.
  Moscow University Physics Bulletin 04/2012; 64(4):437-441. · 0.20 Impact Factor
• Source

  Available from: Victor Kohn

  Article: Coplanar three-beam X-ray diffraction study in TeO2 single crystal using synchrotron radiation

  A. E. Blagov, M. V. Koval’chuk, V. G. Kohn, E. Kh. Mukhamedzhanov, Yu. V. Pisarevsky, P. A. Prosekov
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  ABSTRACT: The results of the first experimental study of coplanar three-beam X-ray diffraction in a paratellurite (TeO2) single crystal using synchrotron radiation on a Kurchatov synchrotron radiation source are presented. Four cases with (220, 371), (220, 464), (220, 370), and (110, 557) indices have been investigated. In all cases the change of the rocking curve shape of the weak reflection has been observed due to the multibeam interaction resulting in the appearance of two peaks in the reflection curve corresponding to two scattering mechanisms: amplitude and resonance. The origin of the insufficient resolution in the experiments has been considered. It has been shown that the obtained data correspond to the results of the computer simulation.
  Journal of Surface Investigation X-ray Synchrotron and Neutron Techniques 04/2012; 5(5):822-827. · 0.34 Impact Factor
• Source

  Available from: Alexey Oreshko

  Article: Absolute intensity and phase of the resonant X-ray scattering from a germanium crystal

  E. Kh. Mukhamedzhanov, M. M. Borisov, A. N. Morkovin, A. A. Antonenko, A. P. Oreshko, E. N. Ovchinnikova, V. E. Dmitrienko
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  ABSTRACT: The 222 and 600 reflections near the germanium absorption K edge were studied on the Kurchatov synchrotron radiation source. The energy spectrum of the 222 reflection is caused by the interference of the weak nonresonant and purely resonant contributions to the tensor atomic factor, whereas the 600 reflection is purely resonant. The energy dependence of the magnitude and phase of the resonant contribution to the scattering amplitude was determined from a change in the interference pattern. The numerical simulation of the energy spectra of reflections with the inclusion of the dipole-quadrupole and thermally induced contributions shows that the latter is dominant at room temperature. PACS numbers78.70.Ck
  JETP Letters 04/2012; 86(12):783-787. · 1.35 Impact Factor
• Source

  Available from: Victor Kohn

  Article: Source focusing and coherent imaging of a microscopic object at weak spatial coherence of the synchrotron radiation beam

  A. A. Snigirev, V. G. Kohn, E. Kh. Mukhamedzhanov, I. I. Snigireva, A. G. Maevskii, V. V. Kvardakov, M. V. Kovalchuk
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  ABSTRACT: Experimental results are presented on the measurement of a holographic (phase-contrast) image of a boric fiber (100-μm-diameter boric cylinder with a 20-μm-diameter tungsten core) and on radiation focusing by Fresnel zone plates using the Kurchatov synchrotron radiation source. By comparison of the obtained hologram with theoretically calculated data, the vertical size of the source was determined to be 325 ± 25 μm. This value was also confirmed by measuring the half-width of the direct image of the source. Features of image recording on a photographic film are discussed.
  Journal of Surface Investigation X-ray Synchrotron and Neutron Techniques 01/2007; 1(1):1-6. · 0.34 Impact Factor
• Article: The Use of a Gas‐Flow Proportional Counter for the Energetical Analysis of Photoelectrons under X‐Ray Diffraction Conditions

  M. V. Kovalchuk, E. Kh. Mukhamedzhanov
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  ABSTRACT: New possibilities of an X-ray standing wave field in the case of photoemission are described. It is shown experimentally that using a gas-flow proportional counter for the separation of photoelectrons with definite energy it is possible to make a step-by-step non-distructive structure analysis of the near-surface layer of the crystal.Die Möglichkeiten eines stehenden Röntgenwellenfeldes für die Photoemission werden beschrieben. Es wird experimentell gezeigt, daß es mit einem Gasdurchfluß-Proportionalzähler zur Separation yon Photoelektronen mit definierter Energie möglich ist, eine zerstörungsfreie Schritt-für-Sebritt-Strukturanalyse der oberflächennahen Schichten des Kristalls durchzuführen.
  physica status solidi (a) 02/2006; 81(2):427 - 432. · 1.21 Impact Factor
• Article: Detection of ultrathin amorphous layers by means of specular reflection under grazing-incidence diffraction conditions

  V A Bushuev, R M Imamov, E Kh Mukhamedzhanov, A P Oreshko
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  ABSTRACT: The anomalous behaviour of the specular reflection under the condition of noncoplanar grazing-incidence x-ray diffraction have been revealed and studied. The phenomenon is analysed theoretically in a perfect crystal and in a crystal coated with an amorphous film. The high sensitivity to the presence and thickness of an several-nanometers thick amorphous films has been shown. Both the thickness and the density of the native oxide film coating the surface of a silicon single crystal were determined experimentally.
  Journal of Physics D Applied Physics 06/2002; 35(12):1422. · 2.54 Impact Factor