Growth and electrical properties of mercury indium telluride single crystals

A novel photoelectronic single crystal, mercury indium telluride (MIT), has been successfully grown by using vertical Bridgman method (VB). The crystallinity, thermal and electrical properties of the MIT crystal were investigated. The results of X-ray rocking curve show that the as-grown MIT crystal has good crystal quality with the FWHM on (3 1 1) face of about 173 in. DSC measurement reveals that the Hg element is easy to solely evaporate from the compound when the temperature is higher than 387.9 °C in the open system. Hall measurements at room temperature show that the resistivity, carrier density and mobility of the MIT crystal were 4.79 × 10² Ω cm, 2.83 × 10¹³ cm⁻³ and 4.60 × 10² cm² V⁻¹ s⁻¹, respectively. The reduction of carrier mobility and the increase of the resistivity are related to the adding of In₂Te₃ into HgTe, which changes the energy band structure of the crystal.     

Crystal structure and physicochemical properties of a new organic condensed phosphate (C7H10NO)3P3O9·4H2O

Chemical preparation, X-ray characterization, IR spectroscopy and thermal analysis of a new cyclotriphosphate: (C₇H₁₀NO)₃P₃O₉·4H₂O abbreviated as OACTP, are reported. This mixed organo-mineral compound crystallizes in the monoclinic system with P2₁/n space group, the unit cell dimensions are: a = 6.605(3) Å, b = 26.166(3) Å, c = 18.671(8) Å, β = 91.95(3)°, Z = 4 and V = 3255(2) Å³. The structure was solved using a direct method and refined to a reliability R-factor of 0.043 using 3931 independent reflections (I > 2σI). Atomic arrangement exhibits infinite (P₃O₉·2H₂O)_n³ⁿ⁻ chains connected by organic cations. The thermal behavior and the IR spectroscopic studies of this new compound are discussed.     

Extraordinary role of Ce–Ni elements on the electrical and magnetic properties of Sr–Ba M-type hexaferrites

The structural, electrical and magnetic behavior of Sr_0.5Ba_0.5−xCe_xFe_12−yNi_yO₁₉ (where x = 0.00–0.10; y = 0.00–1.00) hexaferrite nanomaterials are reported in this paper. The structural analysis indicates that the Ce–Ni doped Sr–Ba M-type hexaferrite samples synthesized by the co-precipitation method are stoichiometric, single magnetoplumbite phase with crystallite sizes in the range of 35–48 nm. The dc-electrical resistivity of the pure Sr–Ba hexaferrite is enhanced to almost 10² times by doping with Ce–Ni contents of x = 0.06; y = 0.60. The dielectric constant and dielectric loss tangent decrease to values 14 and <0.2, respectively, by increasing the frequency up to 1 MHz. Small relaxation peaks at frequencies >10⁵ Hz are observed for the samples with Ce content of x > 0.06. The values of saturation magnetization increase from 66.32 to 84.33 emu/g and remanance magnetization from 42.64 to 56.01 emu/g but coercivity decreases from 2.85 to 1.59 kOe by substitution of Ce–Ni. Sharp ferri-paramagnetic transition is observed in the samples, which is confirmed by DSC results. Ce–Ni substitution acts to reduce the electron-hopping between Fe²⁺/Fe³⁺ ions and also improves the magnetic properties. These characteristics are desirable for their possible use in microwave and chip devices.     

Synthesis, structure refinement at 296 K and physico-chemical characterizations of KMnHP3O10

Potassium manganese(III) monohydrogentriphosphate KMnHP₃O₁₀ was synthesized by flux method and characterized by single-crystal X-ray diffraction, crystallizes in the monoclinic system with centric space group C2/c. The parameters of the unit cell are a = 12.104(1), b = 8.287(1). c = 9.150(1) Å, β = 110.97(1)° and Z = 4. The structure was solved at 296 K using 893 independent reflections and refined until R(F) = 0.022; wR(F²) = 0.045. The atomic arrangement of the title compound consists of MnO₆ octahedra linked by hydrogentriphosphate anions to form a three-dimensional framework containing tunnels parallel to the c-axis where the K⁺ cations are inserted. The structure of KMnHP₃O₁₀ contains a single Mn site which is surrounded by typical Jahn-Teller [2 + 2 + 2] distorted octahedron. The title material has been also characterized by different physico-chemical techniques: powder X-ray diffraction, IR, NMR and CI spectroscopies and DTA-TGA-DSC thermal analysis.     

Crystal structure and physicochemical properties of a new organic monohydrogen monophosphate hydrate

Crystals of 2(2-ammonium ethyl ammonium) ethanol monohydrogenmonophosphate monohydrate: (C₄H₁₄N₂O)HPO₄·H₂O abbreviated as AEEHP, were prepared and grown at room temperature. The AEEHP crystallizes in the monoclinic system with the P2₁/a space group. Its unit cell dimensions are: a = 4.8236(2), b = 28.429(2), c = 7.0711(6) Å, and β = 94.881(4)° with V = 966.14(11) ų and Z = 4. The structure of this compound was determined by using X-ray data collection on single-crystal. The AEEHP structure is built up from infinite inorganic HPO₄²⁻ chains parallel to the a-axis, alternating with infinite chains of H₂O molecules. These chains are interconnected by organic groups so as to build a three dimensional arrangement. In the present work, we describe the crystal structure, thermal behavior and IR analysis of this new compound.     

Martensitic transformation behaviors of Ti-rich Ti–Ni alloy fibers fabricated by melt overflow

Ti₅₀Ni₅₀, Ti_50.5Ni_49.5, Ti₅₁Ni₄₉ and Ti_51.5Ni_48.5 fibers were fabricated by melt overflow process. The rapid solidification can increase the solubility above the equilibrium solubility. The effects of the rapid solidification of Ti-rich Ti–Ni alloys on the microstructure, transformation temperatures and shape memory characteristics are investigated. The addition of 0.5 at.% Ti in Ti₅₀Ni₅₀ alloy greatly increases the transformation temperature. However, the transformation temperatures decrease again for Ti content exceeding 51 at.%. Results of thermal cycling tests under various constant stress levels reveal that the recoverable elongation associated with B2–B19 martensitic transformation of Ti_50.5Ni_49.5 fibers is two times larger than that of Ti_51.5Ni_48.5 alloy fiber.     

Rietveld refinement and spectroscopic studies of sodium lead fluoroapatite lacunaire synthesized by hydrothermal method

The structure of NaPb₉(PO₄)₆F(H₂O)_0.33, isostructural with apatite, was determined by X-ray powder diffraction methods and the result of Rietveld refinement is P6₃/m, a = 9.76396(8) Å and c = 7.27520(9) Å. The final refinement led to R_F = 5.4%, R_B = 6.6%. In the tunnel, the water molecule (O_w) and F⁻ ions appear to be located in 2b and 4e sites, with occupancies of 0.028(6) and 0.075(8), respectively. In the M(1) and M(2) sites the occupancies of Pb and Na are 0.282(3)/0.051(3) and 0.467(5)/0.033(5), respectively. The formula assigned to the compound is [Pb_3.38(4)Na_0.62(4)](1)[Pb_5.60(6)Na_0.40(6)](2)(PO₄)₆F_0.90(10)(H₂O)_0.33(7)□_0.77(17), where □ = vacancy. The assignment of the observed frequencies in the Raman and infrared spectra is discussed on the basis of a unit-cell group analysis and by comparison with fluor and chloroapatite analogs. The result of ³¹P and ²³Na magic angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies confirmed the structural results.     

Crystal structure and physicochemical properties of a new organic dihydrogenmonoarsenate

A new organic dihydrogenmonoarsenate (C₃H₉N₂O₂)H₂AsO₄ (abbreviate as ECAs) is prepared by reacting H₃AsO₄ with ethyl carbazate. This compound crystallizes in the monoclinic crystal system, space group P2₁/n. Unit cell parameters are a = 4.8370(2) Å, b = 24.6270(2) Å, c = 7.6311(5) Å, β = 92.948(4)°, with, Z = 4 and ρ_m = 1.800 g cm⁻³. The structure is solved, using the direct methods and refined against F² to a reliability R factor of 0.0475. The compound is characterized by infinite [H₂AsO₄]_nⁿ⁻ ribbons, parallel to the a-direction, connected by organic cations and forming layers localized at y = 0 and 1/2. The cohesion of the framework is ensured by hydrogen bonds N(O)-H?O. The thermal properties of the compounds are investigated as well as the IR properties supported by group theoretical analyses.     

Synthesis and crystal sructure of a new dihydrogenomonophosphate (4-C2H5C6H4NH3)H2PO4

Chemical preparation, crystal structure, calorimetric, and spectroscopic investigations are given for a new organic-cation dihydrogenomonophosphate, (4-C₂H₅C₆H₄NH₃)H₂PO₄ in the solid state. This compound crystallizes in the orthorhombic space group Pbca with the following unit cell parameters: a=8.286(3) Å, b=9.660(2) Å, c=24.876(4) Å, Z=8, V=1991.2(7) Å³, and D_X=1.442 g cm⁻³. Crystal structure was solved with a final R=0.054 for 3305 independent reflections. The atomic arrangement coaled described as H₂PO₄⁻ layers between which are located the 4-ethylanilinium cations.     

Formation and stability of anatase phase of phosphate incorporated and carbon doped titania nanotubes

Phase transformation analysis of the phosphate containing and carbon doped titania nanotubes, prepared by a simple anodization method, reveals complete transformation from amorphous to anatase phase in air between 360 and 400 °C. Activation energies for formation of anatase phase are evaluated and compared for the two types of titania nanotubes. A detailed analysis of the phase transformation characteristics and stability of the anatase phase is reported.     

Subsolidus phase equilibria and the Li5Nd4FeO10 phase in the Li2O-Nd2O3-Fe2O3 system

A survey of the subsolidus phase equilibria in the system Li₂O-Nd₂O₃-Fe₂O₃ was made at subsolidus temperatures in the range 1000-1050 °C. A ternary phase was identified. The phase is centered on Li₅Nd₄FeO₁₀, with a cubic lattice a = 11.9494 Å. The compound melts incongruently at 1105 °C. The magnetic susceptibility was measured in the temperature range 4-300 K. The compound is paramagnetic in the temperature range 150-300 K and follows the Curie-Weiss law. At about T_N = 10 K, a long-range magnetic ordering is observed.     

Microstructure and martensitic transformation in Si-coated TiNi powders prepared by ball milling

Si was coated on the surface of Ti–49Ni (at%) alloy powders by ball milling in order to improve the electrochemical properties of the Si electrodes of secondary Li ion batteries and then the microstructure and martensitic transformation behavior were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Ti–Ni powders coated with Si were fabricated successfully by ball milling. As-milled powders consisted of highly deformed Ti–Ni powders with the B2 phase and amorphous Si layers. The thickness of the Si layer coated on the surface of the Ti–Ni powders increased from 3–5 μm to 10–15 μm by extending the milling time from 3 h to 48 h. However, severe contamination from the grinding media, ZrO₂ occurred when the ball milling time was as long as 48 h. By heating as-milled powders to various temperatures in the range of 673–873 K, the highly deformed Ti–Ni powders were recovered and Ti₄Ni₄Si₇ was formed. Two-stage B2–R–B19′ transformation occurred when as-milled Si-coated Ti–49Ni alloy powders were heated to temperatures below 873 K, above this temperature one-stage B2–B19′ transformation occurred.     

Martensitic transformation behavior in Ti–Ni–X (Ag,In, Sn,Sb, Te,Tl, Pb,Bi) ternary alloys

The microstructures and transformation behaviors of Ti–Ni–X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti–Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti–Ni matrices with a limited solubility (≤1.0 at%), while Sb, Te, Tl, Pb and Bi were not soluble. Two-stage B2-R-B19′ transformation occurred in Ti–48.8Ni–1.2Ag, Ti–49.0Ni–1.0In and Ti–49.0Ni–1.0Sn alloys, while one-stage B2-B19′ transformation occurred in Ti–49.0Ni–1.0Ag, Ti–49.0Ni–1.0Sb, Ti–49.0Ni–1.0Te, Ti–49.0Ni–1.0Pb and Ti–49.0Ni–1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19′ transformation (Hv 250–368) was much larger than that (<Hv 200) of the alloys displaying the B2-B19′ transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti–Ni–X (X = non-transition elements) alloys.     

A study on the phase transition and characteristics of rare earth elements doped BaTiO3

Non-reducible dielectric composition satisfying X8R specifications (−55 to 150°C, ±15%) for automotive applications was investigated in a BaTiO₃-MgCO₃-MnO₂-rare earth elements (La, Pr, Gd, Tb, Dy, Ho, Er, Yb, Lu) system. In the cases of Er, Yb, Lu-substituted samples, a transition of the Curie point shifted to a higher temperature was observed. The peak shift toward higher temperatures indicated that the tetragonal phase became more stable at the high temperature. The ionic radius of rare earth elements was found to be an important factor in controlling the temperature dependency of the dielectric properties. Especially, smaller ionic radii of rare earth elements such as Yb and Lu were effective dopants to meet the X8R temperature-capacitance characteristics.     

Characterisation of ferroelectric lithium ammonium sulphate binary systems

This paper presents various thermo-electric studies on ferroelectric lithium ammonium sulphate (LAS) binary systems. LAS crystals were grown and characterized with powder X-ray diffraction technique. Different studies like dilotometry, electrostriction and phase transition temperatures were investigated. Dilotometry and dielectric studies confirmed the phase temperatures obtained from differential scanning calorimetry (DSC). It was interesting to note that the ferroelectric region was unaltered in all the binaries. Odd proportions of the binaries were more pronounced than their even counter parts as regards to the electrical and thermal properties.     

Spectroscopic and thermal behavior of ZnHg(SCN)4

The synthesis and purification of zinc mercury thiocyanate, ZnHg(SCN)₄ (ZMTC), are described. The identity of the synthesized compound was characterized by elemental analysis, X-ray powder diffraction, infrared, Raman, and UV/Vis/NIR transmission spectra. The thermal stability and thermal decomposition of ZMTC crystal were investigated by means of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The intermediates and final products of the thermal decomposition were identified by X-ray powder diffraction (XRPD).     

Physicochemical properties and theoretical explanation of ZnCd(SCN)4 crystal

The crystal density and Mohs hardness of zinc cadmium thiocyanate (ZCTC), ZnCd(SCN)₄ have been measured at room temperature. The specific heat of the crystal is 699.5 J mol⁻¹ K⁻¹ at 300 K. The thermal expansion coefficient (TEC) along the a and c axes, respectively, is interpreted on the basis of crystal structure. The thermal decomposition process is characterized by thermogravimetry analysis and differential scanning calorimetry (TGA/DSC). The intermediates and final products of the thermal decomposition were identified by X-ray powder diffraction at room temperature. The high-temperature effect in air on the optical transmission of the crystal was also studied.     

In situ NiTi/Nb(Ti) composite

This paper reports on the creation of a series of in situ NiTi/Nb(Ti) composites with controllable transformation temperatures based on the pseudo-binary hypereutectic transformation of NiTi–Nb system. The composite constituent morphology was controlled by forging and rolling. It is found that the thickness of the NiTi lamella in the composite reached micron level after the hot-forging and cold-rolling. The NiTi/Nb(Ti) composite exhibited high damping capacity as well as high yield strength.     

Synthesis and characterization of 2-amino-3-methylpyridinium dihydrogenomonoarsenate

A new crystal of 2-amino-3-methylpyridinium dihydrogenomonoarsenate has been prepared and characterized by X-ray crystallography, thermal analysis and spectroscopic studies. This compound crystallizes in the triclinic space group with a = 7.2689 (2) Å, b = 8.0975 (2) Å, c = 8.3969 (4) Å, α = 77.09 (3)°, β = 79.20 (3)°, γ = 88.16 (2)°, V = 473.19 (3) Å³, Z = 2. The crystal structure was solved and refined to R = 0.027 with 3375 independent reflections. The atomic arrangement can be described as (H₂AsO₄⁻)_n polymeric chains anchoring the 2-amino-3-methylpyridinium cations through short hydrogen bonds. All the ring atoms of the organic entity are coplanar. The exocyclic N atom is an electron receiving center, which is consistent with features of imino resonance evidenced by bond lengths and angles. Solid-state ¹³C and ¹⁵N CP-MAS-NMR spectroscopies are in agreement with the X-ray structure. Ab initio calculations allow the attribution of carbons and nitrogen to the independent crystallographic sites.     

Crystal structure, thermal analysis and IR spectroscopic investigation of (C6H9N2)H2XO4 (X = As, P)

Crystals of 2-amino-4-methylpyridinium dihydrogenmonoarsenate (C₆H₉N₂)H₂AsO₄ and 2-amino-4-methylpyridinium dihydrogenmonophosphate (C₆H₉N₂)H₂PO₄ have been prepared and grown at room temperature. These materials are isotypic with the following unit cell dimensions (C₆H₉N₂)H₂AsO₄: a = 12.4415(5) Å, b = 6.8224(3) Å, c = 11.3524(5) Å, Z = 4, V = 963.60(6) Å³; (C₆H₉N₂)H₂PO₄: a = 12.4410(9) Å, b = 6.7165(3) Å, c = 11.3417(5) Å, Z = 4, V = 925.09(10) Å³. The common space group is Pnma. The structure of these compounds has been determined by X-ray data collection on single crystals of (C₆H₉N₂)H₂AsO₄ and (C₆H₉N₂)H₂PO₄. Due to the strong hydrogen-bond network connecting the H₂XO₄ groups, the anionic arrangement must be described as a linear organization. The chains composed by the macroanion spread along the b-direction, approximately centered by x = 0 and 1/2. All atoms of the structure, except one oxygen atom, are located in the mirror planes situated at y = 1/4 and 3/4, imparting an internal mirror symmetry to the anionic and the cationic entities. The linear macroanions are crossed by organic cations lying in mirrors perpendicular to the b-direction; this atomic arrangement is then described by a three-dimensional network of hydrogen bonds, built up by two types, O–HO bonds inside the chains and N–HO bonds linking adjacent chains. The thermal properties of both compounds are investigated as well as the IR properties supported by group theoretical analyses.