Inorganic Materials (v.49, #12)

Crucibles for Czochralski growth of isotopically enriched silicon single crystals by A. V. Gusev; V. A. Gavva; E. A. Kozyrev; H. Riemann; N. V. Abrosimov (1167-1169).
We have assessed isotope dilution during Czochralski growth of single crystals of stable silicon isotopes from crucibles of quartz glass of natural isotopic composition. A procedure has been developed for applying protective coatings from isotopically enriched silicon dioxide to crucibles. Comparison of the isotopic compositions of isotopically enriched polycrystalline silicon and 28Si, 29Si, and 30Si single crystals grown from it demonstrates that the use of protective coatings makes it possible to preclude isotope dilution in the crystal growth step.

Preparation and characterization of (MnZn)1 − x Fe x Sb solid solutions with the Cu2Sb structure by M. Budzyński; V. I. Mitsiuk; Z. Surowiec; T. M. Tkachenka (1170-1174).
(MnZn)1 − x Fe x Sb solid solutions with the Cu2Sb structure have been prepared through heterophase reactions. Their stability range is 0 < x ≤ 0.2. The magnetic interaction in the solid solutions has a ferromagnetic character. The Curie temperature and mass magnetization of the solid solutions have been determined, and the iron dopant has been shown not to participate in magnetic interaction.

Dielectric and optical properties of TlGa1 − x Er x S2 (x = 0, 0.001, 0.005, 0.01) single crystals by S. N. Mustafaeva; M. M. Asadov; E. M. Kerimova; N. Z. Gasanov (1175-1179).
TlGa1 − x Er x S2 (x = 0, 0.001, 0.005, 0.01) solid solutions, based on the layered compound TlGaS2, have been prepared by direct elemental synthesis. The effect of Er concentration on the dielectric and optical properties of the TlGa1 − x Er x S2 solid solutions has been studied. The results demonstrate that increasing the Er content of the TlGa1 − x Er x S2 solid solutions decreases the real part of their complex dielectric permittivity and increases their dielectric loss tangent. The conductivity (σ) of the TlGa1 − x Er x S2 solid solutions in the frequency range f = 1 to 35 MHz exhibits σ ∼ f 0.8 behavior, indicative of hopping charge transport through their band gap. We have evaluated the key parameters of this charge transport mechanism. We have studied temperature-dependent optical properties of the TlGa1 − x Er x S2 solid solutions. At temperatures in the range T = 77–200 K, the TlGa0.999Er0.001S2 solid solution has an absorption band near its fundamental absorption edge, which is due to transitions to a direct exciton state.

Electric-field effect on the electrical conductivity of InSe and InSe〈Dy〉 crystals by A. Sh. Abdinov; R. F. Babaeva; Ya. G. Gasanov; N. A. Ragimova; R. M. Rzaev (1180-1186).
We have studied the effect of external dc electric field on the dark conductivity $$left( {sigma _{d_0 } } ight)$$ of undoped and dysprosium-doped InSe single crystals having different initial dark conductivities ( $$sigma _{d_0 } = 2.5 imes 10^{ - 8}$$ to 10−2 S/cm at 77 K) and doping levels (∼10−5 to 10−1 at % Dy, respectively). At T ≤ 200–220 K and E ≥ 80–150 V/cm, the σd of the high-resistivity ( $$sigma _{d_0 } < 10^{ - 4}$$ S/cm) undoped and slightly doped (<10−2 at % Dy) crystals increases with increasing external electric field. The observed σd(E) behavior is shown to be unrelated to electric-field-induced heating of charge carriers or other effects of a high electric field when carrier scattering by various point defects and phonons prevails. It is primary due to partial disorder in the crystals, the presence of drift barriers in their empty energy bands, and the influence of injection and doping levels on the dimensions of the barriers.

Preparation of zirconium diboride nanopowders in a sodium tetraborate ionic melt by L. S. Volkova; A. G. Burlakova; S. E. Kravchenko; S. P. Shilkin (1187-1189).
Reactions between zirconium powder 10–15 μm in particle size and microcrystalline boron 10–20 μm in particle size in an Na2B4O7 ionic melt have been studied at temperatures from 600 to 850°C and reaction times from 5 to 10 h. The results demonstrate that ZrB2 forms starting at 750°C. According to scanning electron microscopy data, the ZrB2 powder consists of particles 90–95 nm in average size. The crystallite size evaluated from X-ray diffraction data is 85 nm.

Carbon phases resulting from Pt x Pd y (CO) z decomposition by I. V. Fedoseev; N. S. Gerasimova; K. V. Maramygin (1190-1193).
It has been found that spontaneous decomposition of carbonyl clusters with the general formula Pt x Pd y (CO) z at t ≥ 120°C leads to the formation of platinum-palladium sponge containing carbon phases—graphite, diamond, fullerenes, and carbon nanotubes resulting from the decomposition of CO molecules via the Boudoir reaction. The diamond has the form of grains up to 1 mm in size and filamentary crystals up to 2 cm in length and up to 30 μm in diameter, whose photographs are presented in the paper.

This paper presents a detailed study of the effect of the fluorescence of bulk substrates on the fluorescence intensity of vanadium nanofilms of various thicknesses and examines vanadium K α fluorescence enhancement by emission from the substrate. We calculate correction coefficients that take into account film-substrate interelement effects and demonstrate that it is appropriate to use unified auxiliary systems in analysis of real nanofilm structures.

Stabilization of spin skyrmions in magnetic materials and a two-dimensional electron gas by A. N. Kalinkin; V. M. Skorikov; E. M. Kozhbakhteev; A. E. Polyakov; S. A. Kuznetsova (1199-1202).
An integrodifferential equation for skyrmions in a magnetic material is solved by the finite-difference method with allowance for Dzyaloshinskii-Moriya and dipole-dipole interactions.

Synthesis of ultrafine magnesium oxide and titanium oxide powders by S. V. Lanovetskiy; V. A. Tikhonov; V. Z. Poilov (1203-1208).
The formation of magnesium and titanium hydroxides (differing in the rate of primary particle formation) and conversion of the hydroxides to ultrafine oxide powders of controlled size have been studied using scanning electron microscopy, X-ray diffraction, differential thermal analysis, and analysis of the particle size distributions of solid materials from scattered laser light intensity. The particle size of the synthesis products has been shown to be influenced by the initial concentration and nature of precursors and precipitants, ultrasonic processing, additions of low-molecular-weight organic compounds, and dehydration temperature and time.

Synthesis of mesostructured TiO2-based material and its functionalization with silver nanoparticles by A. Yu. Vakhrushev; V. V. Gorbunova; T. B. Boitsova; V. M. Stozharov; T. L. Lukanina (1209-1212).
We report the results of a template synthesis of a three-dimensional nanostructured material based on titanium(IV) oxide modified with silver nanoparticles. The chemical composition and structure of the material have been determined by scanning electron microscopy, IR spectroscopy, and X-ray diffraction.

Synchrotron X-ray diffraction study of nanostructured Er2O3-TiO2 (50–60 mol % Er2O3) solid solutions by L. P. Lyashenko; L. G. Shcherbakova; E. S. Kulik; R. D. Svetogorov; Ya. V. Zubavichus (1213-1219).
Monochromatic synchrotron X-ray diffraction data demonstrate that single-crystal and polycrystalline xEr2O3 · (1 − x)TiO2 (x = 0.5–0.6) solid solutions consist of a fluorite-like disordered (Fm3m) phase and a nanoscale (40–1000 nm) pyrochlore-like ordered phase (Fd3m) of the same composition in the range 0.5 ≤ x ≤ 0.57, coherent with the disordered phase. Reducing the density of structural defects in the unit cell of Er3TiO6.5 (x = 0.6) leads to a structural transformation of the pyrochlore-like phase into a Ta2O3-type ordered phase (Ia3), derived from the fluorite phase. In the composition range of the solid solutions (0.5 < x < 0.6), the lattice parameter of the fluorite-like phase follows Vegard’s law. The formation of nanodomains with different degrees of order is shown to be caused by the internal strain due to the high density of structural defects in their unit cells.

Ultrapurification of isotopically enriched materials for 40Ca100MoO4 crystal growth by V. V. Alenkov; O. A. Buzanov; A. E. Dosovitskii; V. N. Kornoukhov; A. L. Mikhlin; P. S. Moseev; N. D. Khanbekov (1220-1223).
This paper describes ultrapurification of isotopically enriched calcium and molybdenum compounds and 40Ca100MoO4 calcium molybdate growth charge in order to remove radioactive uranium, thorium, and radium impurities. 40Ca100MoO4 single crystals grown from such charges are needed for the fabrication of scintillator elements of the cryogenic detector for the AMoRE project: a search for 100Mo neutrino-less double-beta decay.

Phase equilibria in the Tl2MoO4-Pr2(MoO4)3-Hf(MoO4)2 system and crystal structure of TlPr(MoO4)2 by V. G. Grossman; B. G. Bazarov; L. A. Glinskaya; Zh. G. Bazarova (1224-1226).
Subsolidus (450–480°C) phase relations in the Tl2MoO4-Pr2(MoO4)3-Hf(MoO4)2 system have been studied by X-ray diffraction. The system has been shown to contain molybdates with the compositions Tl5PrHf(MoO4)6 (5: 1: 2), TlPrHf0.5(MoO4)3 (1: 1: 1), and Tl2PrHf2(MoO4)6.5 (2: 1: 4). Single crystals of the double molybdate TlPr(MoO4)2 have been grown for the first time from high-temperature solutions through spontaneous nucleation, and their crystal structure has been determined: tetragonal symmetry, sp. gr. P4/nnc, a = 6.3170(1) Å, c = 9.5529(2) Å, V = 381.204(12) Å3, Z = 2.

Heat capacity and thermodynamic properties of GaFeO3 in the range 330–900 K by V. M. Denisov; L. A. Irtyugo; L. T. Denisova; G. S. Patrin; N. V. Volkov (1227-1228).
The heat capacity of multiferroic GaFeO3 has been measured in a wide temperature range and the results have been used to evaluate its thermodynamic functions (enthalpy increment and entropy change).

Using concrete science as an example, we discuss priority issues in and principles and methodology of creating information terminological systems for inorganic materials science. The development of such systems builds on a typological approach, terminological field indexing methods, etc.