Luminescence centres in pure AgCl crystals

The temperature dependence and the influence of pressure on band width of blue-green luminescence were measured in pure AgCl crystals. The comparison of results obtained with other published data support the existence of two luminescence centres (in the temperature ranges between 130–160°K and between 20–30°K).     

Preparation and photoelectric properties of antimony selenium iodide

The dependence of the photoelectric current on the wave-length was measured on SbSeI crystals in the temperature range of 83–293°K. The maximum of the internal photoeffect was found in the region of 720–740 nm for various crystals at room temperature. The temperature dependence of the forbidden band width of SbSeI crystals was deduced from the shift of the photoeffect maximum. The results were compared with the properties of homological compounds SbSI and BiSI.     

Dilatometric check of the analytic spectral distribution of normal lattice modes

An analytic expression is found for the coefficient of an approximately Gaussian distribution function which is convenient for studying this coefficient by means of dilatometric measurements of a solid. The temperature dependence calculated for this coefficient for a copper sample over the temperature range 84–975 °K indicates the degree to which the distribution function being studied corresponds to the actual spectrum in various temperature ranges in a solid.Translated from Izvestiya VUZ. Fizika, No. 12, pp. 50–53, December, 1969.     

Absorption coefficient in the wings of carbon dioxide bands in the 790–910-cm−1 spectrum range

The absorption coefficient of carbon dioxide is computed on the basis of the theory of spectral line wings during self-broadening and for broadening by nitrogen in the range 790–910 cm^–1 at 296 and 240°K temperatures. The contribution of the 18 vibrational-rotational bands of CO₂ to absorption is taken into account. The temperature dependence of the absorption coefficient was determined by the dependence of the classical intermolecular interaction on the temperature. The results of the computation are in satisfactory agreement with experiment.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 105–108, May, 1982.     

Electrophysical and photoelectric properties of (CdSe)1−x(CuInSe2)x solid solutions

The results are given of measurements of the electrophysical properties in the interval of temperatures 300–900°K and of the photoelectric properties at 300°K of (CdSe)_1–x–(CuInSe₂)_x solid solutions. It is shown that the electrophysical and photoelectric properties of the solid solutions depend on the composition and temperature. The forbidden-band widths calculated from the temperature dependence of the conductivity and from the photoconductivity spectrum, respectively, vary from 1.68 and 1.77 eV for initial compound CdSe to 1.25 and 1.18 eV for the solid solution Cu_0.1Cd_0.9In_0.1Se_1.1.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 41–43, January, 1992.     

Temperature dependences of the flow and critical shear stresses of dispersion-hardening alloys

A study was made of the temperature dependences of the flow stress _0.1 (T) and of the critical shear stress _cr(T) of Cu-15% A1-(1–2)% Co, Cu-8% A1-(2–2.8)% Co, and Cu-4% A1–2% Co alloys containing noncoherent intermetallic particles. In the case of single crystals at temperatures 77–673° K there was a good agreement between the theoretically calculated values of the Orowan hardening and those found experimentally, so that the dependence _cr(T) was governed by the temperature dependence of the shear modulus G(T). For polycrystalline samples the usual dependence of the mechanical propertiesties on the grain size was not observed. At temperatures from 77 to 473–573°K the dependence _0.1 (T) was similar to the dependence G(T) and a good agreement was observed between the theoretically calculated dispersion hardening effects with those found experimentally. At temperatures T > 473–573°K the deformation was influenced greatly by grain-boundary glide, which enhanced the dependence _0.1 (T) compared with that expected theoretically.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 85–91, June, 1980.     

Proton channeling in silicon at various temperatures

A study was made of the channeling of 6. 72 MeV protons in a silicon crystal at 100–800 °K. The experimental dependence of the limiting channeling angle agrees with the theoretical prediction. A relation is found between the relative number of channeled protons and the temperature.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 6, pp. 60–63, June, 1970.     

Structure and electrical properties of thin films of copper selenide

Electron-diffraction and electron-microscope methods were used to investigate the structure of Cu₂Se films of close to stoichiometric composition. It is shown that in polycrystalline and single-crystal films of thickness >400Å at room temperature, the tetragonal modification is stable, which at temperatures above 400°K is transformed into the cubical modification. In thinner films d<400 Å the cubical modification of copper selenide is stable at room temperature. A sharp peak is observed at 400°K on the temperature dependence of the resistance; this is connected with the phase transition. At room temperature, copper selenide is a degenerate p-type semiconductor with carrier concentration 5 · 10²²–8 · 10²⁰ cm^–3, depending on the thickness of the film.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 90–94, August, 1973.     

Temperature dependence of IR band strength for polyethylene

IR spectra at 150° K and detailed temperature curves for 150–310° K for the 965, 985, 1175, 1890, and 2010 cm^–1 bands are reported. The background bears a direct relation to temperature, whereas the bands have a negative temperature coefficient of intensity. The weakening of the 944 cm^–1 band is irreversible.     

Hall coefficient of alloys of the Nd-Y system at temperature range 100–800°K

Studies were conducted on the concentration and temperature dependence of the Hall coefficient of alloys of the Nd-Y system within the entire region of concentrations and in the temperature range from 100 to 800°K. The results obtained are discussed from the point of view of electron theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 32–36, January, 1973.The authors wish to express their thanks to G. F. Kobzenko for supplying the alloys, and to A. E. Bryukhanov and V. F. Nemchenko for their assistance in the work.     

Temperature dependence of the stationary photocurrent in doped sillenite type crystals

The temperature dependence of the photocurrent in doped sillenite-type crystals is investigated in the temperature range 80–300°K. In the region of low temperatures thermally activated photocurrent is observed, while at high temperatures quenching is observed. In a number of specimens the temperature quenching section is absent. The results are explained within the framework of a multilevel recombination model involving slow and fast recombination centers as well as capture levels.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 85–89, June, 1985.     

Effect of interstitial impurities on the temperature dependence of the resistance to edge dislocation motion in α-iron

The temperature dependence of the macroscopic elastic limit of iron polycrystals with various carbon content is investigated. On their basis, the temperature dependence of the resistance to edge dislocation motion is determined. At T<295°K it is linear and increases with carbon concentration owing to the reduction of the activation volume, whereas the activation energy is independent of the carbon concentration. It is shown that to start the dislocation motion from the source, a larger stress is required than for its motion in the grain bulk, and that this stress increases with carbon concentration.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 85–89, March, 1984.     

Magnetic properties of thorium and uranium borides and U1−xThxB4 solid solutions

The dependence of the magnetic susceptibility on the temperature in the compound UB₄ and system U_1–xTh_xB₄ has been studied in the temperature range 140–1300°K. It has been established that the paramagnetic susceptibility does not obey the Curie-Weiss law. The experimental results are interpreted on the basis of the Stoner model of collectivized electrons which also makes it possible to explain the magnetic properties of other borides of thorium and uranium.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, No. 7, pp. 45–48, July, 1982.     

Recombination luminescence in KI-Tl phosphor

The X-ray luminescence and the optical scintillation of certain specimens of KI-Tl with varying activator content when excited by X-ray radiation at T=105 ° K were studied. The temperatute dependence of the brilliance of scintillation and luminescence measured under pulse conditions was found to be complex, and in the temperature range 105 °–240 ° K a series of alternating increases and decreases in these values was observed. At the same time a definite parallelism was found in the changes in brilliance of the luminescence and the scintillation. An increase in brilliance of specimens excited at 105 ° K after heating up to 133 ° K was observed and investigated. The regularities found are explained by the redistribution of hole centers. The data obtained confirm the importance of the part played by the electron-hole mechanism in the migration of the energy of the basic material to the centers of luminescence in KI-Tl phosphor.     

СВОЙСТВА СУРЬМЯНИСТОГО КАДМИЯ, ЛЕГИРОВАННОГО СЕРЕБРОМ, ПРИ НИЗКИХ ТЕМПЕРАТУРАХ

The temperature dependence of the resistivity and the Hall coefficient of Ag doped CdSb single crystals was investigated in the temperature range of 1.5–300°K. It was shown that Ag in CdSb gives shallow acceptor levels with an activation energyE _a =3.5×10^–3 eV. Presence of the admixture band determines the electrical properties of crystals at low temperatures. The energy width of this band is about 10^–3 eV for slightly doped crystals.     

Pressure dependence of the electric field gradient at Cd impurities in antimony

The electric field gradient at¹¹¹Cd in Antimony was studied at hydrostatic pressures up to 7 kbar at 150 K, 293 K and 473 K. The logarithmic pressure derivatives, dlnq/dP, were found to be –67, –37 and –26 Mbar^–1 respectively. The isotropic volume dependence derived from these values was found to be positive and largely responsible for the anomalous temperature dependence, previously observed.     

Magnetism of some rare-earth dodecaborides

The temperature dependence of the magnetic susceptibility has been recorded for the dodecaborides of terbium, dysprosium, holmium, erbium, and thulium over the range 90–1200°K. A theoretical model is tested, which is based on localized 4f electrons and the Van Vleck theory of paramagnetism. An explanation is suggested for the interaction between the rare-earth ions in the higher borides, which have the framework structure of boron itself.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 96–101, December, 1977.     

Current carrier mobility in manganese-doped cadmium telluride

The possibility of substantial influence of a manganese impurity on the magnetic and optical properties of CdTe, which is explained by the state and interaction of the Mn 3d⁵-electron spins in the CdTe crystal lattice, is shown in [1–3]. An investigation of the influence of the Mn impurity on current carrier scattering in this material is of interest. To this end, the temperature dependence of the Hall mobility of electrons in CdTe-Mn single crystals is investigated in this paper in the temperature range 77–435°K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 24–28, April, 1982.     

Low-temperature diffusion of silicon atoms in the nickel-nickel silicide-silicon system

The diffusion of Si atoms from a silicon substrate through a layer of nickel monosilicide into a Ni film is investigated in the temperature interval 470–670°K by the method of radioactive isotopes. The distribution profile of Si in NiSi and Ni is derived. The GB-diffusion parameters of Si in NiSi are determined. It is shown that when T>570°K there is an increase in the thickness of the initial NiSi layer, and a kink appears on the in D=f(1/T) curve. The associated change in the activation energy of diffusion from 0.43 (470–570°K) to 0.72 eV (570–670°K) is explained by the formation of Ni-Si and Si-O type complexes. The diffusion of silicon atoms accompanied by complex-formation processes determines the evolution of the resistivity of the Ni-NiSi-Si contact.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 78–83, March, 1985.     

Electrical conductivity and photoconductivity of single crystals of lithium hydride

Nonactivated LiH crystals and crystals of LiH with Mg, In, Tl, Sn, Sb, and Bi impurities are investigated. Photoconductivity is found in luminescent crystals. The temperature dependence of the electrical conductivity and photoconductivity in the temperature range of 100–570 ° K is measured. Volt-ampere characteristics of the dark current and photocurrent in fields up to 10⁴ V/cm at various temperatures are obtained. Data is presented on the inertia of the photocurrent and its dependence on the intensity of the exciting light. Conclusions are drawn concerning some connection of LiH photoconductivity with the type of activating impurity, the absence of a connection with the brightness of the luminescence, and the specific role of photoconductivity in color centers.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 10, pp. 94–98, October, 1971.