Institute of Materials Science Problems

Chernivtsi, Ukraine

Institute of Materials Science Problems

Chernivtsi, Ukraine
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Zvereva E.,Moscow State University | Savelieva O.,Moscow State University | Ibragimov S.,SuperOx Chemical Company | Titov Ya.,Moscow State University | And 2 more authors.
Solid State Phenomena | Year: 2011

We have studied the magnetic susceptibility, magnetization and electron paramagnetic resonance (EPR) in the diluted magnetic semiconductor Pb 1-x-yMgxYbyTe. The magnetic susceptibility of this system is a superposition of the matrix diamagnetism, the paramagnetic contribution of electrons localized in the ytterbium band, and the Curie-Weiss paramagnetism provided by Yb3+ ions. The concentration of Yb3+ ions monotonically increases with the ytterbium content, while a significant fraction of ytterbium ions remains in a nonmagnetic Yb2+ state. A pronounced hyperfine structure was revealed in the EPR spectra. It was ascribed to the interaction between the electron magnetic moment of an unfilled electron shell of Yb3+ ions and nuclear magnetic moment of the 173Yb isotope. The estimated values of the effective g-factor (g≈1.997± 0.002) and the hyperfine-interaction constant ( 173A=0,56 cm-1) were found to be almost independent of both alloy composition and temperature.


Zvereva E.A.,Moscow State University | Savelieva O.A.,Moscow State University | Ibragimov S.,SuperOx Chemical Company | Samokhvalov E.,Moscow State University | And 2 more authors.
Solid State Phenomena | Year: 2011

We report on the magnetic properties of novel diluted magnetic semiconductors Pb1-x-ySnxCryTe revealing ferromagnetism at temperatures higher than room temperature. Depending on chromium concentration the Curie temperature varies in a wide range (150÷360 K) and effective magnetic moment achieves 1 μB upon an increase of chromium doping level. Electron spin resonance (ESR) spectra in the paramagnetic phase were satisfactory approximated by a single Dysonian line. Effective g-factor tends to the saturation value g=2.08±0.01, while the linewidth passes through a minimum in the vicinity of magnetic ordering transition and then broadens with an increase of the temperature. In ferromagnetic phase the pronounced distortion and splitting of the ESR spectra into two lines occurs due to additional ferromagnetic contribution to absorption.


Ivashenko V.I.,Institute of Materials Science Problems | Pogrebnyak A.D.,Sumy State University | Skrinski P.L.,Institute of Materials Science Problems | Rogoz V.N.,Sumy State University | And 3 more authors.
IOP Conference Series: Materials Science and Engineering | Year: 2015

Nanocompositefilms Nb-Al-N produced by magnetron sputtering were researched in this work. Two stable crystalline structural states were found in the films: NbNch and solid solution B1-NbxAl1-xNyO1-y, and also an amorphous component associated with aluminum oxynitride with reactive magnetron sputtering. Sensitivity of substructural characteristics was set up to the current supplied to Al target and their relationship with the characteristic nanohardness and Knoop hardness. Recent changes in the range of 29-33.5 GPa and 46-48 GPa, respectively. Initial principle calculations of phases NbN and Nb2AlN and also heterostructures of NbN/AlN were carried out for the interpretation of the results. The work was performed as a part of two complex state programs: "Development of nanostructured superhard coatings formation foundations with high physical-mechanical properties" (number 0112u001382) and "Physical principles of plasma technologies for complex processing of multicomponent materials and coatings" (number 0113u000137c). © Published under licence by IOP Publishing Ltd.


Skipetrov E.P.,Moscow State University | Golovanov A.N.,Moscow State University | Kovalev B.B.,Moscow State University | Knotko A.V.,Moscow State University | And 2 more authors.
Semiconductor Science and Technology | Year: 2012

We study the galvanomagnetic properties in weak magnetic fields (4.2 T 300 K, B 0.07 T) and the Shubnikov-de Haas effect (T = 4.2 K, B 7 T) in single crystal Pb 1-x-ySn xV yTe alloys under variation of alloy composition (x = 0.050.20, y 0.01) and hydrostatic compression up to 15 kbar. The increase of vanadium impurity content leads to the p-n-conversion and to a transition in the insulating phase due to the pinning of Fermi level by the donor-type deep vanadium impurity level situated under the bottom of the conduction band. We found that pressure induces a decrease of the activation energy of the vanadium level, the n-p-inversion of the conductivity type at low temperatures and an insulatormetal transition. In the metallic phase, a sharp increase of the Hall mobility (up to 3×10 5cm 2 V 1 s 1) and appearance of Shubnikov-de Haas oscillations are observed at helium temperature. The pressure and temperature coefficients of vanadium deep level energy are determined, and the diagram of the electronic structure rearrangement for Pb 1-x-ySn xV yTe under pressure is proposed. © 2012 IOP Publishing Ltd.


Skipetrov E.P.,Moscow State University | Golovanov A.N.,Moscow State University | Kovalev B.B.,Moscow State University | Mousalitin A.M.,Moscow Institute of Steel And Alloys | And 2 more authors.
Journal of Physics: Conference Series | Year: 2012

The galvanomagnetic properties in weak magnetic fields (4.2≤T≤300 K, B≤0.07 T) and the Shubnikov-de Haas effect (T=4.2 K, B≤7 T) in the single crystal Pb 1-x-ySn xV yTe (x=0.05-0.20, y≤0.01) alloys at atmospheric pressure and under hydrostatic compression up to 15 kbar have been investigated. We found that the increase of the vanadium impurity content leads to the p-n-conversion, transition to the insulating phase and to the pinning of Fermi level by the deep impurity level, lying under the bottom of the conduction band. Under pressure a decrease of the activation energy of the vanadium level, the n-p-inversion of the conductivity type at low temperatures and an insulator-metal transition occur. The pressure and the temperature coefficients of vanadium deep level energy are determined and the diagram of the electronic structure rearrangement for Pb 1-x-ySn xV yTe under pressure is proposed.


Skipetrov E.P.,Moscow State University | Golovanov A.N.,Moscow State University | Kovalev B.B.,Moscow State University | Skipetrova L.A.,Moscow State University | And 3 more authors.
AIP Conference Proceedings | Year: 2011

We study the structure, composition and galvanomagnetic properties (4.2≤T≤300K,B≤0.07T) of the single crystal Pb 1-x-ySn xV yTe, Pb 1-yTi yTe and Pb 1-ySc yTe under variation of the alloy composition (x≤0.20,y≤0.025). An increase of the impurity content leads to a change in the free carrier concentration due to pinning of the Fermi level by the donor deep impurity levels. The energetic position of these levels in the investigated alloys is estimated. © 2011 American Institute of Physics.

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