Inorganic Materials (v.50, #3)

Growth of Ga x In1 − x As y P1 − y /GaAs quantum dot arrays by ion beam deposition by I. A. Sysoev; M. L. Lunina; D. L. Alfimova; A. V. Blagin; D. A. Gusev; B. M. Seredin (215-221).
Experimental data are presented that demonstrate the possibility of producing GaInAsP quantum dots on GaAs by ion beam deposition. The morphology of the quantum dots and the effect of GaAs substrate temperature on parameters of GaInAsP quantum dot arrays have been studied by atomic force microscopy and scanning electron microscopy. We have determined the elemental composition of the quantum dots and obtained photoluminescence spectra of the GaInAsP/GaAs heterostructures.

Recrystallization behavior of zinc chalcogenides during hot isostatic pressing by E. M. Gavrishchuk; V. B. Ikonnikov; D. V. Savin (222-227).
This paper examines the effect of hot isostatic pressing (HIP) on the recrystallization behavior of zinc chalcogenides prepared by chemical vapor deposition (CVD). We discuss the mechanisms of this process in CVD ZnS, ZnSe, and ZnS x Se1 − x at high temperatures and pressures and consider conditions under which secondary recrystallization occurs during HIP and high-temperature annealing.

Fabrication and properties of CuInSe2/AgInSe2/CdS double heterojunction cascade solar cells by M. A. Abdullaev; A. B. Alhasov; D. Kh. Magomedova (228-232).
This paper reports the first study of the photoelectric properties of a double heterojunction cascade solar power converter based on the ternary compounds CuInSe2, AgInSe2, and CdS. We evaluate the photoelectric parameters of individual elements and a double-heterojunction converter. The efficiency of the cascade converter is η = 10.7%.

Heat capacity and thermodynamic functions of GaSe from 300 to 700 K by A. V. Tyurin; K. S. Gavrichev; A. V. Khoroshilov; V. P. Zlomanov (233-236).
The heat capacity of ɛ-GaSe has been determined by differential scanning calorimetry in the temperature range 300–700 K. Smoothed heat capacity data have been used to evaluate the thermodynamic functions of gallium monoselenide (entropy, enthalpy increment, and reduced Gibbs energy).

Phase relations and properties of alloys in the SnSe-DySe system by I. I. Aliev; J. I. Huseynov; M. I. Murguzov; Sh. S. Ismailov; E. M. Gojaev (237-240).
Phase relations in the SnSe-DySe system have been studied using differential thermal analysis, X-ray diffraction, microstructural analysis, microhardness tests, and density measurements, and its T-x phase diagram has been mapped out. The SnSe-DySe system contains a new ternary compound with the composition DySnSe2, which crystallizes in orthorhombic symmetry with unit-cell parameters a = 5.74 ± 0.02 Å, b = 10.49 ± 0.03 Å, and c = 11.66 ± 0.05 Å (Z = 7, V = 702 Å3, measured density ρmeas = 7.02 g/cm3, X-ray density ρx = 7.26 g/cm3). In addition, the system contains SnSe-based solid solutions, Sn1 − x Dy x Se (up to 4 mol % DySe). Their electrical conductivity and thermoelectric power have been measured as functions of temperature.

Physical properties of Hg1 − xy Cd x EuySe crystals by T. T. Kovalyuk; P. D. Maryanchuk; E. V. Maistruk; I. P. Koziarskyi (241-245).
We have studied the magnetic, optical, and kinetic properties of Hg1 − xy Cd x Eu y Se crystals. The behavior of their magnetic susceptibility can be accounted for by the presence of clusters of various sizes. The Hg1 − xy Cd x Eu y Se crystals are shown to be n-type. Their Hall coefficient (R H) is temperature-independent, which points to electron gas degeneracy. The optical band gap of the crystals has been determined.

IR absorption spectra of diamond nanoclusters are calculated by a semiempirical method (with PM3 parameterization), and the effects of cluster size, impurities, and native defects on the position and strength of absorption bands are examined.

Colloidal and transparent opal-matrix nanocomposites filled with europium-doped silica sols by S. N. Ivicheva; S. V. Kutsev; Yu. F. Kargin; N. A. Alad’ev (253-262).
Three-dimensional ordered opal-matrix composites filled with europium-doped silica sols have been produced using methods of colloid chemistry. According to elemental analysis data, the Eu concentration in the nanocomposites was ∼30 ppm. A uniform europium distribution over the tetrahedral and octahedral pores of the 3D opal matrix was ensured by repeatedly filling the opal pores with silica sols doped with europium salts or europium oxide. Varying high-temperature annealing conditions, one can control the microstructure of 3D ordered nanocomposites, producing opaline and transparent photonic crystals. The microstructure of opal photonic crystals has the form of an ordered fcc lattice of amorphous silica spheres, whose tetrahedral and octahedral pores are filled with mesoporous europium-doped glass. Partial sintering of the silica spheres and mesoporous glass in transparent photonic crystals results in a periodic arrangement of quantum dots enriched in Eu-doped silica.

Synthesis and properties of LiZr2(AsO4)3 and LiZr2(AsO4) x (PO4)3 − x by V. I. Pet’kov; M. V. Sukhanov; A. S. Shipilov; V. S. Kurazhkovskaya; E. Yu. Borovikova; I. Yu. Pinus; A. B. Yaroslavtsev (263-272).
The LiZr2(AsO4)3 arsenate and LiZr2(AsO4) x (PO4)3 − x solid solutions have been prepared through precipitation followed by heat treatment, and characterized by X-ray diffraction, X-ray structure analysis, IR spectroscopy, and impedance spectroscopy. We have established conditions for the crystallization of the arsenate and a continuous series of arsenate phosphate solid solutions (0 ≤ x ≤ 3), which have been obtained as two polymorphs: monoclinic and hexagonal. Using the Rietveld method, we have refined the crystal structures of the polymorphs of LiZr2(AsO4)3 (sp. gr. P21/n, a = 9.1064(2), b = 9.1906(2), c = 12.7269(3) Å, β = 90.844(2)°, V =1065.03(5) Å3, Z = 4; sp. gr. R $ar 3$ c, a = 9.1600(4), c = 22.9059(13) Å, V = 1664.44(14) Å, Z = 6) and LiZr2(AsO4)1.5(PO4)1.5. Their structural frameworks are built up of AsO4 tetrahedra—or (As,P)O4 tetrahedra occupied by arsenic and phosphorus atoms at random—and ZrO6 octahedra, with the lithium atoms in between. The ionic conductivity of the materials has been measured. The cation conductivity of monoclinic LiZr2(AsO4) x (PO4)3 − x with 0 ≤ x ≤ 1 has been shown to exceed the conductivity of lithium zirconium phosphate.

Microstructure and ion transport in Li1 + x Ti2 − x M x (PO4)3 (M = Cr, Fe, Al) NASICON-type materials by A. I. Svitan’ko; S. A. Novikova; I. A. Stenina; V. A. Skopets; A. B. Yaroslavtsev (273-279).
Li1 + x Ti2 − x M x (PO4)3 (M = Cr, Fe, Al) NASICON-type materials have been prepared by the Pechini process and solid-state reactions and characterized by X-ray diffraction, scanning electron microscopy, and impedance spectroscopy. We have identified the factors that determine the rate of ion transport in nanocrystalline and bulk samples at low and high temperatures. The effects of the preparation procedure and heterovalent doping on the ionic conductivity of the materials have been assessed. Heterovalent doping is shown to have a considerably stronger effect on the ionic conductivity in comparison with the microstructure of the materials.

Effect of interfaces on the magnetoelectric properties of Co/PZT/Co heterostructures by A. I. Stognij; N. N. Novitskii; S. A. Sharko; A. V. Bespalov; O. L. Golikova; A. Sazanovich; V. Dyakonov; H. Szymczak; V. A. Ketsko (280-284).
We have studied Co (film)/PZT (substrate)/Co (film) heterostructures with plane-parallel interfaces, produced by direct growth of cobalt films 0.5 to 3.5 μm thick on PZT surfaces smoothed to a subnanometer level (where PZT stands for a ceramic PbZr0.45Ti0.55O3 lead zirconate titanate ferroelectric substrate). The results demonstrate that they possess magnetoelectric properties comparable in magnitude to those characteristic of known structures but, in contrast to these latter, allow one to dispense with the condition that the volume fractions of the ferromagnetic and ferroelectric components be roughly equal. The interface is shown to play a key role in determining the magnetoelectric response of the heterostructures: above 9 mV/(cm Oe) (11.7 mV/A) in a magnetic field of 50 Oe (3980 A/m) at a frequency of 100 Hz and room temperature. The heterostructures are potentially attractive for use as nonvolatile sensors in household devices.

Magnetic properties of the mixed oxides Sr0.9La0.1Fe0.9Cd0.1O3 − δ and Sr0.75La0.75Fe0.75Cd0.75O4 − δ by L. A. Bashkirov; S. V. Slonskaya; N. N. Lubinskii; A. I. Galyas; K. I. Yanushkevich; I. M. Sirota (285-289).
We have found that the 77-K magnetization per formula unit of the SrFeO3 − δ ferrite, Sr0.9La0.1Fe0.9Cd0.1O3 − δ and Sr0.75La0.75Fe0.75Cd0.75O4 − δ mixed oxides, and SrLaFeO4 compound, calculated per mole of Fe ions, is 0.114μB, 0.024μB, 5 × 10−3 μB, and 4.3 × 10−2 μB, respectively. The resultant effective magnetic moment of the Fe3+ and Fe4+ ions $(mu _{effFe^{3 + } ,Fe^{4 + } } )$ in the Sr0.9La0.1Fe0.9Cd0.1O3 − δ solid solution in the temperature range 520–850 K is 3.61μB, and $mu _{effFe^{3 + } ,Fe^{4 + } } $ in Sr0.75La0.75Fe0.75Cd0.75O4 − δ and SrLaFeO4 in the temperature ranges 350–600 and 100–550 K is 5.89μB and 5.70μB, respectively.

Crystal structure and magnetic properties of Sr1 − x Sm x Fe12 − x Co x O19 solid solutions by Wu Ze; L. A. Bashkirov; S. V. Trukhanov; L. S. Lobanovskii; A. I. Galyas; S. V. Slonskaya (290-295).
Sr1 − x Sm x Fe12 − x Co x O19 (0 ≤ x ≤ 0.5) ferrites have been prepared by solid-state reactions in air at 1470 K using mixtures of samarium oxide, ferric oxide, Co3O4, and strontium carbonate. X-ray diffraction characterization showed that the samples with x < 0.2 were single-phase, whereas the samples with 0.2 ≤ x ≤ 0.5 contained α-Fe2O3 and those with 0.3 ≤ x ≤ 0.5 contained SmFeO3, CoFe2O4, and Sm2O3 as well. The highest degree of Sm3+ and Co2+ substitutions for Sr2+ and Fe3+ (x) in the SrFe12O19 ferrite at 1470 K was determined to be slightly less than 0.2. This substitution only slightly decreases the a and c parameters of the hexagonal lattice and the Curie temperature (T C) of the material. At temperatures of 5 and 300 K in magnetic fields of up to 14 T, we obtained magnetic hysteresis loops, which were used to evaluate the spontaneous magnetization (σ0), specific saturation magnetization (σs), and coercive force (σ H c) of the ferrites. The experimentally determined 5-K spontaneous magnetization per formula unit (n 0) of the x = 0.1 ferrite is 20.86μB, which coincides with the theoretical value calculated as n 0 = (8 × 5) − (3.9 × 5 − 0.1 × 3) = 20.8μB. At 300 K, the n 0 and σ H c of Sr0.9Sm0.1Fe11.9Co0.1O19 exceed those of SrFe12O19 by 7.7 and 9.9%, respectively.

Polymer-matrix nanocomposite gas-sensing materials by D. A. Pomogailo; S. Singh; M. Singh; B. C. Yadav; P. Tandon; S. I. Pomogailo; G. I. Dzhardimalieva; K. A. Kydralieva (296-305).
A new approach has been proposed for producing nanocomposite gas-sensing materials: in situ preparation of a polymer matrix and metal sulfide or oxide nanoparticles through the frontal polymerization of Co(II), Cd(II), Zn(II) and Pb(II) acrylamide complexes. The composition and structure of the nanocomposites thus obtained have been determined using X-ray diffraction, scanning and transmission electron microscopy, and Raman spectroscopy. The nanocomposites have been tested as room-temperature liquefied petroleum gas sensors.

Synthesis of organoyttroxanealumoxanesiloxanes and preparation of glass and glass-ceramics on their base by G. I. Shcherbakova; P. A. Storozhenko; N. B. Kutinova; N. S. Krivtsova; M. S. Varfolomeev; T. L. Movchan; D. V. Sidorov; M. G. Kuznetsova; T. M. Kuznetsova; G. Yu. Yurkov; A. A. Ashmarin (306-313).
We report the first synthesis of organoyttroxanealumoxanesiloxanes soluble in organic solvents. Their pyrolysis yields transparent glass-ceramic materials with a predetermined Al : Y : Si molar ratio [1]. We have studied the composition and properties of the organoyttroxanealumoxanesiloxanes and their pyrolysis products.

Effect of iron content on the sintering of ground basalt into ceramics by N. F. Drobot; O. A. Noskova; A. V. Khoroshilov; A. V. Steblevskii; S. V. Fomichev; V. A. Krenev (314-319).
Ground basalt from the Myandukha occurrence, Arkhangelsk oblast, was divided into magnetically enriched and magnetically deficient components by magnetic separation, and their chemical compositions were determined. We investigated the difference in thermal behavior between the two components using differential scanning calorimetry and thermogravimetry data and the mineralogical composition obtained by thermodynamic modeling of the basalt. The sintering behavior of the magnetic and nonmagnetic components of the ground basalt was examined, and some properties of the resultant ceramic materials were studied.

Thermodynamic properties of Eu-Pt and Al-Eu-Pt melts by M. I. Ivanov; V. V. Berezutskii; V. G. Kudin; M. A. Shevchenko; V. S. Sudavtsova (320-323).
The partial and integral enthalpies of mixing of Eu-Pt melts were determined by calorimetry at 1300 K in the composition range 0 < x Pt < 0.36. The first partial enthalpy of mixing of Pt was found to be −171 ± 2 kJ/mol. The thermodynamic properties of the Eu-Pt melts were modeled in terms of ideal associated solution theory in wide composition and temperature ranges. The results indicate that the activities of the components have large negative deviations from Raoult’s law and that the integral Gibbs energy and enthalpy of mixing have a minimum near x Pt = 0.7. The enthalpy and excess Gibbs energy of mixing of Al-Eu-Pt ternary melts were modeled using our and others’ data and Kohler’s equation.