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Chernivtsi, Ukraine

Okulov V.I.,RAS Institute of Metal Physics | Al'Shanskii G.A.,RAS Institute of Metal Physics | Lonchakov A.T.,RAS Institute of Metal Physics | Govorkova T.E.,RAS Institute of Metal Physics | And 3 more authors.
Physics of Metals and Metallography | Year: 2012

The article presents the experimental results concerning the role of cobalt impurities in low-temperature electrical conduction and in the Hall concentration of electrons in crystals of mercury selenide. In the limit of small concentrations of the impurities, a slow variation of the electron concentration was found as a function of impurity content, which can correspond to a donor character of the impurity d levels of cobalt atoms located in the conduction band of the host crystal under conditions of hybridization. Characteristic features have been observed in the concentration and temperature dependences of the electrical conductivity, similar to those that manifest themselves in crystals with hybridized states of iron impurities. As a result, the set of data obtained on crystals with cobalt impurities, including the previously published data on the concentration dependence of the Curie constant and on the temperature dependence of thermopower, can be used on a qualitative level as an experimental substantiation of the previously predicted existence of two donor hybridized electron states of a cobalt impurity atom in the conduction band. © Pleiades Publishing, Ltd., 2012.

Okulov V.I.,Russian Academy of Sciences | Govorkova T.E.,Russian Academy of Sciences | Zhevstovskikh I.V.,Russian Academy of Sciences | Lonchakov A.T.,Russian Academy of Sciences | And 5 more authors.
Low Temperature Physics | Year: 2013

Experimental evidence of the possible existence of spontaneous spin polarization of the electron system in hybridized states formed by transition element impurity atoms in the conduction band of semiconducting crystals is examined. The details of a quantitative interpretation of experiments on the temperature dependence of the specific heat and elastic moduli of mercury selenide crystals with iron impurities confirm the feasibility of establishing the presence of electron spin polarization in this type of experiment, as well as the possible existence of polarization in the crystals studied here. Theoretical arguments support the observation of a thermodynamic anomalous Hall effect owing to spontaneously polarized donor electrons from low-concentration impurities. © 2013 AIP Publishing LLC.

Lonchakov A.T.,RAS Institute of Metal Physics | Okulov V.I.,RAS Institute of Metal Physics | Govorkova T.E.,RAS Institute of Metal Physics | Andriichuk M.D.,Chernovtsy National University | Paranchich L.D.,Chernovtsy National University
JETP Letters | Year: 2012

An anomalous magnetic-field-independent contribution to the Hall resistance of mercury selenide crystals with a small iron impurity has been discovered in room-temperature experiments. This contribution has been shown to be due to spontaneous polarization of the electron system of hybridized impurity states. The theoretical explanation of the effect based on the thermodynamic description of dissipationless electron current in the spontaneously polarized electron system has been proposed. © 2012 Pleiades Publishing, Ltd.

Ushenko V.A.,Chernovtsy National University | Sidor M.I.,Chernovtsy National University | Marchuk Yu.F.,Bukovina State Medical University | Pashkovskaya N.V.,Bukovina State Medical University | Andreichuk D.R.,Bukovina State Medical University
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2014

A Mueller-matrix model is proposed for analysis of the optical anisotropy of protein networks of optically thin nondepolarizing layers of biological tissues with allowance for birefringence and dichroism. The model is used to construct algorithms for reconstruction of coordinate distributions of phase shifts and coefficient of linear dichroism. Objective criteria for differentiation of benign and malignant tissues of female genitals are formulated in the framework of the statistical analysis of such distributions. Approaches of evidence-based medicine are used to determine the working characteristics (sensitivity, specificity, and accuracy) of the Mueller-matrix method for the reconstruction of the parameters of optical anisotropy and show its efficiency in the differentiation of benign and malignant tumors. © 2014 Pleiades Publishing, Ltd.

Zhevstovskikh I.V.,Ural Federal University | Okulov V.I.,RAS Institute of Metal Physics | Gudkov V.V.,Ural Federal University | Sarychev M.N.,Ural Federal University | And 3 more authors.
Journal of Low Temperature Physics | Year: 2015

Influence on elastic moduli of donor electron d-states of cobalt impurities has been investigated in mercury selenide crystals. Experiments have been carried out at the frequency of 53 MHz in the temperature interval of 1.3–100 K. Softening of the (Formula presented.) modulus below 10 K has been observed in the impurity crystals in contrast with the (Formula presented.) and (Formula presented.) moduli those have exhibited hardening at cooling typical for dielectric and semiconductor crystals. The softening of the elastic modulus has been interpreted as manifestation of hybridization of the impurity d-states in the conduction band of the crystal. Comparison of theoretical calculations with experimental data has been proved to be in good agreement and has made it possible to determine the parameters characterizing the hybridized electron states. © 2015 Springer Science+Business Media New York

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