Mn,Zn, and Cd incorporation into the crystal lattice of indium antimonide

Using precision X-ray diffraction analysis, we have determined the unit-cell parameter of polycrystalline InSb plates and powders doped with Mn, Mn + Zn, and Mn + Cd. We have calculated the lattice parameter a of InSb〈M〉 solid solutions as a function of M content for both the ionic and covalent radii of the corresponding elements. Theoretical results and experimental data have been used to analyze the incorporation of the dopants into the InSb lattice.     

Thermal conductivity and electrical resistivity of cadmium arsenide (Cd3As2) in the temperature range 4.2–40 K

Results on electrical resistivity and thermal conductivity measured in the temperature range 4.2–40 K are presented for single-crystal and polycrystalline samples of Cd₃As₂. Hall effect has been studied at temperatures of 4.2, 77, and 300 K. The calculated value of the conduction electron concentration was in the range 1.87–1.95 10²⁴m^–3. Electrical resistivity of all investigated samples was independent of temperature up to about 10K and increased slowsly at higher temperatures. The thermal conductivity shows a maximum in the region in which the lattice component of thermal conductivity dominates. The strong anisotropy of the lattice component determines the anisotropy of the total thermal conductivity. The electronic component of thermal conductivity does not exhibit any anisotropy and shows a maximum at a temperature of about 300 K.Paper submitted to the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Magnetic-field tuning of the alloy-induced disorder in quaternary semimagnetic (Zn, Cd, Mn)Se quantum well structures

The influence of magnetic-field-induced tuning of the disorder on the line width of the lowest excitonic transition in diluted magnetic semiconductor (Zn, Cd, Mn)Se/ZnSe quantum well samples is studied by photoluminescence at 2 K and in magnetic fields up to 7.5 T. It is shown that the dependence of the photoluminescence line width on quantum well thickness can be explained as a sum of contributions of ZnSe barrier, (Zn, Cd, Mn)Se well and the interfaces.     

Preparation of nanocrystalline Ti,Mn, Co,Fe, and Zn oxides via heat treatment in aqueous solutions

Crystallization, coalescence, chemical reactions, and phase transformations in disperse systems based on hydrous Ti, Mn, Co, Fe, and Zn oxides during heat treatment in solutions of various ionic compositions are analyzed. The results indicate that the transformations in disperse systems follow the dissolution—precipitation mechanism and are accompanied by mass transfer between the solid phase and solution. Reactions are considered, using iron(III) oxyhydroxides as an example, that occur at the solution—crystal interface, and the possible compositions of crystal-forming complexes and the elementary reactions involved in the incorporation of the complexes into different faces of growing crystals of the equilibrium phase are established.Translated from Neorganicheskie Materialy, Vol. 41, No. 1, 2005, pp. 46–53.Original Russian Text Copyright © 2005 by Kleshchev.     

Immobilization of heavy metals (Pb, Cu, Cr, Zn, Cd, Mn) in the mineral additions containing concrete composites

The presented work determines the level of heavy metals (Pb+2, Cu+2, Zn+2, Cr+6, Cd+2, Mn+2) immobilization in the composites produced using Ordinary Portland Cement (OPC) as well as of binders containing large amount of mineral additives in its composition-siliceous fly ash (FA), fluidized bed combustion ash (FFA) and ground granulated blast furnace slag (GGBFS). Heavy metals were introduced to cementitious materials in the form of soluble salts as well as components of hazardous wastes (medical ash, metallurgical dust). It has been stated, that the level of heavy metals immobilization is combined with composites composition. Majority of analyzed heavy metals, added to binders' composition in the form of heavy metal salts achieves high level of immobilization, in mortar based on binder with 85% GGBFS and 15% OPC. The lowest immobilization level was reached for chromium Cr+6 added to hardening mortars as Na2Cr2O72H2O. The level ranges from 85.97% in mortars made on blended binder (20% OPC, 30% FFA and 50% GGBFS) to 93.33% in mortar produced on OPC. The increase of the so-called immobilization degree with time of hardened material maturing was found. This should be attributed to the pozzolanic or pozzolanic/hydraulic properties of components used; their effect on microstructure of hardened material is also important. Mineral additions enter the hydration reactions in the mixtures and favor the formation of specific microstructure promoting the immobilization of hazardous elements.     

Investigation of the thermal conductivity and density of isoamylbutyrate in a broad range of temperatures and pressures

Results of an experimental determination of the coefficient of thermal conductivity and density of isoamylbutyrate in the 1–490 bar pressure and 295.3–578.2°K temperature ranges are presented. The interrelation between the coefficient of thermal conductivity and the density is investigated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 6, pp. 1004–1006, June, 1977.     

Deviation from matthiessen's rule for thermal conductivity of quenched Zn-doped Cd crystals in the temperature range 5–20 K

Quantitative deviations from Matthiessen's rule (DMR) for thermal conductivity of quenched, Zn-doped Cd single crystals have been calculated on the basis of thermal and electrical conductivity measurements of the metal. The observed nonlinearity of DMR_max versusβ, whereβ is an electron-lattice defect interaction parameter, suggests that anisotropic effects of electron scattering are the most probable source of the DMR for Zn-doped Cd. We have also observed that DMR_max saturates itself, reaching a constant value for higher values ofβ.     

Adsorption of Cd, Cu, Ni, Pb and Zn on Sphagnum peat from solutions with low metal concentrations

This work investigates adsorption of metal ions on Sphagnum peat from solutions with environmentally relevant concentrations of metals. The peat moss is intended as an alternative, low-cost filter material for contaminated waters. Adsorption of Cd, Cu, Ni, Pb and Zn was studied in batch tests, and adsorption isotherms were determined. The kinetics of adsorption was analyzed using a second-order model and rate constants were calculated. An empirical model for predicting adsorption of metal ions at a given time was derived from these constants. Metal ions were removed in the descending order Pb>Cu>Ni>Cd>Zn. Relationship between the affinities of the metals to the peat active sites with chemical properties for the metals were indicated by the results. In addition, equilibration studies were performed at constant pH and ionic strength. The experimental data fitted the Freundlich equation. Both the uptake of metals and the Freundlich constants increased in line with increasing pH. The Freundlich exponent declined with higher initial concentrations, suggesting adsorption to sites with lower activity.     

First principles density functional calculations of half-metallic ferromagnetism in Zn1-xCrxS and Cd1-xCrxS

We employ the full-potential linearized augmented plane wave plus local orbital (FP-L/APW + lo) method based on spin-polarized density functional theory (DFT) in order to investigate the structural, electronic and magnetic properties of ordered dilute ferromagnetic semiconductors Zn_1?xCr_xS and Cd_1?xCr_xS (x = 0.25) in the zinc blende (B3) phase. For the exchange-correlation functional, the generalized gradient approximation GGA (Wu-Cohen 06) has been used. Results of calculated electronic band structures and density of states of these dilute magnetic semiconductors (DMSs) are discussed in terms of the contribution of Cr 3d⁵ 4s¹, Zn 3d¹⁰ 4s², Cd 4d¹⁰ 5s² and S 3s² 3p⁴ partial density of states. For Cr-based systems without n or p-type doping, the stability of the ferromagnetic spin state versus the antiferromagnetic state is predicted. Band structure and density of states studies show half-metallic ferromagnetic nature for both alloys, Zn_1?xCr_xS and Cd_1?xCr_xS. Calculations of the s–d exchange constant N₀α and p–d exchange constant N₀β clearly indicate the magnetic nature of these compounds. From the calculated total magnetic moments we observe that p–d hybridization reduces the local magnetic moment of Cr from its free space charge value and produces small local magnetic moments on the nonmagnetic Zn, Cd and S sites. The robustness of half-metallicity of Zn_1?xCr_xS and Cd_1?xCr_xS as a function of lattice constant is also discussed.     

Electrokinetic recovery of Cd, Cr, As, Ni, Zn and Mn from waste printed circuit boards: Effect of assisting agents

The printed circuit boards (PCBs) contains large number of heavy metal such as Cd, Cr, As, Ni, Zn and Mn. In this study, the use of electrokinetic (EK) treatment with different assisting agents has been investigated to recover the heavy metals from waste PCBs, and the effectiveness of different assisting agents (HNO₃, HCl, citric acid) was evaluated. The PCBs were first pre-treated by supercritical water oxidation (SCWO) process, then subjected to EK process. The heavy metal speciation, migration and recovery efficiency in the presence of different assisting agents during EK process were discussed. The mass loss of Cd, Cr, As and Zn during the SCWO process was negligible, but approximately 52% of Ni and 56% of Mn were lost in such a process. Experimental results showed that different assisting agents have significant effect on the behavior and recovery efficiency of different heavy metals. HCl was highly efficient for the recovery of Cd in waste PCBs due to the low pH and the stable complexation of Cl⁻. Citric acid was highly efficient for the recovery of Cr, Zn and Mn. HNO₃ was low efficient for recovery of most heavy metals except for Ni.     

Structure,Seebeck coefficient and DC electrical conductivity of Bi2Mn4O10 prepared by mechanochemical method

Journal of Materials Science: Materials in Electronics - Bismuth and manganese oxides were mixed as source-materials using the mechanochemical technique followed by heat treatment to prepare the...     

Structural disorder and solid state transformations in single crystals of Zn x Cd1−x S and Zn x Mn1−x S

Single crystals of Zn _x Cd_1−x S and Zn _x Mn_1−x S were grown from the vapour phase at 1100°C in the rangex=0·9 to 1. X-ray characterization shows that polytypes and disordered structures occur in Zn _x Cd_1−x S forx ≥ 0·94, whereas Zn _x Mn_1−x S displays disordered and polytype structures in the entire rangex=0·9 to 1. It is observed that Zn _x Cd_1−x S and Zn _x Mn_1−x S undergo a 2H-6H solid state transformation on annealing in vacuum around 600°C. Experimental analysis of the intensity distribution along the 10·L reciprocal lattice row as recorded on a single crystal diffractometer from partially transformed crystals shows that the mechanism of the transformation cannot be explained in terms of the one-parameter models of non-random faulting reported earlier. A two-parameter theoretical model with α representing the probability of random insertion of a fault in the 2H structure and β representing the probability of the growth of the 6H nucleus, is developed both for a deformation mechanism and a layer displacement mechanism. It is found that the theoretical model of non-random deformation faulting with β ≫ α approximates the actual mechanism of transformation in these crystals.     

Thermal conductivity and density of toluene in the temperature range 273–373 K at pressures up to 250 MPa

New experimental data on the thermal conductivity and the density of liquid toluene are presented in the temperature range 0–100°C at pressures up to 250 MPa. The measurements of thermal conductivity were performed with a transient hot-wire apparatus on an absolute basis with an inaccuracy less than 1.0%. The density was measured with a high-pressure burette method with an uncertainty within 0.1%. The experimental results for both properties are represented satisfactorily by the Tait-type equations, as well as empirical polynomials, covering the entire ranges of temperature and pressure. Furthermore, it is found that simple relations exist between the temperature dependence of thermal conductivity and the thermal expansion coefficient, and also between the pressure dependence of thermal conductivity and the isothermal compressibility, as are suggested theoretically.     

Defect structure and electrical conductivity in rapidly-quenched and slowly-cooled rhombohedral solid solutions of the system Bi2O3-BaO

The solid solubility limit, grain orientation, defect structure and electrical conductivity of solidified rhombohedral specimens in the Bi₂O₃-BaO system are described. The c-axes (in hexagonal notation) of solidified specimens were almost entirely oriented along the platelet/film thickness. Slow-cooling (∼ 10⁻²° Csec⁻¹) of the system gave solid solutions with substitutional type of 2BaO → 2Ba_Bi′ + 20+ V ₀ ^.. for 12 to 32 mol % BaO. High-temperature modification of slowly-cooled sample (16 mol % BaO) showed a conductivity of 8.8×10⁻¹ Ω⁻¹ cm ⁻¹ at 600° C along the conduction plane (perpendicular to the c-axis). Rapid quenching (∼ 10⁵° C sec⁻¹) produced solid solutions for 8 to 20 mol % BaO introducing interstitial Ba²⁺ (10–12 mol % BaO) and Schottky type defects such as V_Bi‴ and V _Bi ^‴ and V ₀ ^.. (16 to 20 mol % BaO), however the high-temperature modification of the rhombohedral structure could not be frozen.     

铝阳极中锌镉铟铁硅的原子发射光谱分析

研究了用原子发射光谱仪对铝阳极中的锌镉铟铁硅进行定量分析的方法,并与化学分析法进行了比较,结果令人满意。     

Synthesis, structure, and properties of compounds of the general formula Ba2AIIUO6 (AII = Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb)

Compounds Ba₂A^IIUO₆ (A^II = Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were synthesized by high-tem-perature solid-phase reactions. Their structures and properties were studied by X-ray diffraction, IR spec-troscopy, and reaction calorimetry.