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We report the structural and magnetotransport properties of ultrathin superparamagnetic Co/ZnO and Co/ZnAlO films deposited by sequentially sputtering Co layers and semiconductor layers. The films consisting of Co nanodots embedded in an amorphous semiconductor matrix exhibit large room temperature tunneling magnetoresistance with a maximum value of over 7%. The singlelayer- nanodot structures gradually develop in the films with thicknesses below 8 nm, where tunneling processes existing only between nanodots that lie in a plane are realized. The tunneling magnetoresistance ratio at room temperature is as high as 5% although the thickness of the Co/ZnAlO film is as thin as 3.2 nm. These single-layer-nanodot films having high tunneling magnetoresistance ratios and superparamagnetic behavior can be used in transparent nano-granular in gap sensors. [ABSTRACT FROM AUTHOR]

Co/ZnO films were deposited on glass substrates by magnetron sputtering at room temperature. The structure of the as-deposited films is studied by means of x-ray diffraction, x-ray photoelectron spectroscopy, and the zero-field-cooled and field-cooled magnetization curves. It is shown that the as-deposited samples consist of a mixture of regions of metallic Co and semiconducting ZnO. Large negative magnetoresistance of 26% and 11.9% are observed in the as-deposited Co/ZnO film with Co concentration of 50.7 at. % at 10 K and room temperature, respectively. Structural analysis, the temperature dependence of the conductivity and magnetoresistance reveal that the magnetoresistance is induced by spin-dependent tunneling between regions of conducting magnetic Co through the ZnO semiconducting barriers. The enhanced magnetoresistance in the low temperature regime may be related to the existence of higher-order tunneling processes between large Co regions mediated by small Co particles. [ABSTRACT FROM AUTHOR]

Facing the technical problem of pulse distortion caused by frequent resetting in the latest high‐performance silicon drift detectors, which work under high‐counting‐rate conditions, a method has been used to remove false peaks in order to obtain a precise X‐ray spectrum, the essence of which eliminates distorted pulses. Aiming at solving the problem of counting‐loss generated by eliminating distorted pulses, this paper proposes an improved method of pulse repairing. A 238Pu source with activity of 10 mCi was used as the measurement object, and the energy spectrum obtained by the pulse repairing method was compared with that obtained by the pulse elimination method. The ten‐measurement results show that the pulse repairing method can correct the counting‐loss caused by the pulse elimination method and increase peak area, which is of great significance for obtaining a precise X‐ray energy spectrum. A method is proposed to correct for the counting loss generated by removing distorted pulses in X‐ray spectra. The count rate obtained by the pulse repair method is increased by about 3% compared with that obtained by the pulse elimination method, and the sum of the peak area obtained by the pulse repairing method is increased by about 2.7% compared with that obtained by the pulse elimination method. [ABSTRACT FROM AUTHOR]

Non-stoichiometric colloidal quaternary Zn-Cu-In-S quantum dots (QDs) with different Cu content were prepared by a hot injection method and the enhanced electrogenerated chemiluminescence (ECL) were presented. Zn-Cu-In-S QDs were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis, photoluminescence (PL) and inductively coupled plasma mass spectrometer (ICP-MS). XRD results revealed the compositional homogeneity of the Zn-Cu-In-S QDs. Average particle size of Zn-Cu-In-S QDs samples were 2.3-2.8 nm. The HRTEM analysis indicated the high crystallinity. The ICP-MS measurements confirmed that the compositions of Zn-Cu-In-S QDs could be controlled precisely. Zn-Cu-In-S QDs were coated on glassy carbon electrode (GCE) with tetrabutylammonium hexafluorophosphate (TBAPF6). The ECL of Zn-Cu-In-S QDs were observed, which possessed extremely increase with tripropyl amine added as the coreactant. The ECL of Zn-Cu-In-S QDs were attribute to the copper related surface state. The Zn-Cu-In-S QDs modified GCE exhibited excellent ECL properties, environmentally-friendly and good stability, which implied further promising applications in bioanalysis. [ABSTRACT FROM AUTHOR]

The square-planar monomer NiL2 ( Ni1), L=2-ethoxy-6-( N-methyl-iminomethyl)phenolate, reacts with M(H2O)6(ClO4)2, M=Ni or Co, to form heptanuclear disks [Co xNi7− x(OH)6(L)6](ClO4)2 ⋅2 CH3CN ( Co x Ni7− x, x=0-7) and the co-crystal [Co xNi7− x(OH)6L6][NiL2](ClO4)2 ⋅2 CH3CN ( Co x Ni7− x -Ni1) under ambient conditions. It has proved possible to explore the bottom-up assembly process of Co x Ni7− x and Co x Ni7− x -Ni1 in real time. The final products have been characterized by thermogravimetric analysis, IR, elemental analysis, ICP-MS, and single-crystal X-ray diffraction. Time-dependent mass spectrometry (MS) revealed the following reaction steps: Ni1→[M2L3]+→[M4(OH)2L4]2+→[M7(OH)6L6]2+. In contrast, the reaction of Ni1 with Zn2+ only reaches halfway, and crystallographic evidence indicates a butterfly structure for [Zn2Ni2(OH)2Cl2] ( Zn2Ni2), an intermediate that is difficult to isolate in the above Ni-Co series. A summation method has been used to analyze the MS of bimetallic clusters with very similar atomic masses, as is the case for Co and Ni. The results provide ample information on the distribution of Co and Ni within each cluster and their statistical distribution within selected crystals. [ABSTRACT FROM AUTHOR]

Four new heterometallic coordination complexes, namely, {[Zn4Ln2(imdc)4(SO4)(H2O)8]·4H2O}n [Ln = Nd (1), Sm (2), Eu (3), Gd (4); H3imdc = imidazole-4,5-dicarboxylic acid], were hydrothermally synthesized by the reactions of Ln2O3 with imidazole-4,5-dicarboxylic acid and ZnSO4·7H2O and characterized by single-crystal X-ray diffraction, infrared spectroscopy (IR), elemental analysis (EA), thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD). The single-crystal X-ray diffraction analyses reveal that these polymers are isostructural and possess an interesting 3D pillar-layered architecture with 424·64 topology, in which 2D layers constructed by alternately arranged 1D right-/left-handed helical chains of [Zn2(μ5-imdc)]n bridged via dimeric Eu2 units are pillared by μ2-SO42− and μ3-imdc3− anions. The liquid fluorescence of compounds 1–3 at room temperature shows that these complexes are very good chemosensors for I− ion, and the response of the sensor is based on fluorescence quenching of Zn–Ln MOFs by iodine ions. [ABSTRACT FROM AUTHOR]

A (Ti,V)C/Fe composite was produced by a process which combines in situ synthesis with powder metallurgy technique using Ti, Fe, FeV and carbon powder. The microstructure of the Fe-(Ti,V)C composite was studied by scanning electron microscope and x-ray diffraction. The results show that the production of an iron matrix composite reinforced by (Ti,V)C particulates using the process is feasible. Fine (Ti,V)C particles are uniformly dispersed in the pearlite. The Fe-(Ti,V)C composite possesses excellent wear-resistance under the condition of dry sliding with heavy loads. [ABSTRACT FROM AUTHOR]

Abstract: A new 2-D inorganic–organic hybrid constructed from mixed-valence Cu(I/II) ions and mixed ligands, (H3sip=5-sulfoisophthalic acid, bipy=4,4′-bipyridine), has been synthesized and characterized by IR, TGA, XPS, EPR and single-crystal X-ray diffraction. Two different kinds of chains in the compound constructed from [CuO4] planar squares and [CuN2O] triangulars, respectively, further interconnect together to give rise to an interesting 2-D layer framework. The compound exhibits strong yellow emission at 445nm excited by 378nm in the solid state at room temperature. [Copyright &y& Elsevier]

A series of mixed-ligand coordination complexes, namely [Zn(L1)(oba)] (1), [Cd(L1)(oba)] (2), [Zn2(L2)(oba)2]·8H2O (3), [Cd2(L2)(oba)2]·2H2O (4), [Zn3(L3)(oba)3] (5), [Cd2(L3)(oba)2]·(L3) (6), [Cd(L4)(oba)]·H2O (7) and [Cd(L5)(oba)]·3H2O (8), where L1= 2-(2-pyridyl)imidazole, L2= 1,4-bis[2-(2-pyridyl)imidazol-1-yl]butane, L3= 1,4-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L4= 1,3-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L5= 1,2-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene and H2oba = 4,4′-oxydibenzoic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. In compounds 1and 2, oba2−, L1ligand and ZnIIor CdIIions assemble to form the parallel chains or parallel sheets which are linked by the weak hydrogen bonding and ππ stacking interactions to give the 2D supramolecular sheet or 3D supramolecular net, respectively. For 3, L2ligands connect [Zn(oba)] chains to generate a unusual (10,3)-b topological structure which is the first example for eight-fold interpenetrating framework based on the (10,3)-b net. In 4, L2ligands link [Cd(oba)] double-chains to give a 2D sheet which is assembled by ππ stacking interactions to obtain a 3D supramolecular net. In 5, L3ligands link ZnIIions from α-Po net formed by ZnIIions and oba2−anions to show a novel 3D 8-connected self-penetrating framework with the unreported (416·611·8) topological structure. In 6, the double-chains constructed by CdIIand oba2−anions are linked by one kind of L3ligand to form a layer-like structure which is assembled by ππ stacking interactions to show a 3D supramolecular structure. In 7, oba2−anions coordinate to CdIIcations to form chains which are connected by L4to form a four-fold interpenetrating diamond network. In 8, the weak hydrogen bonding and ππ stacking interactions connect the [Cd(L5)(oba)] chains to give a 2D supramolecular sheet. By careful inspections of the structures of 1–8, we believe that the different flexible and angular neutral ligands, coordination geometries of metal centers and weak interactions (hydrogen bonds and ππ stacking interactions) are crucial factors for the formation of the different structures. The photoluminescent properties of 1–8have been studied in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

A novel zinc-molybdenum(V) phosphate hybrid polymer, Zn[Mo6O12(OH)3(PO4)2(HPO4)2]2[Zn6(H2O)8(phen)4] ··· 6H2O (phen = 1,10-phenanthroline), was prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, FT-IR, TGA and EPR spectra. The crystal structure analyses show that the compound is built from two anionic hexameric polyoxomolybdophosphate [Mo6O12(OH)3(PO4)2(HPO4)2]7- moieties, bridged by a central octahedral Zn2+ centre. The sandwich-type Zn[Mo6P4]2 dimers are connected via additional Zn2+ polyhedra, forming a two-dimensional network polymer. The luminescent properties of the title compound are also discussed. [ABSTRACT FROM AUTHOR]

Aluminum nitride thin films with (100) orientation are necessary, as they are applied to surface acoustic wave devices. In this paper, A1N (100) nano thin films have been successfully deposited on Si (111) substrates using reactive magnetron sputtering. The films have been characterized by X-ray diffraction to determine their crystalline preferential orientation. The result shows that the experimental parameters including sputtering pressure, N2 concentration, target power and the distance from target to substrate (D) obviously affected crystal orientation of A1N thin films. It is found that the relationship between the mean free path of Al atoms and the distance D is important factor for the orientation of the A1N films. The optimum experimental parameters to deposit A1N (100) thin films have been found. [ABSTRACT FROM AUTHOR]

Three high-energy salts ( 3 , 4 and 5 ) based on oxy-bridged bis( gem -dinitro) furazan with potassium and nitrogen-rich cations were reported. Their structures were fully characterized and confirmed by NMR ( 1 H, 13 C), IR spectroscopy, elemental analysis and single crystal X-ray diffraction. The thermal decomposition behaviors were studied by DSC and TG methods. And, the decomposition process of 5 was studied by the thermolysis in-situ rapid-scan FTIR. The non-isothermal kinetics parameters were obtained by Kissinger’s and Ozawa’s methods, respectively. The activation entropy (Δ S ≠ ), activation enthalpy (Δ H ≠ ), activation Gibbs free energy (Δ G ≠ ) and the critical temperature of thermal explosion were calculated. [ABSTRACT FROM AUTHOR]

Doping of Bi12TiO20 with Ba ions was prepared by a chemical solution decomposition (CSD) method. Crystal structures of the prepared powders were confirmed by XRD and IR methods. Photocatalytic activities of the prepared samples were evaluated using methyl orange as a model organic compound. The result shows doping with 0.5 at.% Ba2+ can significantly increase the photoactivity of the Bi12TiO20 crystals. [Copyright &y& Elsevier]

Transparent and pale yellow calcium barium niobates (CaxBa1-xNb2O6) single crystals with larger Ca content ranging from 0.224 to 0.366 have been grown out by floating zone technique. The growth of CBN crystals in air is oriented along the <001> direction. The CBN crystals have been characterized by X-ray diffraction and X-ray single crystal diffraction. The composition uniformity of CBN-35 crystal rod has been checked by EPMA measurement. The deviations of Ca mole fraction between initial melt and the crystal are 0.1-1.4 mol%, which is much lower than crystals prepared by the Czochralski method. All the as grown crystals had high transmittance above 80% with increasing wavelength from about 500 nm. With increasing Ca content in crystal, symmetric bending mode v5 and symmetric stretching mode v2 broadened and moved to the low wave number. The relative intensity of Raman peak v5 compared to v2 increasing gradually indicates that the NbO6 octahedral distortion degree increased. [ABSTRACT FROM AUTHOR]

Abstract: Two new complexes based on 4-(benzimidazol-1-ylmethyl)benzoic acid (HL), (Sm2L6·H2O)n (1) and (LuL3)n (2), have been synthesized under the solvothermal condition and characterized by single-crystal X-ray diffraction, X-ray powder diffraction (PXRD), thermogravimetric analysis (TGA) and elemental analysis (EA) and IR spectra. The results show that both complexes are isomorphous and possess 2-D pillar-chained frameworks, consisting of 1-D triple-stranded double-helical (PPM/MMP) [Ln(η 2-O)(μ 2-OCO)2]n (Ln=Sm(1), Lu(2)) motif as chain and μ 3-(η 1:η 1:η 1)-bridging ligand L− as pillar, though they have different space groups of triclinic P-1 for 1 and monoclinic P21/c for 2. Two complexes represent the first example of 2-D lanthanide compound containing 4-(benzimidazol-1-ylmethyl)benzoic acid as the sole ligand. Additionally, the photoluminescent property of 1 is also discussed. [Copyright &y& Elsevier]

In an attempt to synthesize novel zirconium phosphate materials, a series of syntheses have been performed in a deep eutectic solvent (DES), composed of tetrapropylammonium bromide (TPABr) and oxalic acid. As a result, this DES does not act as a template provider in reaction probably owing to the steric effects of the longer chains of the TPA cation, and only the α-Zr(HPO4)2∙H2O (α-ZrP) phase has been achieved. However, after organic amine was added to the initial reaction mixture in a normal way, the additives did act as a template to induce the zirconium phosphate framework. For example, with 1,4-dimethylpiperazine as an additive, a novel layered compound, [C6H16N2]0.5Zr- (H0.5PO4)2∙H2O (denoted as ZrPO4-DES8) was obtained. Its structure was determined from single-crystal X-ray diffraction (XRD) data and consists of zirconium phosphate layers with the protonated 1 ,4-dimethylpiperazine and water molecules in between. Interestingly, the two layered materials as additives in a liquid lubricant exhibit excellent friction behavior with higher load-carrying and antiwear capacities in comparison to typical lubricant additives such as MoS2 and graphite, increase the PB value of the base oil by 27.2% and 8.5%, and decrease the wear scar diameter of the base oil by 43% and 36%, respectively. Scanning electron microscopy, XRD, and energy-dispersive X-ray spectrometry are used to investigate the lubricant behavior of those materials. [ABSTRACT FROM AUTHOR]