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Sample records for br cu fe

  1. Magnetically separable CuFe2O4/AgBr composite photocatalysts: Preparation, characterization, photocatalytic activity and photocatalytic mechanism under visible light

    Science.gov (United States)

    Zhao, Yalei; Lin, Cuiping; Bi, Huijie; Liu, Yonggang; Yan, Qishe

    2017-01-01

    The CuFe2O4 and CuFe2O4/AgBr composites with different CuFe2O4 contents were prepared by a facile sol-gel and hydrothermal method, respectively. The as-synthesized photocatalysts were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectrum (UV-vis DRS). Their magnetic properties, photocatalytic degradation activities on methyl orange (MO) and tetracycline hydrochloride (TC) solution and photocatalytic mechanism were investigated in detail. The results revealed that the CuFe2O4/AgBr composites exhibited significantly higher photocatalytic activities than the pure CuFe2O4. The enhanced photocatalytic activity could be attributed to the matched band structure of two components and more effective charge transportation and separations. In addition, the quenching investigation of different scavengers demonstrated that h+, rad OH, rad O2- reactive species played different roles in the decolorization of MO and degradation of TC.

  2. PRR performance of Cu- and CuBr-vapor lasers

    Science.gov (United States)

    Fedorov, V. F.; Evtushenko, Gennadiy S.; Klimkin, Vladimir M.; Polunin, Yu. P.; Soldatov, Anatoly N.; Sukhanov, Viktor B.

    1998-06-01

    Results obtained from comparative analysis of the pulse repetition rate performance of Cu- and CuBr-vapor lasers operated at high pump pulse repetitions (approximately 100 kHz) are reported. For a CuBr laser with a 8 mm diameter discharge tube the laser pulse repetition rate as high as 270 kHz was realized.

  3. Preparation and characterization of poly(glycidyl methacrylate)-grafted magnetic nanoparticles: Effects of the precursor concentration on polyol synthesis of Fe3O4 and [PMDETA]0/[CuBr2]0 ratios on SI-AGET ATRP

    Science.gov (United States)

    Jiang, Liping; Zhou, Xuyang; Wei, Guyun; Lu, Xiaoduo; Wei, Weiping; Qiu, Jianhua

    2015-12-01

    Polymer brushes based on poly(glycidyl methacrylate) (PGMA) have been successfully grafted from the surface of silica coated iron oxide (Fe3O4@SiO2) nanoparticles via surface-initiated activators generated by electron transfer atom transfer radical polymerization (SI-AGET ATRP). The size of the nanoparticles could be adjusted from 7.3 to 9.6 nm by varying the precursor concentration of iron(III) acetylacetonate. The Fe3O4 nanoparticles possessed a highly crystalline structure, and the saturation magnetization of the as-prepared magnetite was strongly related to the particle size. Furthermore, the grafted PGMA content on the magnetic nanoparticles could be controlled by varying the ligand to transition metal ratio in a N,N,N‧,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr2 catalyst system. The maximum grafted content was 23.1% at a ratio of [PMDETA]0/[CuBr2]0 = 2:1.

  4. Dinuclear Metallacycles with Single M-X-M Bridges (X = Cl(-), Br(-); M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)): Strong Antiferromagnetic Superexchange Interactions.

    Science.gov (United States)

    Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Wojciechowska, Agnieszka; Stoian, Sebastian A; Ozarowski, Andrew

    2017-03-06

    A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2](3+) (X = Cl(-), Br(-)) complexes have two ditopic bis(pyrazolyl)methane ligands bridging two metals in a metallacyclic arrangement. The fifth coordination site of the distorted trigonal bipyramidal metal centers is filled by a bridging halide ligand that has an unusual linear or nearly linear M-X-M angle. The NMR spectra of [Zn2(μ-Cl)(μ-Lm*)2](ClO4)3 and especially [Cd2(μ-Cl)(μ-Lm*)2](ClO4)3 demonstrate that the metallacycle structure is maintained in solution. Solid state magnetic susceptibility data for the copper(II) compounds show very strong antiferromagnetic exchange interactions, with -J values of 536 cm(-1) for [Cu2(μ-Cl)(μ-Lm)2](ClO4)3·xCH3CN, 720 cm(-1) for [Cu2(μ-Cl)(μ-Lm*)2](ClO4)3, and 945 cm(-1) for [Cu2(μ-Br)(μ-Lm*)2](ClO4)3·2CH3CN. Smaller but still substantial antiferromagnetic interactions are observed with other first row transition metals, with -J values of 98 cm(-1) for [Ni2(μ-Cl)(μ-Lm*)2](ClO4)3, 55 cm(-1) for [Co2(μ-Cl)(μ-Lm*)2](ClO4)3, and 34 cm(-1) for [Fe2(μ-Cl)(μ-Lm*)2](ClO4

  5. Photoinduced Br Desorption from CsBr Thin Films Grown on Cu(100)

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, Matthew T.; Joly, Alan G.; Hess, Wayne P.; Shluger, AL

    2015-10-22

    Thin films of CsBr deposited onto metals such as copper are potential photocathode materials for light sources and other applications. We investigate desorption dynamics of Br atoms from CsBr films grown on insulator (KBr, LiF) and metal (Cu) substrates induced by sub-bandgap 6.4 eV laser pulses. The experimental results demonstrate that the peak kinetic energy of Br atoms desorbed from CsBr/Cu films is much lower than that for the hyperthermal desorption from CsBr/LiF films. Kelvin probe measurements indicate negative charge at the surface following Br desorption from CsBr/Cu films. Our ab initio calculations of excitons at CsBr surfaces demonstrate that this behavior can be explained by an exciton model of desorption including electron trapping at the CsBr surface. Trapped negative charges reduce the energy of surface excitons available for Br desorption. We examine the electron-trapping characteristics of low-coordinated sites at the surface, in particular, divacancies and kink sites. We also provide a model of cation desorption caused by Franck-Hertz excitation of F centers at the surface in the course of irradiation of CsBr/Cu films. These results provide new insights into the mechanisms of photoinduced structural evolution of alkali halide films on metal substrates and activation of metal photocathodes coated with CsBr.

  6. UV-Induced Anisotropy In CdBr2-CdBr2: Cu Nanostructures

    Directory of Open Access Journals (Sweden)

    El-Naggar A. M.

    2015-09-01

    Full Text Available We have found an occurrence of anisotropy in the nanostructure CdBr2-CdBr2: Cu nanocrystalline films. The film thickness was varied from 4 nm up to 80 nm. The films were prepared by successive deposition of the novel layers onto the basic nanocrystals. The detection of anisotropy was performed by occurrence of anisotropy in the polarized light at 633 nm He-Ne laser wavelength. The occurrence of anisotropy was substantially dependent on the film thickness and the photoinduced power density. Possible mechanisms of the observed phenomena are discussed.

  7. Electrical conductivity studies on CuBr containing Al2O3 particles

    Science.gov (United States)

    Dubec, P. M.; Wagner, J. B., Jr.

    1984-01-01

    The conductivity of CuBr was studied and the role of a second phase, Al2O3, dispersed in CuBr was tested. CuBr melts at 493 C and exhibits three phases in the solid state. CuBr is a good ionic conductor with a transport number for copper ions of virtually unity with weighed proportions of the appropriate chemicals used. The CuBr materials were heated above melting point of CuBr, and the samples were sandwiched between copper electrodes. The ac conductivity, was determined at 1 kHz between 25 and 440 C depending on the sample. It was shown that at low temperatures, the conductivity for CuBr (Al2O3) increased by as much as 100, whereas in the beta phase the conductivity of CuBr containing Al2O3 decreased. The electrical conductivity studies are in agreement with earlier data.

  8. Electrochemical Behaviors of Fe2+ and Sm3+ in Urea-NaBr Low Temperature Melt and Their Inductive Codeposition

    Institute of Scientific and Technical Information of China (English)

    童叶翔; 刘鹏; 刘莉治; 杨绮琴

    2001-01-01

    The cyclic voltammetry, chronopotentiometry and chronoamperometry were used to study the behaviors of Fe2+ on Pt, Cu, Ag and Ti electrodes in urea-NaBr melt at 373 K. Electroreduction of Fe2+ to metallic Fe is irreversible in one step. The exchange current density determined on Ti electrode is 2.68×10-5 A·cm-2. Sm3+ does not reduce to Sm alone, but can be inductively codeposited with Fe2+. Sm-Fe alloy film contained over 90% Sm (mass fraction) can be obtained by potentiostatic electrolysis and galvanostatic electrolysis on Cu substrate. The Sm content in the alloy is related to the cathode potential, current density and the Sm3+/Fe2+ molar ratio. The surface state of the Sm-Fe deposit was studied by scanning electron microscopy.

  9. Coupled perpendicular magnetization in Fe/Cu/Fe trilayers

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, D. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany)]. E-mail: D.Repetto@fkf.mpg.de; Enders, A. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany); Kern, K. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany)

    2006-05-15

    Ultrathin epitaxial Fe films on Cu(1 0 0) with perpendicular magnetization have been used as templates for the preparation of FCC Fe/Cu/Fe trilayers. The magnetic anisotropy and the coupling of these films have been studied by in-situ magneto optical Kerr effect measurements and Kerr microscopy. The magnetic coupling of both Fe layers is found to be dominated by magnetostatic interaction. Adsorbate-induced spin reorientation in the top layer also causes spin reorientation in the bottom layer. The governing role of the Fe-vacuum interface for the magnetism of the whole trilayer is demonstrated.

  10. GMI in FeCuNbSiB/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Correa, M.A. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil)]. E-mail: mmacorrea@gmail.com; Viegas, A.D.C. [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Silva, R.B. da [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Andrade, A.M.H. de [Departamento de Fisica, CCNE, UFSM, 97105-900, Santa Maria, RS (Brazil); Sommer, R.L. [Centro Brasileiro de Pesquisas Fisicas, 22290-180, Rio de Janeiro, RJ (Brazil)

    2006-10-01

    Very high magnetoimpedance (MI) measured at frequencies up to 1.8 GHz in single and multilayered thin films with composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} and (Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9}+Cu) are reported. The magnetic properties of both systems are also compared. MI ratio as high as 300% for the multilayered samples were obtained.

  11. {[Cu2Br3]n[Cu(H-Leof)2]·2H2O} where Leof is Levofloxacin%{[Cu2Br3]n[Cu(H-Leof)2]·2H2O}(Leof是左氟沙星)

    Institute of Scientific and Technical Information of China (English)

    王锡森; 唐云志; 熊仁根

    2005-01-01

    The crystal structure of {[Cu2Br3]n[Cu(H-Leof)2]· 2H2O} (1) comprises of [Cu(H-Leof)2] + cations, [Cu2Br3]nanions and lattice water molecules. And anion is a 1-D chain formed through alternative Cu-Br dimer and triangular geometry. CCDC: 274841.

  12. Quantifying magnetic exchange in doubly-bridged Cu-X(2)-Cu (X = F, Cl, Br) chains enabled by solid state synthesis of CuF(2)(pyrazine).

    Science.gov (United States)

    Lapidus, Saul H; Manson, Jamie L; Liu, Junjie; Smith, Matthew J; Goddard, Paul; Bendix, Jesper; Topping, Craig V; Singleton, John; Dunmars, Cortney; Mitchell, J F; Schlueter, John A

    2013-05-04

    Solid state techniques involving pressure and temperature have been used to synthesize the fluoride member of the CuX(2)(pyrazine) (X = F, Cl, Br) family of coordination polymers that cannot be crystallized by solution methods. CuF(2)(pyrazine) exhibits unique trans doubly-bridged Cu-F(2)-Cu chains that provide an opportunity to quantify magnetic superexchange in an isostructural Cu-X(2)-Cu series.

  13. Thermodynamic Properties of Compressed CuX (X = Cl, Br) Compounds: Ab Initio Study

    Science.gov (United States)

    Bioud, Nadhira; Kassali, Kamel; Bouarissa, Nadir

    2017-04-01

    A pseudopotential plane wave method based on the density functional theory has been employed to study some thermodynamic properties of copper chloride (CuCl) and copper bromide (CuBr) compounds under the effect of temperature and pressure. The phase transition pressure, the unit cell volume, the isothermal bulk modulus, the constant volume heat capacity, the entropy, the Debye temperature, the Grüneisen parameter and the volumetric thermal expansion coefficient are studied in the pressure range 0-10 GPa, and for temperatures ranging from 0 K up to 650 K and 750 K for CuCl and CuBr, respectively. The phase transition pressure is found to be around 7.8 and 6.95 GPa for CuCI and CuBr, respectively. These values are respectively in reasonably good agreement with the experimental ones of 8.2 GPa and 6.8 GPa reported in the literature. Moreover, at room temperature and zero pressure, the heat capacity at constant volume and the Grüneisen parameter of both compounds of interest are found to be in good agreement with the available experimental and theoretical data. The information gathered from the present investigation may be useful for the study of the behavior of the fundamental properties of CuCI and CuBr under the influence of high temperature and pressure.

  14. Modeling of Output Characteristics of a UV Cu+ Ne-CuBr Laser

    Directory of Open Access Journals (Sweden)

    Snezhana Georgieva Gocheva-Ilieva

    2012-01-01

    Full Text Available This paper examines experiment data for a Ne-CuBr UV copper ion laser excited by longitudinal pulsed discharge emitting in multiline regime. The flexible multivariate adaptive regression splines (MARSs method has been used to develop nonparametric regression models describing the laser output power and service life of the devices. The models have been constructed as explicit functions of 9 basic input laser characteristics. The obtained models account for local nonlinearities of the relationships within the various multivariate subregions. The built best MARS models account for over 98% of data. The models are used to estimate the investigated output laser characteristics of existing UV lasers. The capabilities for using the models in predicting existing and future experiments have been demonstrated. Specific analyses have been presented comparing the models with actual experiments. The obtained results are applicable for guiding and planning the engineering experiment. The modeling methodology can be applied for a wide range of similar lasers and laser devices.

  15. [Oxidation of mercury by CuBr2 decomposition under controlled-release membrane catalysis condition].

    Science.gov (United States)

    Hu, Lin-Gang; Qu, Zan; Yan, Nai-Qiang; Guo, Yong-Fu; Xie, Jiang-Kun; Jia, Jin-Ping

    2014-02-01

    CuBr2 in the multi-porous ceramic membrane can release Br2 at high temperature, which was employed as the oxidant for Hg0 oxidation. Hg0 oxidation efficiency was studied by a membrane catalysis device. Meanwhile, a reaction and in situ monitoring device was designed to avoid the impact of Br2 on the downstream pipe. The result showed that the MnO(x)/alpha-Al2O3 catalysis membrane had a considerable "controlled-release" effect on Br2 produced by CuBr2 decomposition. The adsorption and reaction of Hg0 and Br2 on the surface of catalysis membrane obeyed the Langmuir-Hinshelwood mechanism. The removal efficiency of Hg0 increased with the rising of Br2 concentration. However, when Br2 reached a certain concentration, the removal efficiency was limited by adsorption rate and reaction rate of Hg0 and Br2 on the catalysis membrane. From 473 K to 573 K, the variation of Hg0 oxidation efficiency was relatively stable. SO2 in flue gas inhibited the oxidation of Hg0 while NO displayed no obvious effect.

  16. Hyperfine and magnetic properties of Fe-Cu clusters and Fe precipitates embedded in a Cu matrix

    Energy Technology Data Exchange (ETDEWEB)

    Klautau, A B [Faculdade de Fisica, Universidade Federal do Para, 66075-110, Belem, PA (Brazil); Socolovsky, L M [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires, C1063ACV, Buenos Aires (Argentina); Nogueira, R N [Faculdade Taboao da Serra, 06768-000, Taboao da Serra, SP (Brazil); Petrilli, H M, E-mail: aklautau@ufpa.b [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

    2009-12-16

    Using the first-principles real-space linear muffin-tin orbital method within the atomic sphere approximation (RS-LMTO-ASA) we study hyperfine and local magnetic properties of substituted pure Fe and Fe-Cu clusters in an fcc Cu matrix. Spin and orbital contributions to magnetic moments, hyperfine fields and the Moessbauer isomer shifts at the Fe sites in Fe precipitates and Fe-Cu alloy clusters of sizes up to 60 Fe atoms embedded in the Cu matrix are calculated and the influence of the local environment on these properties is discussed.

  17. Comparison of Microstructural and Morphological Properties of Electrodeposited Fe-Cu Thin Films with Low and High Fe : Cu Ratio

    Directory of Open Access Journals (Sweden)

    Umut Sarac

    2013-01-01

    Full Text Available Fe-Cu films with low and high Fe : Cu ratio have been produced from the electrolytes with different Fe ion concentrations at a constant deposition potential of −1400 mV versus saturated calomel electrode (SCE by electrodeposition technique onto indium tin oxide (ITO coated conducting glass substrates. It was observed that the variation of Fe ion concentration in the electrolyte had a very strong influence on the compositional, surface morphological, and microstructural properties of the Fe-Cu films. An increase in the Fe ion concentration within the plating bath increased the Fe content, consequently Fe : Cu ratio within the films. The crystallographic structure analysis showed that the Fe-Cu films had a mixture of face-centered cubic (fcc Cu and body centered cubic (bcc α-Fe phases. The average crystallite size decreased with the Fe ion concentration. The film electrodeposited from the electrolyte with low Fe ion concentration exhibited a morphology consisting of dendritic structures. However, the film morphology changed from dendritic structure to cauliflower-like structure at high Fe ion concentration. The surface roughness and grain size were found to decrease significantly with increasing Fe ion concentration in the electrolyte. The significant differences observed in the microstructural and morphological properties caused by the change of Fe ion concentration in the electrolyte were ascribed to the change of Fe : Cu ratio within the films.

  18. Structural and magnetic properties of epitaxial Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Y. E-mail: t5101008@iwate-u.ac.jp; Nakanishi, Y.; Yoshimoto, N.; Yamaguchi, A.; Nakamura, M.; Yoshizawa, M

    2004-05-01

    We have grown FCC-Fe/Cu multilayers by molecular beam epitaxy method. The structural and magnetic properties were studied by RHEED, XRD and magnetoresistance measurement (MR). The RHEED images confirmed that Fe/Cu multilayers were epitaxially grown on Cu(1 0 0). Furthermore, a clear negative MR was observed. The buffer layer condition for MR effect will be discussed.

  19. Preparation of magnetic recoverable nanosize Cu-Fe2O3/Fe photocatalysts.

    Science.gov (United States)

    Kang, Hsu-Ya; Wang, H Paul

    2013-07-02

    Iron based catalysts generally have the advantage of the easily operated magnetically recovery from application sites. In the present work, paramagnetic iron and copper core-shell nanoparticles having the iron fractions (X(Fe) = Fe/(Cu+Fe)) of 0.33-1.0 were prepared and characterized by in situ synchrotron X-ray absorption and scattering spectroscopy. During the temperature-programmed carbonization (TPC) of Cu(2+)- and Fe(3+)-β-cyclodextrin (CD) complexes, a rapid reduction of Cu(II) occurs at about 453 K together with a growth of the metallic copper (Cu). Iron proceeds in the distinct growth path. At 453-513 K, the Fe(III) → Fe(II) → Fe consecutive reduction is observed. The unreduced Fe(III) (7-13%) is coated on the surfaces of the Fe nanoparticles (as Fe2O3/Fe). Growth of the Fe nanoparticle is inhibited by the surface Fe2O3, while the steady growth in Cu is observed. The Cu has a size range of 14-18 nm in diameter, compared to the small Fe2O3/Fe ones (3-6 nm). Under the UV-visible light irradiation for four hours, methylene blue can be photocatalytically degraded (>90%) by the (Cu-Fe2O3/Fe)@C. The (Cu-Fe2O3/Fe)@C photocatalysts can effectively oxidize dye molecules, providing a promising alternative for dye degradation using solar energy. Recovery of the (Cu-Fe2O3/Fe)@C photocatalysts can be attained by applying external magnetic field to trap the ferromagnetic Cu-Fe2O3/Fe nanoparticles, which suggests an economically attractive process, especially applied in photocatalytic degradation of dye-contaminated wastewater.

  20. A Comparative Kinetics Study between Cu/SSZ-13 and Fe/SSZ-13 SCR Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Wang, Yilin; Kollar, Marton; Washton, Nancy M.; Szanyi, Janos; Peden, Charles HF

    2015-11-09

    Cu- and Fe/SSZ-13 catalysts with the same Cu(Fe)/Al ratios are synthesized using the same parent SSZ-13 starting material. The catalytic performance for both fresh and hydrothermally aged catalysts is tested with NO and NH3 oxidation, and standard SCR reactions under steady-state conditions, and standard and fast SCR under temperature-programmed conditions. For standard SCR, Cu/SSZ-13 shows much better low-temperature performance which can be explained by NH3-inhibition of Fe/SSZ-13. During hydrothermal aging, both catalysts undergo dealumination but Fe/SSZ-13 dealuminates more severely. For aged catalysts, Cu/SSZ-13 gains oxidation activities due to formation of CuOx. However, Fe/SSZ-13 loses oxidation activities although formation of FeOx clusters and FeAlOx species also occur. Because of such physical properties differences, aged Cu/SSZ-13 loses while Fe/SSZ-13 maintains high-temperature SCR selectivities. A physical mixture of aged catalysts provides stable SCR performance in a wide temperature range and is able to decrease N2O formation at high reaction temperatures. This suggests that Fe/SSZ-13 can be used as a cocatalyst for Cu/SSZ-13 for transportation applications. During temperature-programmed SCR reactions, weak hysteresis is found during standard SCR due to NH3 inhibition. For fast SCR, hysteresis caused by NH4NO3 inhibition is much more significant. NH4NO3 deposition is greatly enhanced by Brønsted and Lewis acidity of the catalysts.

  1. Heteropoly acid promoted Cu and Fe catalysts for the selective catalytic reduction of NO with ammonia

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Mossin, Susanne L.; Riisager, Anders

    2011-01-01

    Cu/TiO2, Fe/TiO2 and heteropoly acid promoted Cu/TiO2, Fe/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD, NH3-TPD, H2-TPR and EPR. The catalysts exhibited only crystalline TiO2 phases with the active metals and promoters in highly dispersed state. The acidic properties...... activity and acidity was lower for promoted catalysts than for unpromoted catalysts. In the heteropoly acid promoted catalysts the SCR active Cu and Fe metals were protected from potassium poisons by bonding of the potassium to the Brønsted acid centres. Thus heteropoly acid promoted catalysts might...... were studied and compared with the catalytic activity for the selective catalytic reduction (SCR) of NO with ammonia. The SCR activities and acidity values of heteropoly acid promoted catalysts were found to be much higher than unpromoted catalysts. The influence of potassium poisons on the SCR...

  2. Magnetic ordering in Fe/Co sandwiches on Cu(100).

    Science.gov (United States)

    Razee, S S A; Staunton, J B; Szunyogh, L

    2009-07-01

    We investigate magnetic correlations and local magnetic moments at finite temperatures of some Fe and Co multilayers on Cu(100) substrates, such as Co(m)Fe(n)Co(m)/Cu(100) and Fe(m)Co(n)Fe(m)/Cu(100). We use an ab initio mean-field theory of magnetic fluctuations for layered materials based on the first-principles local spin-density functional theory implemented through the screened Korringa-Kohn-Rostoker method. We find that the presence of Fe layers in the neighbourhood of a Co layer always leads to a reduction in the magnetic moment of the Co atoms, whereas that of the Fe atoms is enhanced. Of particular interest is the lack of local moment formation on the single fcc-Co layer sandwiched between two fcc-Fe layers. However, a Co layer completely immersed in a Cu environment remains ferromagnetic. The Curie temperature of the Co(m)Fe(n)Co(m)/Cu(100) system oscillates as the Fe layer thickness is increased whereas that of the Fe(m)Co(n)Fe(m)/Cu(100) system increases almost monotonically with Co layer thickness.

  3. Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

    Science.gov (United States)

    Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

    2011-12-01

    Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

  4. Magnetic dilution in the cadmium-doped spin ladder compound Cdx Cu1 - x (quinoxaline) Br2

    Science.gov (United States)

    Keith, Brian; Landee, Chris; Turnbull, Mark

    2011-03-01

    Both Cu (quinoxaline) (Br2) and Cu (quinoxaline) (Cl2) are examples of molecule-based magnets where the CuX4 dimers are linked into ladders by quinoxaline molecules, where X is either Cl or Br. The rung exchange occurs through the bridging halides while the rail exchange occurs through the quinoxaline rings. Introducing random rung interactions into the system [ Cu (quinoxaline) (Br2)1-x (Cl2)x ] has caused the spin gap to close, in contrast with the gapped pure spin ladder parents. Crystal growth of non-magnetic-doped molecular magnets, CdxCu1 - x (2 , 3 - dimethylpyrazine)Br2 , have been performed for several values of the nominal conentration, x, and have been confirmed. The magnetizations and susceptibilities of the magnetically diluted ladder assemblage are presented along with a comparison of the effects of dilution from the pure case (x=0).

  5. Superconducting spin-valve effect and triplet superconductivity in Co Ox/Fe1/Cu /Fe2/Cu /Pb multilayer

    Science.gov (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Kamashev, A. A.; Fominov, Ya. V.; Schumann, J.; Hess, C.; Kataev, V.; Büchner, B.; Garifullin, I. A.

    2015-06-01

    We report magnetic and superconducting properties of the modified spin-valve system CoOx/Fe1/Cu /Fe2/Cu /Pb . Introduction of a Cu interlayer between Fe2 and Pb layers prevents material interdiffusion process, increases the Fe2/Pb interface transparency, stabilizes and enhances properties of the system. This allowed us to perform a comprehensive study of such heterostructures and to present theoretical description of the superconducting spin-valve effect and of the manifestation of the long-range triplet component of the superconducting condensate.

  6. Effect of Fe Particle on the Surface Peeling in Cu-Fe-P Lead Frame

    Institute of Scientific and Technical Information of China (English)

    SU Juanhua; LIU Ping; DONG Qiming; LI Hejun; TIAN Baohong

    2006-01-01

    Under the surface peeling of Cu-Fe-P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dimension plane strain model and elastic-plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame alloy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress concentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of interface make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.

  7. Coordination variation of hydrated Cu2+/Br1- ions traversing the interfacial water in mesopores

    Science.gov (United States)

    Wang, Q.; Huang, X. F.; Li, C. X.; Pan, L. Q.; Wu, Z. H.; Hu, T. D.; Jiang, Z.; Huang, Y. Y.; Cao, Z. X.; Sun, G.; Lu, K. Q.

    2012-06-01

    Resolution of the atomistic and electronic details about the coordination structure variation of hydrated ions in the interfacial water is still a tough challenge, which is, however, essentially important for the understanding of ion adsorption, permeation and other similar processes in aqueous solutions. Here we report the tracing of coordination structure variation for hydrated Cu2+/Br1- ions traversing the interfacial water in Vycor mesopores (ϕ = 7.6 nm) by employing both X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopies. By controlled desorption/adsorption of water, the filling fraction of the mesopores, thus the water layer thickness, can be adjusted, which in turn effects the variation of coordination structure of the ions therein. It is found that both Cu2+ and Br1- ions prefer staying exclusively in the core water, and in this circumstance no ion pairs have been detected in the solution of concentrations up to 1.0 M. Following capillary decondensation occurring at a filling fraction of ˜35% which corresponds to a water layer of about three monolayers, Br1- ions begin immediately to reconstruct their first coordination shell, characterized by ionic dehydration, shrinkage of ion-water bond length, and formation of ion pairs. In contrast, Cu2+ ions can retain a bulk-like coordination structure till being driven to bond directly to the pore surface when the filling fraction is below 20%. At the final stage of dehydration via thermal vacuum treatment at 110°C, Cu2+ ions can be completely reduced to the Cu1+ state, and recover at room temperature only when the filling fraction is above 14%. These results may be inspirable for the investigation of similar problems concerning hydrated ions in water solution under different confining conditions.

  8. Coordination variation of hydrated Cu2+/Br1− ions traversing the interfacial water in mesopores

    Directory of Open Access Journals (Sweden)

    Q. Wang

    2012-06-01

    Full Text Available Resolution of the atomistic and electronic details about the coordination structure variation of hydrated ions in the interfacial water is still a tough challenge, which is, however, essentially important for the understanding of ion adsorption, permeation and other similar processes in aqueous solutions. Here we report the tracing of coordination structure variation for hydrated Cu2+/Br1- ions traversing the interfacial water in Vycor mesopores (ϕ = 7.6 nm by employing both X-ray absorption near edge structure and extended X-ray absorption fine structure spectroscopies. By controlled desorption/adsorption of water, the filling fraction of the mesopores, thus the water layer thickness, can be adjusted, which in turn effects the variation of coordination structure of the ions therein. It is found that both Cu2+ and Br1- ions prefer staying exclusively in the core water, and in this circumstance no ion pairs have been detected in the solution of concentrations up to 1.0 M. Following capillary decondensation occurring at a filling fraction of ∼35% which corresponds to a water layer of about three monolayers, Br1- ions begin immediately to reconstruct their first coordination shell, characterized by ionic dehydration, shrinkage of ion-water bond length, and formation of ion pairs. In contrast, Cu2+ ions can retain a bulk-like coordination structure till being driven to bond directly to the pore surface when the filling fraction is below 20%. At the final stage of dehydration via thermal vacuum treatment at 110°C, Cu2+ ions can be completely reduced to the Cu1+ state, and recover at room temperature only when the filling fraction is above 14%. These results may be inspirable for the investigation of similar problems concerning hydrated ions in water solution under different confining conditions.

  9. Determination of Cu/Zn and Fe in human serum of patients with sickle cell anemia using radiation synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Canellas, C.G.L. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Carvalho, S.M.F. [State Institute of Hematology Arthur de Siqueira Cavalcanti, 20.211-030 Rio de Janeiro (Brazil); Anjos, M.J. [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil); Physics Institute, State University of Rio de Janeiro, 20.559-900 Rio de Janeiro (Brazil); Lopes, R.T., E-mail: ricardo@lin.ufrj.br [Nuclear Instrumentation Laboratory, COPPE/UFRJ, P.O. Box 68509, 21.941-972 Rio de Janeiro (Brazil)

    2012-07-15

    In this work we analyzed serum samples from patients with Sickle Cell Anemia (SCA) using Total Reflection X-Ray Fluorescence using Synchrotron Radiation (SRTXRF). The SRTXRF measurements were performed at the X-Ray Fluorescence Beamline at the Brazilian National Synchrotron Light Laboratory (LNLS). We studied forty-three patients aged 18-50 suffering from SCA and sixty healthy volunteers aged 18-60. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Moreover, there are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. The concentrations of Fe and Cu in the serum samples of patients with SCA were larger, 120% and 20%, respectively, when compared with the CG. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples from patients suffering from SCA than from the CG. Therefore, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. - Highlights: Black-Right-Pointing-Pointer Serum samples from patients with Sickle Cell Anemia (SCA) were analyzed by SRTXRF. Black-Right-Pointing-Pointer It was possible to determine the concentrations of the P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Black-Right-Pointing-Pointer There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA process. Black-Right-Pointing-Pointer The results indicate that the Cu/Zn ratio can be used as an adjuvant index for diagnosis of SCA.

  10. Spin-current injection and detection in κ-(BEDT-TTF2Cu[N(CN2]Br

    Directory of Open Access Journals (Sweden)

    Z. Qiu

    2015-05-01

    Full Text Available Spin-current injection into an organic semiconductor κ-(BEDT-TTF2Cu[N(CN2]Br film induced by the spin pumping from an yttrium iron garnet (YIG film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF2Cu[N(CN2]Br film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF2Cu[N(CN2]Br. We found that the voltage signal in the κ-(BEDT-TTF2Cu[N(CN2]Br/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions.

  11. First principles calculations of interlayer exchange coupling in bcc Fe/Cu/Fe structures

    Energy Technology Data Exchange (ETDEWEB)

    Kowalewski, M.; Heninrich, B. [Simon Fraser Univ., Burnaby, British Columbia (Canada); Schulthess, T.C.; Butler, W.H. [Oak Ridge National Lab., TN (United States)

    1998-01-01

    The authors report on theoretical calculations of interlayer exchange coupling between two Fe layers separated by a modified Cu spacer. These calculations were motivated by experimental investigations of similar structures by the SFU group. The multilayer structures of interest have the general form: Fe/Cu(k)/Fe and Fe/Cu(m)/X(1)/Cu(n)/Fe where X indicates one AL (atomic layer) of foreign atoms X (Cr, Ag, or Fe) and k, m, n represent the number of atomic layers of Cu. The purpose of the experimental and theoretical work was to determine the effect of modifying the pure Cu spacer by replacing the central Cu atomic layer with the atomic layer of foreign atoms X. The first principles calculation were performed using the Layer Korringa-Kohn-Rostoker (LKKR) method. The theoretical thickness dependence of the exchange coupling between two semi-infinite Fe layers was calculated for pure Cu spacer thicknesses in the range of 0 < k < 16. The effect of the foreign atoms X on the exchange coupling was investigated using the structure with 9 AL Cu spacer as a reference sample. The calculated changes in the exchange coupling are in qualitative agreement with experiment.

  12. Magnetic properties of nanostructured CuFe2O4

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Goya, G.F.; Rechenberg, H.R.

    1999-01-01

    -energy ball milling in an open container with grain sizes ranging from 9 to 61 nm. Superparamagnetic relaxation effects have been observed in milled samples at room temperature by Mossbauer and magnetization measurements. At 15 K, the average hyperfine field of CuFe2O4 decreases with decreasing average grain......, approximately 20% enhancement of the saturation magnetization in CuFe2O4 nanoparticles was observed, which could be explained by a cation redistribution induced by milling. The high-field magnetization irreversibility and shift of the hysteresis loop detected in our samples have been assigned to a spin......The structural evolution and magnetic properties of nanostructured copper ferrite, CuFe2O4, have been investigated by X-ray diffraction, Mossbauer spectroscopy, and magnetization measurements. Nanometre-sized CuFe2O4 particles with a partially inverted spinel structure were synthesized by high...

  13. Preparation of 24Mg-Fe-Cu Target

    Institute of Scientific and Technical Information of China (English)

    FAN; Qi-wen; DU; Ying-hui; ZHANG; Rong

    2012-01-01

    <正>The three-layer-sandwich targets of 24Mg-Fe-Cu needed to be prepared in the physics experiment. The middle layers are thin ferromagnetic Fe layers of about 3.2 mg/cm2. The recoil stopper layers are thick crystallized and defect-free Cu layers of about 15 mg/cm2. The thickness of the 24Mg target layers is about 300 μg/cm2, and the uniformity should be better than 90%.

  14. Synthesis and Crystal Structure of [Cu(acac)(Hdmpz)3]Br·EtOH

    Institute of Scientific and Technical Information of China (English)

    LIU Jiu-Hui; ZHANG Quan-Zheng; HE Xiang; YU Ya-Qing; LU Can-Zhong

    2005-01-01

    The complex [Cu(C5H7O2)(C5H8N2)3]Br. C2H5OH was obtained from a reaction of CuBr, acac, and Hdmpz (Hdmpz = 3, 5-dimethylpyrazole) in a mixed solution of ethanol, ether and water. The crystal belongs to monoclinic system, space group P21/n with a = 8.101 (5), b = 19.264(10), c = 17.19(3) (A), β = 95.54(2)°, V = 2670(5) (A)3, Z = 4, Mr = 577.03, Dc = 1.435 g/cm3, F(000) = 1196, μ = 2.348 mm-1, R = 0.0500 and wR = 0.1188 for 5361 observed reflections (I > 2σ(Ⅰ)). The Cu(Ⅱ) ion is coordinated by three Hdmpz and one acac to form a distorted square-pyramid. The complex contains an ethanol molecule and a bromide anion outside acting as the counter ion.

  15. Lead-Free MA2CuCl(x)Br(4-x) Hybrid Perovskites.

    Science.gov (United States)

    Cortecchia, Daniele; Dewi, Herlina Arianita; Yin, Jun; Bruno, Annalisa; Chen, Shi; Baikie, Tom; Boix, Pablo P; Grätzel, Michael; Mhaisalkar, Subodh; Soci, Cesare; Mathews, Nripan

    2016-02-01

    Despite their extremely good performance in solar cells with efficiencies approaching 20% and the emerging application for light-emitting devices, organic-inorganic lead halide perovskites suffer from high content of toxic, polluting, and bioaccumulative Pb, which may eventually hamper their commercialization. Here, we present the synthesis of two-dimensional (2D) Cu-based hybrid perovskites and study their optoelectronic properties to investigate their potential application in solar cells and light-emitting devices, providing a new environmental-friendly alternative to Pb. The series (CH3NH3)2CuCl(x)Br(4-x) was studied in detail, with the role of Cl found to be essential for stabilization. By exploiting the additional Cu d-d transitions and appropriately tuning the Br/Cl ratio, which affects ligand-to-metal charge transfer transitions, the optical absorption in this series of compounds can be extended to the near-infrared for optimal spectral overlap with the solar irradiance. In situ formation of Cu(+) ions was found to be responsible for the green photoluminescence of this material set. Processing conditions for integrating Cu-based perovskites into photovoltaic device architectures, as well as the factors currently limiting photovoltaic performance, are discussed: among them, we identified the combination of low absorption coefficient and heavy mass of the holes as main limitations for the solar cell efficiency. To the best of our knowledge, this is the first demonstration of the potential of 2D copper perovskite as light harvesters and lays the foundation for further development of perovskite based on transition metals as alternative lead-free materials. Appropriate molecular design will be necessary to improve the material's properties and solar cell performance filling the gap with the state-of-the-art Pb-based perovskite devices.

  16. Superparamagnetism in CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grima-Gallardo, P.; Alvarado, F.; Munoz, M.; Duran, S.; Quintero, M.; Nieves, L.; Quintero, E.; Tovar, R.; Morocoima, M. [Centro de Estudios en Semiconductores (CES), Fac. Ciencias, Dpto. Fisica, Universidad de Los Andes, Merida (Venezuela); Ramos, M.A. [Laboratorio de Difraccion y Fluorescencia de Rayos-X, Instituto Zuliano de Investigaciones Tecnologicas (INZIT), La Canada de Urdaneta, Estado Zulia (Venezuela)

    2012-06-15

    The temperature dependencies of DC magnetic susceptibilities, {chi}(T), of CuFeInTe{sub 3} and CuFeGaTe{sub 3} alloys were measured in a SQUID apparatus using the protocol of field cooling (FC) and zero FC (ZFC). The FC curves of both samples reflect a weak ferromagnetic (or ferrimagnetic) behavior with a nearly constant value of {chi}(T) in the measured temperature range (2-300 K) indicating that the critical temperatures (T{sub c}) are >300 K. The ZFC curves diverges from FC, showing irreversibility temperatures (T{sub irr}) of {proportional_to}250 K for CuFeInTe{sub 3} and >300 K for CuFeGaTe{sub 3}, suggesting that we are dealing with cluster-glass systems in a superparamagnetic state. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Anomaly observed in Moessbauer spectra near the neel temperature of FeBr sub 2

    CERN Document Server

    Naili Di

    2003-01-01

    In several decades, iron(II) bromide (FeBr sub 2) has been investigated as a typical Ising-type antiferromagnet by several kinds of experimental techniques. By the Moessbauer measurements, it was normally observed that only the magnetic spectrum appeared just below Neel temperature in FeBr sub 2. However, we found the anomalous spectra, in which paramagnetic component coexisted with magnetic one near Neel temperature. For two kinds of single crystal FeBr sub 2 samples, IM and IIM, we determined the Moessbauer parameters of the observed spectra by the computer analyses: the relative absorption intensity I sub p of the paramagnetic component to the total absorption area of the best fitting spectrum and the value of the hyperfine field H sub h sub f of the magnetic component and values of the quadrupole splitting 1/2 centre dot e sup 2 qQ of the magnetic and the paramagnetic components. The temperature variation of H sub h sub f is unique and the same as that observed for the sample in which the anomaly was not ...

  18. Itinerant magnetism in metallic CuFe2Ge2.

    Science.gov (United States)

    Shanavas, K V; Singh, David J

    2015-01-01

    Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF) at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  19. Magnetic properties of nanocrystalline Fe-Cu-Si-B alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, Y; Ohta, M, E-mail: yoshihito_yoshizawa@hitachi-metals.co.j [Advanced Electronics Research Laboratory, Hitachi Metals, Ltd., 5200 Mikajiri, Kumagaya, Saitama 360-0843 (Japan)

    2009-01-01

    Recently, nanocrystalline Fe-Cu-B and Fe-Cu-Si-B soft magnetic alloys with high saturation magnetic flux density more than 1.8 T and low coercivity of about 6 A m{sup -1} were developed by annealing melt-quenched alloys containing 1.3 -1.5 at % Cu and 0 - 7 at % Si. In this work, the magnetic properties of annealed Fe{sub 77.5-x}Cu{sub x}Si{sub 15.5}B{sub 7} alloys with high Si content prepared by melt spinning are reported. The appropriate Cu content in this alloy system shifted to Cu content higher than that of the reported Fe-Cu-Si-B alloys with high B{sub s}. The annealed alloy with x = 2.0 showed the H{sub c} of about 10 A m{sup -1}, the B{sub 8000} of 1.47 T, and low magnetostriction of +4.8 x 10{sup -6}.

  20. Synthesis, Crystal Structure and Third-order Nonlinear Optical Properties of Nest-shaped Cluster [CuBr (bpy) 2 ] [MoOS3Cu3-Br2 (bpy)

    Institute of Scientific and Technical Information of China (English)

    宋瑛林; 侯红卫; 樊耀亭; 杜晨霞; 朱玉

    2001-01-01

    Nest-shaped cluster [CuBr(bpy)2][MoOS3Cu3Br2(bpy)] was synthesized by the treatment of (NH4)2MoO2S2,CuBr and Et4NBr with bpy (2,2'-bipyridyl) in CH3CN. Its structure has been characterized by X-ray diffraction:monoclinic,space group P21/n, with a=1.0092(4), b=2.6347(7), c =1.4087(3) nm, β = 91.744(9)°, V=3.7438 nm3, Z=4,and final R=0.051, Rw=0.053. It consists of two parts:nest-shaped structural unit [MoOS3Cu3Br2(bpy)]- and complex ion [CuBr(bpy)2]+. We determined its third-order nonlinear optical (NLO) properties with a 7-ns pulsed laser at 532 nm. The cluster exhibits strong NIO refractive behavior, its third-order susceptibility X(3) was calculated to be 2.7× 10-11esu in a 7.8×10-4 g/cm3 DMF solution.The value is comparable to those of inorganic clusters.

  1. Magnetic behaviour investigation on symmetric spin valves of Co/Cu/NiFe and NiFe/Cu/Co

    Institute of Scientific and Technical Information of China (English)

    李铁; 沈鸿烈

    2002-01-01

    In this paper, we have obtained and investigated the magnetic behaviours of the ferromagnetic layer in thesymmetric spin valves of Co/Cu/NiFe and NiFe/Cu/Co by measuring with a vibrating sample magnetometer andanalysing in terms of the multi-domain Ising models. It has been found that some magnetic layer can have quitedifferent magnetic behaviours in different structures of spin valves, depending on the properties of the under-layer. Inour investigation, we have found that the magnetic behaviour of a Co layer depends mainly on the magnetization of theunder-layer, whereas this is not the case for the NiFe layer.

  2. Effect of Cu surface segregation on the exchange coupling field of NiFe/FeMn bilayers

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The NiFe/FeMn bilayers with different buffer layers (Ta or Ta/Cu) were prepared by magnetron sputtering.Results show that the exchange coupling field of NiFe/FeMn films with Ta buffer is higher than that of the films with Ta/ Cu buffer. We analysed the reasons by investigating the crystallographic texture, surface roughness and surface segregation of both films, respectively. We found that the decrease of the exchange coupling fields of NiFe/FeMn films with Ta/Cu buffer layers was mainly caused by the Cu surface segregation on NiFe surface.

  3. Preparation and Properties of Amorphous NiFe/Cu/NiFe Thin Films

    Institute of Scientific and Technical Information of China (English)

    YE Yun; JIANG Ya-dong; HU Wen-cheng; ZENG Hong-juan

    2004-01-01

    The amorphous of Permalloy on the copper subtract was studied using composite electroplating method. A portion of hydrogen brings the counteraction on the surface of cathode leading nickel-iron alloys to be anomalous in the process of co-depositing. The results of X-ray diffraction (XRD) show that the Ni-Fe alloys layer is amorphous. The Giant Magneto -Impedance (GMI) effect of Ni-Fe alloys was obtained under the optimal conditions, dependence on the soft magnetic property of Ni-Fe amorphous thin film. As a result, the ratios△ Z/Z of NiFe/Cu/NiFe amorphous thin film are 30% at 40 kHz which is in low frequency. Furthermore, the GMI value of NiFe/Cu/NiFe amorphous thin film with a sandwich structure is higher than that of single-layer ferromagnetic films of the same thickness.

  4. In Situ Characterization of CuFe2O4 and Cu/Fe3O4 Water-Gas Shift Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Estrella, M.; Barrio, L; Zhou, G; Wang, X; Wang, Q; Wen, W; Hanson, J; Frenkel, A; Rodriguez, J

    2009-01-01

    Mixtures of copper and iron oxides are used as industrial catalysts for the water-gas shift (WGS, CO + H2O f H2 + CO2). In-situ time-resolved X-ray diffraction, X-ray absorption fine structure, and atomic pair distribution function analysis were used to study the reduction of CuFe2O4 with CO and the behavior of CuFe2O4 and Cu/Fe2O3 catalysts under WGS reaction conditions. MetalToxygenTmetal interactions enhance the stability of Cu 2+ and Fe 3+ in the CuFe2O4 lattice, and the mixed-metal oxide is much more difficult to reduce than CuO or Fe2O3. Furthermore, after heating mixtures of CuFe2O4/CuO in the presence of CO or CO/H2O, the cations of CuO migrate into octahedral sites of the CuFe2O4 lattice at temperatures (200-250 C) in which CuO is not stable. Above 250 C, copper leaves the oxide, the occupancy of the octahedral sites in CuFe2O4 decreases, and diffraction lines for metallic Cu appear. From 350 to 450 C, there is a massive reduction of CuFe2O4 with the formation of metallic Cu and Fe3O4. At this point, the sample becomes catalytically active for the production of H2 from the reaction of H2O with CO. Neutral Cu 0 (i.e., no Cu 1+ or Cu 2+ cations) is the active species in the catalysts, but interactions with the oxide support cannot be neglected. These studies illustrate the importance of in situ characterization when dealing with mixed-metal oxide WGS catalysts.

  5. In-situ Characterization of CuFe2O4 and Cu/Fe3O4 Water-Gas Shift Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez,J.A.; Estrella, M.; Barrio, L.; Zhou, G.; Wang, X.; Wang, Q.; Wen, W.; Hanson, J.C.; Frenkel, A.

    2009-08-13

    Mixtures of copper and iron oxides are used as industrial catalysts for the water-gas shift (WGS, CO + H2O → H2 + CO2). In-situ time-resolved X-ray diffraction, X-ray absorption fine structure, and atomic pair distribution function analysis were used to study the reduction of CuFe2O4 with CO and the behavior of CuFe2O4 and Cu/Fe2O3 catalysts under WGS reaction conditions. Metal↔oxygen↔metal interactions enhance the stability of Cu2+ and Fe3+ in the CuFe2O4 lattice, and the mixed-metal oxide is much more difficult to reduce than CuO or Fe2O3. Furthermore, after heating mixtures of CuFe2O4/CuO in the presence of CO or CO/H2O, the cations of CuO migrate into octahedral sites of the CuFe2O4 lattice at temperatures (200-250 oC) in which CuO is not stable. Above 250 oC, copper leaves the oxide, the occupancy of the octahedral sites in CuFe2O4 decreases, and diffraction lines for metallic Cu appear. From 350 to 450 oC, there is a massive reduction of CuFe2O4 with the formation of metallic Cu and Fe3O4. At this point, the sample becomes catalytically active for the production of H2 from the reaction of H2O with CO. Neutral Cu0 (i.e. no Cu+1 or Cu+2 cations) is the active species in the catalysts, but interactions with the oxide support are necessary in order to obtain high catalytic activity. These studies illustrate the importance of in-situ characterization when dealing with mixed-metal oxide WGS catalysts.

  6. Kinetic process of mechanical alloying in Fe50Cu50

    DEFF Research Database (Denmark)

    Huang, J.Y.; Jiang, Jianzhong; Yasuda, H.

    1998-01-01

    It is shown that mechanical alloying in the immiscible Fe-Cu system is governed by the atomic shear event and shear-induced diffusion process. We found that an alpha-to-gamma phase transformation, as evidenced by the Nishiyama-Wasserman orientation relationship, occurs by simultaneous shearing...... structures, until a complete fee Fe-Cu solid solution is formed. The results provide significant insight into the understanding of recent experiments showing that chemical mixing of immiscible elements can bd induced by mechanical alloying. [S0163-1829(98)51342-2]....

  7. Quantum-well states and induced magnetism in Fe/CuN/Fe bcc (001) trilayers

    DEFF Research Database (Denmark)

    Niklasson, A.M.N.; Mirbt, S.; Skriver, Hans Lomholt

    1996-01-01

    We have used a first-principles Green's function technique to investigate the formation of magnetic moments in Fe/Cu-N/Fe bcc (001) trilayers. We show that the magnetic moment in the paramagnetic spacer material to a first approximation may be described as a linear superposition of the magnetic...

  8. Visible-light-driven photocatalytic inactivation of Escherichia coli by magnetic Fe2O3-AgBr.

    Science.gov (United States)

    Ng, Tsz Wai; Zhang, Lisha; Liu, Jianshe; Huang, Guocheng; Wang, Wei; Wong, Po Keung

    2016-03-01

    Bacterial inactivation by magnetic photocatalyst receives increasing interests for the ease recovery and reuse of photocatalysts. This study investigated bacterial inactivation by a magnetic photocatalysts, Fe2O3-AgBr, under the irradiation of a commercially available light emitting diode lamp. The effects of different factors on the inactivation of Escherichia coli were also evaluated, in term of the efficiency in inactivation. The results showed that Fe2O3-AgBr was able to inactivate both Gram negative (E. coli) and Gram positive (Staphylococcus aureus) bacteria. Bacterial inactivation by Fe2O3-AgBr was more favorable under high temperature and alkaline pH. Presence of Ca(2+) promoted the bacterial inactivation while the presence of [Formula: see text] was inhibitory. The mechanisms of photocatalytic bacterial inactivation were systemically studied and the effects of the presence of various specific reactive species scavengers and argon suggest that Fe2O3-AgBr inactivate bacterial cells by the oxidation of H2O2 generated from the photo-generated electron and direct oxidation of photo-generated hole. The detection of different reactive species further supported the proposed mechanisms. The results provide information for the evaluation of bacterial inactivation performance of Fe2O3-AgBr under different conditions. More importantly, bacterial inactivation for five consecutive cycles demonstrated Fe2O3-AgBr exhibited highly stable bactericidal activity and suggest that the magnetic Fe2O3-AgBr has great potential for water disinfection.

  9. Properties of electrodeposited CoFe/Cu multilayers: The effect of Cu layer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Turgut, E-mail: stsahin4@hotmail.com [Deparment of Physics, Science and Literature Faculty, Balikesir University, 10100 Balikesir (Turkey); Kockar, Hakan, E-mail: hkockar@balikesir.edu.tr [Deparment of Physics, Science and Literature Faculty, Balikesir University, 10100 Balikesir (Turkey); Alper, Mursel, E-mail: malper@uludag.edu.tr [Deparment of Physics, Science and Literature Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey)

    2015-01-01

    CoFe/Cu multilayers were potentiostatically electrodeposited on Ti substrates as a function of different non-magnetic (Cu) layer thicknesses, and their characterizations were investigated. The compositional analysis performed by energy dispersive X-ray spectroscopy disclosed that the Cu content in the multilayers increased and the Co content decreased as non-magnetic layer was increased. However, the Fe content was almost stable. The scanning electron microscopy studies showed that the surface morphology of the films is strongly affected by the non-magnetic layer thickness, and X-ray diffraction was used to analyse the structural properties of the multilayers and revealed that the multilayers have face-centred cubic (fcc) structure and their preferred orientations change depending on the Cu layer thickness. In the case of magnetoresistance measurements of the multilayers performed at room temperature, the highest giant magnetoresistance (GMR) values exhibited for the films with the Cu layer thickness (6.0 nm) whereas the lowest GMR magnitudes were observed for the films without Cu layer. Therefore, the variations of the Cu layer thicknesses were observed to have a significant effect on the GMR of multilayers. The differences observed in the magnetotransport properties were attributed to the microstructural changes caused by the Cu layer thickness. - Highlights: • CoFe/Cu multilayers were potentiostatically electrodeposited on Ti substrates. • Microstructural and magnetoresistance properties of CoFe/Cu multilayers were investigated. • All films had a face-centred cubic structure irrespective of the multilayer content. • All samples exhibited GMR and the maximum GMR value was 11%.

  10. Reactions of Cu(I)Br with aziridine derivatives. Synthesis, characterization and crystal structures of monomeric, dimeric and hexameric aziridine (= az) complexes of the formal type [CuBr(az)2]n (n = 1, 2) and [CuBr(az)]6.

    Science.gov (United States)

    Bobka, Roman; Roedel, J Nicolas; Wirth, Stefan; Lorenz, Ingo-Peter

    2010-11-14

    The first syntheses of monomeric and oligomeric aziridine complexes of copper(I) are described. Cu(I)Br (1) reacts with a series of different aziridine derivatives (C(2)H(3)PhNH (2), C(2)H(2)Me(2)NH (3), C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2) (4)) to give the neutral dimeric complex [CuBr(C(2)H(3)PhNH)(2)](2) (5) and the ionic hexameric complex [Cu(6)Br(5)(C(2)H(2)Me(2)NH)(6)]Br (6) with terminal bound aziridine ligands as well as the neutral monomeric complex [CuBr(C(2)H(2)Me(2)NC(2)H(2)Me(2)NH(2))] (7) where the dimerized aziridine acts as a N,N'-chelating ligand. After purification, all of the complexes were fully characterized and their IR, (1)H and (13)C NMR spectra are reported and discussed. The single crystal structure analysis revealed distorted tetrahedral geometry for the copper(I) centres in the complexes 5 and 6 and a trigonal planar structure for complex 7. In the oligomers the copper centres are bridged by two μ(2)- (5) or two μ(3)- and three μ(4)-bromido ligands (6), respectively.

  11. Magnetic transitions in botallackite-structure Cu{sub 2}(OH){sub 3}Br and Cu{sub 2}(OH){sub 3}I

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, X.G., E-mail: zheng@cc.saga-u.ac.j [Department of Physics, Faculty of Science and Engineering, Saga University, Saga 840-8502 (Japan); Department of Physics, School of Engineering, Saga University, Saga 840-8502 (Japan); Yamashita, T.; Hagihala, M.; Fujihala, M. [Department of Physics, School of Engineering, Saga University, Saga 840-8502 (Japan); Kawae, T. [Department of Applied Quantum Physics, Faculty of Engineering, Kyushu University, Fukuoka 812-8581 (Japan)

    2009-04-15

    The deformed pyrochlore lattice compound clinoatacamite, Cu{sub 2}(OH){sub 3}Cl, shows intriguing magnetism and 1/4 substitution of Cu with nonmagnetic Zn leads to the two-dimensional kagome lattice ZnCu{sub 3}Cl{sub 2}(OH){sub 6} that exhibits spin liquid behaviour. These findings renewed interest in botallackite Cu{sub 2}(OH){sub 3}Cl, which is a polymorphous structure of clinoatacamite Cu{sub 2}(OH){sub 3}Cl possessing a two-dimensional triangular lattice. The present work investigates the effect of halogen ions on the magnetic transitions in the botallackite structure. Similar to the antiferromagnetic Cu{sub 2}(OH){sub 3}Cl (T{sub N}=7.2 K), Cu{sub 2}(OH){sub 3}Br and Cu{sub 2}(OH){sub 3}I both showed antiferromagnetic transitions at T{sub N}=10 and 14 K, respectively. Long-range order also exists in Cu{sub 2}(OH){sub 3}Br as exemplified by the muSR study. The experimental results suggest that the magnetic coupling on the triangular lattice is dominated by the super-exchange interaction through the halogen ions. Further detailed comparison studies on these botallackite-structure compounds are expected to clarify the spin configuration on this triangular lattice.

  12. Reduction of nitrobenzene by the catalyzed Fe/Cu process

    Institute of Scientific and Technical Information of China (English)

    XU Wenying; LI Ping; FAN Jinhong

    2008-01-01

    The polarization behavior of the couple Fe/Cu in 100 mg/L nitrobenzene aqueous solution was studied using Evans coupling diagrams. The results indicated that the iron corrosion was limited by both anodic and cathodic half-cell reactions under the neutral conditions and cathodically controlled under the alkaline conditions. Batch experiments were performed to study the effect of solution pH, reaction duration, concentration, type of electrolyte and dissolved oxygen (DO) on the reduction of nitrobenzene by the catalyzed Fe/Cu process. This process proved effective in the pH range of 3 to 11. The conversion efficiency of nitrobenzene at pH ≈ 10.1 was almost the same as that under highly acid conditions (pH ≈ 3). The degradation of nitrobenzene fell into two phases: adsorption and surface reduction, and the influence of adsorption and mass transfer became more extensive with solution concentration. The reduction rate decreased in the presence of DO in the solution, indicating that a need for aeration was eliminated in the catalyzed Fe/Cu process. Accordingly, spending on energy consumption would be reduced. Economic analysis indicated that merely 0.05 kg was required for the treatment of a ton of nitrobenzene-containing water with pH from 3 to 11. The catalyzed Fe/Cu process is cost-effective and of practical value.

  13. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.

    2009-01-01

    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly b...

  14. Spin-current injection and detection in κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Z., E-mail: qiuzy@imr.tohoku.ac.jp; Hou, D. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Uruichi, M. [Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585 (Japan); Uchida, K. [Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Yamamoto, H. M. [Research Center of Integrative Molecular Systems (CIMoS), Institute for Molecular Science, Okazaki 444-8585 (Japan); RIKEN, 2-1 Hirosawa, Wako 351-0198 (Japan); Saitoh, E. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan)

    2015-05-15

    Spin-current injection into an organic semiconductor κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br. We found that the voltage signal in the κ-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions.

  15. Time evolution of morphology in mechanically alloyed Fe-Cu

    KAUST Repository

    Wille, Catharina Gabriele

    2011-05-01

    Being widely accessible as well as already utilised in many applications, Fe-Cu acts as an ideal binary model alloy to elaborate the enforced nonequilibrium enhanced solubility in such a solution system that shows a limited regime of miscibility and characterised by a large positive heat of mixing. In addition to the detailed analysis of ball milled Fe-Cu powders by means of Atom Probe Tomography (APT), site specific structural analysis has been performed in this study using Transmission Electron Microscopy (TEM).In this contribution results on powders with low Cu concentrations (2.5-10 at%) are presented. Combining a ductile element (Cu, fcc) and a brittle one (Fe, bcc), striking differences in morphology were expected and found on all length-scales, depending on the mixing ratio of the two elements. However, not only could the atomic mixing of Fe and Cu be evaluated, but also the distribution of impurities, mostly stemming from the fabrication procedure. The combination of APT and TEM enables a correlation between the structural evolution and the chemical mixing during the milling process. For the first time, a clear distinction can be drawn between the morphological evolution at the surface and in the interior of the powder particles. This became possible owing to the site specific sample preparation of TEM lamellae by Focussed Ion Beam (FIB). Surprisingly, the texture arising from the ball milling process can directly be related to the classical rolling texture of cold rolled Fe. In addition, full homogeneity can be achieved even on the nano-scale for this material as shown by APT, resulting in an extended miscibility region in comparison to the equilibrium phase diagram. Grain sizes were determined by means of XRD and TEM. The strain corrected XRD results are in very good agreement with the values derived by TEM, both confirming a truly nanocrystalline structure. © 2011 Elsevier B.V.

  16. Itinerant magnetism in metallic CuFe2Ge2.

    Directory of Open Access Journals (Sweden)

    K V Shanavas

    Full Text Available Theoretical calculations are performed to understand the electronic structure and magnetic properties of CuFe2Ge2. The band structure reveals large electron density N(EF at the Fermi level suggesting a strong itinerant character of magnetism. The Fermi surface is dominated by two dimensional sheet like structures, with potentially strong nesting between them. The magnetic ground state appears to be ferromagnetic along a and antiferromagnetic in other directions. These results show that CuFe2Ge2 is an antiferromagnetic metal, with similarities to the Fe-based superconductors; such as magnetism with substantial itinerant character and coupling between magnetic order and electrons at the Fermi energy.

  17. Rapid solidification of Cu-Fe-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Baricco, M.; Bosco, E.; Acconciaioco, G.; Rizzi, P.; Coisson, M

    2004-07-15

    Cu{sub 80-x}Ni{sub x}Fe{sub 20} (x=0, 5 and 20) alloys have been rapidly solidified by planar flow casting. X-ray diffraction (XRD) analysis of as-quenched ribbons shows bcc-Fe precipitates embedded in an fcc phase (x=0), two co-existing fcc solid solutions (x=5) and a complete solid solution of the parent elements (x=20). Thermal treatments in the temperature range between 400 and 600 deg. C give precipitation and spinodal decomposition reactions. These phase transformations have been evidenced from a variation of lattice constants, from a broadening of diffraction peaks and from TEM observations. The role of Ni content on competition between precipitation and decomposition reactions during rapid solidification and annealing is discussed in terms of thermodynamic arguments. Recent CALPHAD assessment of thermodynamic properties for Cu-Fe-Ni system has been used for an estimation of composition and volume fraction of equilibrium phases.

  18. Magnetically Separable Fe3O4/AgBr Hybrid Materials: Highly Efficient Photocatalytic Activity and Good Stability

    Science.gov (United States)

    Cao, Yuhui; Li, Chen; Li, Junli; Li, Qiuye; Yang, Jianjun

    2015-06-01

    Magnetically separable Fe3O4/AgBr hybrid materials with highly efficient photocatalytic activity were prepared by the precipitation method. All of them exhibited much higher photocatalytic activity than the pure AgBr in photodegradation of methyl orange (MO) under visible light irradiation. When the loading amount of Fe3O4 was 0.5 %, the hybrid materials displayed the highest photocatalytic activity, and the degradation yield of MO reached 85 % within 12 min. Silver halide often suffers serious photo-corrosion, while the stability of the Fe3O4/AgBr hybrid materials improved apparently than the pure AgBr. Furthermore, depositing Fe3O4 onto the surface of AgBr could facilitate the electron transfer and thereby leading to the elevated photocatalytic activity. The morphology, phase structure, and optical properties of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-visible diffuse reflectance spectra (UV-vis DRS), and photoluminescence (PL) techniques.

  19. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  20. Exponentially decaying magnetic coupling in sputtered thin film FeNi/Cu/FeCo trilayers

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yajun, E-mail: yajun.wei@angstrom.uu.se; Akansel, Serkan; Thersleff, Thomas; Brucas, Rimantas; Lansaker, Pia; Leifer, Klaus; Svedlindh, Peter [Department of Engineering Sciences, Uppsala University, 75121 Uppsala (Sweden); Harward, Ian; Celinski, Zbigniew [Department of Physics, University of Colorado, Colorado Springs, Colorado 80918 (United States); Ranjbar, Mojtaba; Dumas, Randy K. [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Jana, Somnath; Pogoryelov, Yevgen; Karis, Olof [Department of Physics and Astronomy, Uppsala University, 75120 Uppsala (Sweden); Åkerman, Johan [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Department of Applied Physics and Microelectronics, Royal Institute of Technology, 10044 Kista (Sweden)

    2015-01-26

    Magnetic coupling in trilayer films of FeNi/Cu/FeCo deposited on Si/SiO{sub 2} substrates have been studied. While the thicknesses of the FeNi and FeCo layers were kept constant at 100 Å, the thickness of the Cu spacer was varied from 5 to 50 Å. Both hysteresis loop and ferromagnetic resonance results indicate that all films are ferromagnetically coupled. Micromagnetic simulations well reproduce the ferromagnetic resonance mode positions measured by experiments, enabling the extraction of the coupling constants. Films with a thin Cu spacer are found to be strongly coupled, with an effective coupling constant of 3 erg/cm{sup 2} for the sample with a 5 Å Cu spacer. The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel-Kasuya-Yosida and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant surprisingly decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. This is partially connected to the substantial interfacial roughness that washes away the oscillation. The results have implications on the design of multilayers for spintronic applications.

  1. Phase Transformations in Low-Fe Alloys of the Al-Cu-Fe System

    Institute of Scientific and Technical Information of China (English)

    Liming Zhang

    2004-01-01

    Microstructure and phase transformation in the Al-Cu-Fe alloys of the approximate compositional range of 20 -50 at.% Cu and 2 - 10 Fe at.% have been investigated from samples quenched from their respective temperatures by means of different thermal analysis, magnetothermal analysis, scanning electron microscopy, electron probe analysis and powder X-ray diffraction. Representative phase transformations categorized as polymorphic, discontinuous precipitation,quasi-binary eutectoid, and ternary transitional U-type phase transformation are presented. These phase transformations were found to have a common feature which consumes the β phase and appears the φ phase. A schematic diagram was proposed to demonstrate the transition processes with decreasing temperature.

  2. Ionothermal synthesis and structural characterization of [Cu(C4H6N2)4]Br2 and [Ni(C4H6N2)4]Br2

    Indian Academy of Sciences (India)

    Hong Wang; Bin Lu; Jingxiang Zhao; Qinghai Cai

    2015-07-01

    The ionothermal synthesis and spectroscopic, thermal and structural characterization of two new compounds [Cu(C4H6N2)4]Br2 (1) and [Ni(C4H6N2)4]Br2 (2) [(C4H6N2) = N-methylimidazole] are reported. In both 1 and 2, the central metal Cu (or Ni) ion adopts a square planar geometry and is bonded to the N-atoms of four terminal N-methylimidazole ligands.

  3. Photoluminescence characteristics of polariton condensation in a CuBr microcavity

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Masaaki, E-mail: nakayama@a-phys.eng.osaka-cu.ac.jp; Murakami, Katsuya; Furukawa, Yoshiaki; Kim, DaeGwi [Department of Applied Physics, Graduate School of Engineering, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan)

    2014-07-14

    We have investigated the photoluminescence (PL) properties of a CuBr microcavity at 10 K, including the temporal profiles, from the viewpoint of cavity-polariton condensation. The excitation energy density dependence of the PL intensity (band width) of the lower polariton branch at an in-plane wave vector of k{sub //} = 0 exhibits a threshold-like increase (decrease). A large blueshift in the PL energy of ∼10 meV caused by the cavity-polariton renormalization is correlated with the excitation energy density dependence of the PL intensity. The estimated density of photogenerated electron-hole pairs at the threshold is two orders lower than the Mott transition density. These results consistently demonstrate the occurrence of cavity-polariton condensation. In addition, we found that the PL rise and decay times are shortened dramatically by the cavity-polariton condensation, which reflects the bosonic final state stimulation in the relaxation process and the intrinsic cavity-polariton lifetime in the decay process.

  4. Mechanical alloying in the Fe-Cu system

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gente, C.; Bormann, R.

    1998-01-01

    in the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms...... for the preparation of materials under highly non-equilibrium conditions in systems with positive heats of mixing by mechanical alloying.......The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility...

  5. Giant Magnetoresistance Effect of [bcc-Fe(M)/Cu](M=Co,Ni)Multilayers

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    GMR effect of multilayers of bcc-Fe(M)(M=Co, Ni) alloy and Cu layers has been investigated. The maximum MR ratio is found at 1.1 nm Fe(Co) and 1.3~1.4 nm Cu layer thickness in [Fe(Co)/Cu], and at 1.6 nm Fe(Ni) and 1.4 nm Cu layer thickness in [Fe(Ni)/Cu]. Under the optimum annealing condition, the MR ratio increases up to 50% and 38% for Fe(Co) and Fe(Ni) systems, respectively. The origin of the increase of GMR is discussed, taking the progress of preferred orientation of Fe(Co)[100] or Fe(Ni)[100] by annealing into account.

  6. Ammonia synthesis on Au modified Fe(111) and Ag and Cu modified Fe(100) surfaces

    DEFF Research Database (Denmark)

    Lytken, Ole; Waltenburg, Hanne Neergaard; Chorkendorff, Ib

    2003-01-01

    In order to investigate any influence of steps and possible positive effects of making surface alloys the ammonia synthesis has been investigated over Au modified Fe(111) and Ag and Cu modified Fe(100) single crystals in the temperature range 603-773 K, using a system combining ultra-high vacuum...... and a high-pressure cell. Ammonia was synthesized from a stoichiometric (N-2:3H(2)) gas mixture at a pressure of 2 bar. By deposition of small amounts of An, the ammonia production activity of the Fe(1 1 1) surface can be enhanced. More important, for the gold modified surface, the reaction order in ammonia...

  7. Structures and energies of Cu clusters on Fe and Fe3C surfaces from density functional theory computation.

    Science.gov (United States)

    Tian, Xinxin; Wang, Tao; Yang, Yong; Li, Yong-Wang; Wang, Jianguo; Jiao, Haijun

    2014-12-28

    Spin-polarized density functional theory computations have been carried out to study the stable adsorption configurations of Cun (n = 1-7, 13) on Fe and Fe3C surfaces for understanding the initial stages of copper promotion in catalysis. At low coverage, two-dimensional aggregation is more preferred over dispersion and three-dimensional aggregation on the Fe(110) and Fe(100) surfaces as well as the metallic Fe3C(010) surfaces, while dispersion is more favorable over aggregation on the Fe(111) surface. On the Fe3C(001) and Fe3C(100) surfaces with exposed iron and carbon atoms, the adsorbed Cu atoms prefer dispersion at low coverage, while aggregation along the iron regions at high coverage. On the iron surfaces, the adsorption energies of Cun (n = 2-7) are highest on Fe(111), medium on Fe(100) and lowest on Fe(110). On the Fe3C surfaces, the adsorption energies of Cun (n = 1-3) are highest on Fe3C(100), medium on Fe3C(010) and lowest on Fe3C(001), while, for n = 4-7 and 13, Fe3C(010) has stronger adsorption than Fe3C(100). On the basis of their differences in electronegativity, the adsorbed Cu atoms can oxidize the metallic Fe(110), Fe(100) and Fe3C(010) surfaces and become negatively charged. On the Fe3C(001) and Fe3C(100) surfaces with exposed iron and carbon atoms, the adsorbed Cu atoms interacting with surface carbon atoms are oxidized and positively charged. Unlike the most stable Fe(110) and Fe3C(001) surfaces, where the Fe(110) surface has stronger Cu affinity than the Fe3C(001) surface, which is in agreement with the experimental finding, the less and least stable Fe3C(010) and Fe3C(100) surfaces have stronger Cu affinities than the Fe(110) and Fe(100) surfaces. Since less stable facets are not preferably formed thermodynamically, it is crucial to prepare such surfaces to explore Cu adsorption and promotion, and this provides challenges to surface sciences.

  8. Magneto-volume effects in Fe-Cu solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorria, P. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)]. E-mail: pgorria@uniovi.es; Martinez-Blanco, D. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Iglesias, R. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Palacios, S.L. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Perez, M.J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Blanco, J.A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Fernandez Barquin, L. [Departamento CITIMAC, F. Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Hernando, A. [Instituto de Magnetismo Aplicado, UCM-RENFE, 28230 Las Rozas, Madrid (Spain); Gonzalez, M.A. [Instituto de Ciencia de Materiales de Aragon, CSIC, 50009 Zaragoza (Spain); Institut Laue-Langevin, BP 156, F-38042 Grenoble Cedex 9 (France)

    2006-05-15

    The magnetic properties of Fe-Cu metastable solid solutions have been investigated by means of neutron diffraction and magnetisation measurements. These compounds exhibit ferromagnetic order with Curie temperatures above room temperature for concentrations beyond 40 at% in Fe. The magnetic moment at 5 K can reach values over 2 {mu} {sub B}, while the high field susceptibility is similar to that found in FCC-FeNi Invar alloys. These features together with the low values for the linear coefficient for thermal expansion in the ferromagnetic region suggest that magneto-volume anomalies, including Invar behaviour, play a major role in the magnetic properties of this system when the crystal structure is face centred cubic. Such behaviour could be explained using theoretical total-band energy calculations.

  9. Synchrotron X-Ray Study on Structures of Ni80Fe20/Cu Superlattices

    Institute of Scientific and Technical Information of China (English)

    XU Ming; LUO Guang-Ming; CHAI Chun-Lin; YANG Tao; MAI Zhen-Hong; LAI Wu-Yan; WU Zhong-Hua; WANG De-Wu

    2001-01-01

    We have shown that, in contrast to the results in the literature, the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element (Cu). The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak. Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices. Upon annealing, the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.

  10. Enhancement of spin-Seebeck effect by inserting ultra-thin Fe70Cu30 interlayer

    Science.gov (United States)

    Kikuchi, D.; Ishida, M.; Uchida, K.; Qiu, Z.; Murakami, T.; Saitoh, E.

    2015-02-01

    We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe70Cu30/BiY2Fe5O12 (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe70Cu30 interlayer. This enhancement decays sharply with increasing the Fe70Cu30 thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe70Cu30 interlayer. Combined with control experiments using Pt/Fe70Cu30 devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe70Cu30/BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

  11. Characterization of the metastable Cu-Fe nanoparticles prepared by the mechanical alloying route

    Directory of Open Access Journals (Sweden)

    Mahsa Barzegar Vishlaghi

    2014-12-01

    Full Text Available Although Cu and Fe are immiscible under equilibrium conditions, they can form supersaturated solid solutions by mechanical alloying. In this paper, nano-structured of the metastable Cu-Fe phase containing 10, 15, 20 and 25% wt Fe were synthesized by intensive ball milling for 15h, in order to achieve a solid solution of Fe in Cu. The phase composition, dissolution of the Fe atoms into the Cu matrix, and the morphology of the milling products were studied by X-ray Diffraction (XRD, Energy Dispersive Spectrometer (EDS, and Field Emission Scanning Electron Microscope (FESEM techniques, respectively. The mean crystallite size of the milled samples was determined by XRD peak broadening using the Williamson-Hall approximation. The XRD analysis results showed that the solid solubility of the Fe in the Cu was extended to 20%wt after milling for 15 h, and a homogeneous solid solution of Cu80Fe20 with a mean crystallite size of 19nm was obtained. The mean crystallite size decreased with increasing milling time and it was more evident in the initial stage of the milling. The Cu lattice parameter increased by dissolving the Fe into the Cu matrix probably due to the magneto-volume effect in the Cu-Fe alloys. The FESEM observations showed that the milling products were agglomerates consisting of uniform particles. The Vibrating Sample Magnetometer (VSM results showed that the Cu80Fe20 powder has soft magnetic properties.

  12. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    Science.gov (United States)

    Sirohi, Anshu; Singh, Chandan K.; Thakur, Gohil S.; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Haque, Zeba; Gupta, L. C.; Kabir, Mukul; Ganguli, Ashok K.; Sheet, Goutam

    2016-06-01

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (˜47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  13. Three novel Cu6S6 cluster-based coordination compounds: synthesis, framework modulation and the sensing of small molecules and Fe(3+) ions.

    Science.gov (United States)

    Song, Jiang-Feng; Li, Si-Zhe; Zhou, Rui-Sha; Shao, Jia; Qiu, Xiao-Min; Jia, Ying-Ying; Wang, Jun; Zhang, Xiao

    2016-08-01

    Three novel Cu6S6 cluster-based coordination compounds formulated as [Cu(mpymt)3]2 (1), {(CuBr4)[Cu(mpymt)6]}n (2), and {(CuI6)[Cu(mpymt)6]}n (3) (Hmpymt = 4-methylpyrimidine-2-thione), have been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 shows a distorted octahedral core of six copper atoms (Cu6S6) constructed from four α and two β type N[double bond, length as m-dash]C-SH parts from six mpymt(-) anions. Compound 2 displays an interesting 3D framework constructed from Cu6S6 and Cu4Br4 Cu(i) clusters simultaneously, interestingly, six mpymt(-) with α type N[double bond, length as m-dash]C-SH parts are involved in the formation of Cu6S6. Compound 3 displays an infinite 1D framework constructed from Cu6S6 and Cu6I6 Cu(i) clusters, notably, four α and two β type N[double bond, length as m-dash]C-SH parts are involved in the formation of the Cu6S6 cluster, however, only mpymt(-) ligands containing α type N[double bond, length as m-dash]C-SH parts form the bridged Cu6I6 cluster. The experimental results reveal that halogen ions finely modulate the structural features of compounds 1-3. The fluorescent properties of compounds 1-3 in the solid state and in various solvent emulsions were investigated in detail, the results of which indicate that compounds 1-3 are all highly sensitive naked eye colorimetric sensors for NB, 2-NT and Fe(3+) (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

  14. CuFe2 O4 -CuO Nanocomposites as Promising Materials for Solar Hydrogen Generation

    Science.gov (United States)

    Razavi, Mehdi; Amrollahi, Pouya; Yazdimamaghani, Mostafa; Tayebi, Lobat; Vashaee, Daryoosh

    2014-03-01

    Currently, hydrogen is produced, almost exclusively, by waterelectrolysis. This method can take advantage of economies of scale and most established techniques of producing hydrogen. We developed a nanocomposite material system composed of CuFe2O4 and CuO semiconductor particles to produce hydrogen by electrolysis of water. The nanocomposite powder was prepared using the sol-gel method. Techniques of X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy, transmission electron microscopy and UV diffuse reflectance analysis were employed to characterize the synthesized products.The results confirmed the formation of CuFe2O4-CuO nanocomposite powder. The hydrogen evolution was successfully observed over the new hetero-system of CuFe2O4-CuO. The electrolysis activity depended on the concentration of CuO in the system. In order to enhance the hydrogen production, we further optimized the composite material versus the concentration of the compounds.

  15. Ultrafast demagnetization, spin-dependent Seebeck effect, and thermal spin transfer torque in Pt/TbFe/Cu and Pt/TbFe/Cu/Fe thin films

    Science.gov (United States)

    Kimling, Johannes; Hebler, Birgit; Kimling, Judith; Albrecht, Manfred; Cahill, David G.

    We investigate diffusive spin currents in Pt(20nm)/TbFe(10nm)/Cu(100nm) and Pt(20 nm)/TbFe(10nm)/ Cu(100nm)/Fe(3nm) stacks using time-resolved magneto-optic Kerr effect (TRMOKE) and time-domain thermoreflectance measurements. Our experiments are based on two hypothesis: (1) fast changes of magnetization due to laser excitation are transferred into spin accumulation, e.g., via electron-magnon scattering; the generated spin accumulation drives a diffusive spin current into adjacent normal metal layers; (2) electronic thermal transport through the ferromagnetic layer injects a spin current into adjacent normal metal layers, based on the spin-dependent Seebeck effect. We excite the Pt layer with ps-laser pulses. Resulting diffusive spin currents generate nonequilibrium magnetization in the Cu layer (sample I) and induce a precession of the magnetization of the Fe layer via spin transfer torque (sample II). Both responses are probed using TRMOKE. Prior experiments used [Co(0.2nm)/Pt(0.4nm)]x5/Co(0.2nm) instead of TbFe. The ferrimagnetic TbFe layer with introduces two major modifications: (1) slow demagnetization behavior, and (2) large thermal resistance. Hence, thermal spin transfer torques can be observed on significantly longer time scales. Financial support by the German Research Foundation under DFG-Grant No. KI 1893/1-1 and DFG-Grant No. AL 618/21-1 are kindly acknowledged.

  16. Evaluation of Fe and Zn/Cu ratio in serum of patients with sickle cell anemia by total reflection X-ray fluorescence using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Canellas, Catarine G.L.; Leitao, Roberta G.; Lopes, Ricardo T., E-mail: catarine@lin.ufrj.b, E-mail: ricardo@lin.ufrj.b [Universidade Federal do Rio de Janeiro (PEN/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Engenharia Nuclear. Lab. de Instrumentaco Nuclear; Carvalho, Silvia M.F., E-mail: silvia@hemorio.rj.gov.b [State Institute of Hematology Arthur de Siqueira Cavalcanti (HEMORIO), Rio de Janeiro, RJ (Brazil); Bellido, Alfredo Victor B., E-mail: alfredo@ien.gov.b [Federal Fluminense University (UFF), Niteroi, RJ (Brazil). Chemistry Inst.; Anjos, Marcelino J., E-mail: marcelin@lin.ufrj.b [State University of Rio de Janeiro (UERJ), RJ (Brazil). Physics Inst.

    2011-07-01

    Sickle cell anemia (SCA) is a blood disorder that affects hemoglobin, the protein found in red blood cells that help carry oxygen throughout the body. In this work we have analyzed serum samples from patients with SCA by using total reflection X-ray fluorescence using synchrotron radiation (SRTXRF). The SRTXRF measurements were performed at the X-ray fluorescence beamline at Brazilian National Synchrotron Light Laboratory (LNLS), in Campinas, Sao Paulo using a polychromatic beam. We have studied forty-three patients aged 18-50 years old, suffering from SCA and Sixty healthy volunteers aged 18-60 years old. It was possible to determine the concentrations of the following elements: P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Rb. Student's t-test was applied in order to check whether the two populations (CG x SCA) had the same mean values. It was observed that elemental concentration of P, Cl, K, Fe, Cu, Zn and Br differed significantly ({alpha} = 0.05) between groups of healthy subjects and SCA. The concentrations of K, Fe and Cu in the serum samples of patients with SCA were larger 15%, 120 % and 20 %, respectively, when compared with the CG. On the other hand, the concentrations of P (-20 %), Cl (-6 %), Zn (-25 %) and Br (-22 %) were smaller than the values determined for the control group. The serum level Cu/Zn ratio was significantly higher (60%) in the serum samples of patients with SCA group than the CG. So, the Cu/Zn ratio can be used as an adjuvant index in enhancement for diagnosis of SCA. There are evidences of an association among Fe, Cu, Zn and Cu/Zn in the SCA pathogenesis process. (author)

  17. Physical properties of the superconducting spin-valve Fe/Cu/Fe/In heterostructure

    Science.gov (United States)

    Leksin, P. V.; Garif'yanov, N. N.; Garifullin, I. A.; Schumann, J.; Kataev, V.; Schmidt, O. G.; Büchner, B.

    2012-01-01

    We report on structural, magnetic, and superconducting properties of the spin-valve multilayer system CoOx/Fe1/Cu/Fe2/In. For most of the thicknesses of the second iron layer dFe2 up to 2 nm, we have observed a full spin-valve effect for the superconducting current, i.e., a complete transition from the normal to the superconducting state by changing the mutual orientation of the magnetizations of the Fe1 and Fe2 layers. For dFe2<1 nm, the superconducting transition temperature TcP for the parallel orientation of magnetizations of the Fe1 and Fe2 layers is smaller than that for the antiparallel orientation TcAP, which corresponds to the direct spin-valve effect. For dFe2⩾1 nm, we have found the inverse spin-valve effect with ΔTc=TcAP-TcP<0. Further, in samples with a fixed thickness of the In layer, we have observed an oscillating dependence of its superconducting transition temperature Tc on dFe2. The analysis of the Tc(dFe2) dependence using the theory of the superconducting-ferromagnetic proximity effect has enabled determination of all microscopic parameters of the studied system. With these parameters, a satisfactory description of the sign-changing oscillating behavior of the spin-valve effect ΔTc(dFe2) has been obtained using a recent theory by Fominov [Ya. V. Fominov , Pis'ma Zh. Eksp. Teor. Fiz. 91, 329 (2010) [JETP Lett.JTPLA20021-364010.1134/S002136401006010X 91, 308 (2010)

  18. A route for recycling Nd from Nd-Fe-B magnets using Cu melts

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Martina; Gebert, Annett, E-mail: a.gebert@ifw-dresden.de; Stoica, Mihai; Uhlemann, Margitta; Löser, Wolfgang

    2015-10-25

    Phase evolutions in Nd-Fe-B magnet/Cu systems have been explored with regard to Nd recycling. It was demonstrated that large scale phase separation into a ferromagnetic Fe(B)-rich ingot core with α-Fe main phase and a non-magnetic (Cu,Nd)-rich ingot rim takes place upon arc melting with Cu fractions ≥ 21.5 wt.-%. The re-solidification of the Nd{sub 2}Fe{sub 14}B magnet main phase is suppressed. The rim consists of the Cu{sub 2}Nd main phase and CuNd/Cu{sub 4}Nd minority phases in which Al traces from the magnetic material are gathered. Induction melting of such Nd-Fe-B/Cu mixtures can support the separation of these phase regions with very sharp boundaries. Main features of liquid phase separation and microstructure evolution have been interpreted on the basis of Nd-Fe-Cu phase diagram data. The key advantage with respect to Nd recycling from Nd-Fe-B permanent magnet scrap is the substantial accumulation of Nd in the (Cu,Nd)-rich region of the phase separated solidified specimen, which can be easily detached from the Fe-rich part by mechanical-magnetic treatments. Such portions contained up to ∼44 wt.-% Nd (25 at.-%) in first lab-scale experiments. Nd recovery from the (Cu,Nd)-rich fractions is possible by exploiting the large chemical property differences between the reactive rare earths elements and Cu. - Highlights: • phase evolution analysis in Nd-Fe-B magnet/Cu systems with regard to Nd recycling. • Cu ≥ 21 wt.-%, large scale phase separation- Fe(B)-rich ingot core, (Cu,Nd)-rich rim. • high Nd content (∼44 wt.-%) of (Cu,Nd)-rich region, mechanical-magnetic treatments.

  19. Crystal structure and physical properties of (EDO-TTFBr{2)2}FeX{4 }(X = CI, Br)

    Science.gov (United States)

    Miyazaki, A.; Aimatsu, M.; Yamazaki, H.; Enoki, T.; Ugawa, K.; Ogura, E.; Kuwatani, Y.; Iyoda, M.

    2004-04-01

    The crystal structure and physical properties of radical ion salts (EDO-TTFBr{2})2FeX{4} (X = Cl, Br) composed of halogen-substituted organic donor and magnetic halide anions are investigated. The salts consist of uniformly stacked donor molecules, whose Br substituents are connected to halide ligands of anions with remarkably short intermolecular contacts. Both salts show metallic behavior above ca. 30K. The FeCl{4} salt shows an antiferromagnetic (AF) transition at TN = 4.2K despite the absence of anion\\cdot \\cdot \\cdot anion contacts, thus the magnetic interaction between the localized spins on the anions is mediated by the π -d interaction through the Br\\cdot \\cdot \\cdot Cl contacts. For the FeBr{4} salt the AF transition temperature is elevated to TN = 13.5K, accompanied with another anomaly at TC2 = 8.5K. This behavior can be qualitatively explained by a magnetic structure model where the π -d interaction between donor and anion is taken into account. Key words. Molecular conductors molecular magnets π -d interaction.

  20. Thermal Stability of CoFe/Cu/CoFe/IrMn Top Spin Valve

    Institute of Scientific and Technical Information of China (English)

    ZHOU Guang-Hong; WANG Yin-Gang; QI Xian-Jin

    2009-01-01

    We present a study of thermal stability of the top spin valve with a structure of seed Ta (5nm)/Co75Fe25 (5nm)/Cu (2.5nm)/Co75Fe25n (5nm)/Ir20 Mn80 (12nm)/cap Ta (8nm) deposited at room temperature by magnetron sputtering. A vibrating sample magnetometer fixed with a heater was used to record the magnetic hysteresis loops at variational temperatures and x-ray diffraction was performed to characterize the structure of the multilayer.The exchange field Hex and the coercivity of the pinned CoFe layer Hcp decrease monotonically with increasing temperature.The coercivity of the free CoFe layer Hcf in the spin valve shows a maximum at 498K.The temperature dependences of Hex,Hcp and Hcf have also been discussed.

  1. Nuclear Spin-Lattice Relaxation of {sup 82}BrFe

    Energy Technology Data Exchange (ETDEWEB)

    Tramm, C., E-mail: tramm@hiskp.uni-bonn.de; Eversheim, P. D.; Herzog, P. [Helmholtz-Institut fuer Strahlen-und Kernphysik der Universitaet Bonn (Germany)

    2004-12-15

    The field dependence of the nuclear spin-lattice relaxation (SLR) of cold implanted {sup 82}Br (T {<=} 25 mK) in {alpha}-Fe single crystals was investigated with nuclear magnetic resonance of oriented nuclei (NMR/ON) at low temperatures as experimental technique. The SLR at the lattice sites with the hyperfine fields found by earlier NMR/ON experiments was measured as a function of the applied external magnetic field B{sub ext} parallel to the three principle axes [100], [110] and [111] of the iron single crystal. The data were evaluated with the full relaxation formalism in the single impurity limit and for comparison also with the often employed model of a single exponential function with an effective relaxation time T{sub 1}'. With a phenomenological model the high field values of the relaxation rates r{sub {infinity},[100]'} = 6.6(2) . 10{sup -15} T{sup 2}sK{sup -1}, r{sub {infinity},[110]} = 5.4(2) . 10{sup -15} T{sup 2}sK{sup -1} and r{sub {infinity},[111]} 5.2(1) . 10{sup -15} T{sup 2}sK{sup -1} were obtained.

  2. Synthesis and magnetic properties of multilayer Ni/Cu and NiFe/Cu nanowires

    Indian Academy of Sciences (India)

    R S Liu; S C Chang; I Baginskiy; S F Hu; C Y Huang

    2006-07-01

    Highly ordered composite nanowires with multilayer Ni/Cu and NiFe/Cu have been fabricated by pulsed electrodeposition into nanoporous alumina membrane. The diameter of wires can be easily varied by pore size of alumina, ranging from 30 to 100 nm. The applied potential and the duration of each potential square pulse determine the thickness of the metal layers. The nanowires have been characterized by transmission electron microscopy (TEM), magnetic force microscopy (MFM), and vibrating sample magnetometer (VSM) measurements. The MFM images indicate that every ferromagnetic layer separated by Cu layer was present as single isolated domain-like magnet. This technique has potential use in the measurement and application of magnetic nanodevices.

  3. Induced effects of Cu underlayer on (111) orientation of Fe50 Mn50 thin films

    Institute of Scientific and Technical Information of China (English)

    WANG Lei; WANG Feng-ping; LIU Huan-ping; WU Ping; QIU Hong; PAN Li-qing

    2005-01-01

    Effects of Cu underlayer on the structure of Fe50 Mn50 films were studied. Samples with a structure of Fe50 Mn50 (200 nm)/Cu(tCu) were prepared by magnetron sputtering on thermally oxidized silicon substrates at room temperature. The thickness of Cu underlayer varied from 0 to 60 nm in the intervals of 10 nm. High-vacuum annealing treatments, at different temperatures of 200, 300 and 400 ℃ for 1 h, respectively, on the Fe50 Mn50 (200 nm)/Cu(20 nm) thin films were performed. The surface morphologies and textures of the samples were measured by field emission scan electronic microscope (FE-SEM) and X-ray diffraction(XRD). Energy dispersive X-ray spectroscopy (EDX) and Auger electron spectroscopy(AES) were used to analyze the compositional distribution. It is found that Cu underlayer has an obvious induce effect on (111) orientation of Fe50 Mn50 thin films. The induce effects of Cu on (111) orientation of Fe50 Mn50 changed with the increase of Cu layer thickness and the best effect was obtained at the Cu layer thickness of 20 nm. High-vacuum annealing treatments cause the migration of Mn atoms towards surface of the film and interface between Cu layer and substrate. With the increasing annealing temperature, migration of Mn atoms is more obvious, which leads to a Fe-riched Fe-Mn alloy film.

  4. The Fe-Cu system: A thermodynamic evaluation

    Science.gov (United States)

    Chen, Qing; Jin, Zhanpeng

    1995-02-01

    Thermochemical and phase diagram data in the Fe-Cu system have been critically evaluated by using phenomenological models for the Gibbs energy of various phases. A set of thermodynamic parameters more consistent with most of the selected experimental data than previous assess-ments has been obtained by a computerized least-squares method. Stable and metastable phase equilibria, T 0 curves, and thermodynamic properties are calculated with the optimized param-eters. The calculated liquid/face-centered cubic (fcc) T 0 curve and metastable liquid spinodal seem to permit an accurate prediction of maximum solid solubility obtained upon melt quenching in this system.

  5. Magnetization reversal of Fe ultrathin film on Cu (100)

    Institute of Scientific and Technical Information of China (English)

    He Wei; Zhan Qing-Feng; Wang De-Yong; Chen Li-Jun; Cheng Zhao-Hua

    2008-01-01

    The magnetization reversal of Fe/Cu(100) ultrathin films grown at room temperature is investigated by using an in situ magneto-optical Kerr effect polarimcter with a magnet that can rotate in a plane of incidence.There occur spin reorientation transitions from out-of-plane to in-plane magnetizations in 8 and 12 monolayers (ML) thick iron films.The coercive fields axe observed to be proportional to the reciprocal of the cosine with respect to the easy axis,suggesting that the domain-wall displacement plays a main role in the magnetization reversal process.

  6. Compressibility of nanostructured Fe-Cu materials prepared by mechanical milling

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J.S.; Gerward, Leif

    1999-01-01

    The compressibility of nanostructured Fe-Cu materials prepared by mechanical milling has been investigated by in-situ high-pressure x-ray diffraction using synchrotron radiation. It is found that the bulk modulus of both fcc-Cu and bcc-Fe phases decreases with decreasing grain sizes. The unstable...... ferromagnetic fcc-FeCu solid solution prepared by mechanical alloying has a bulk modulus of about 85 GPa, which is much smaller than the corresponding values for bulk fcc-Cu and bcc-Fe....

  7. FINITE ELEMENT ANALYSIS ABOUT STRESS AND STRAIN OF SURFACE PEELING IN Cu-Fe-P SHEET

    Institute of Scientific and Technical Information of China (English)

    Su Juanhua; Li Hejun; Dong Qiming; Liu Ping; Kang Buxi

    2005-01-01

    The microstructure of surface peeling in finish rolled Cu-0.1Fe-0.03P sheet is analyzed by scanning electron microscope and energy dispersive spectroscope. Fe-rich areas of different contents are observed in the matrix. The stress distributions and strain characteristics at the interface between Cu matrix and Fe particle are studied by elastic-plastic finite element plane strain model. Larger Fe particles and higher deforming extent of finish rolling are attributed to the intense stress gradient and significant non-homogeneity equivalent strain at the interface and accelerate surface peeling of Cu-0.1Fe-0.03P lead frame sheet.

  8. Aqueous copper-mediated living polymerization: exploiting rapid disproportionation of CuBr with Me6TREN.

    Science.gov (United States)

    Zhang, Qiang; Wilson, Paul; Li, Zaidong; McHale, Ronan; Godfrey, Jamie; Anastasaki, Athina; Waldron, Christopher; Haddleton, David M

    2013-05-15

    A new approach to perform single-electron transfer living radical polymerization (SET-LRP) in water is described. The key step in this process is to allow full disproportionation of CuBr/Me6TREN (TREN = tris(dimethylamino)ethyl amine to Cu(0) powder and CuBr2 in water prior to addition of both monomer and initiator. This provides an extremely powerful tool for the synthesis of functional water-soluble polymers with controlled chain length and narrow molecular weight distributions (polydispersity index approximately 1.10), including poly(N-isopropylacrylamide), N,N-dimethylacrylamide, poly(ethylene glycol) acrylate, 2-hydroxyethyl acrylate (HEA), and an acrylamido glyco monomer. The polymerizations are performed at or below ambient temperature with quantitative conversions attained in minutes. Polymers have high chain end fidelity capable of undergoing chain extensions to full conversion or multiblock copolymerization via iterative monomer addition after full conversion. Activator generated by electron transfer atom transfer radical polymerization of N-isopropylacrylamide in water was also conducted as a comparison with the SET-LRP system. This shows that the addition sequence of l-ascorbic acid is crucial in determining the onset of disproportionation, or otherwise. Finally, this robust technique was applied to polymerizations under biologically relevant conditions (PBS buffer) and a complex ethanol/water mixture (tequila).

  9. Magnetic Properties and Nanostructures of FePtCu:C Thin Films with FePt Underlayers

    Institute of Scientific and Technical Information of China (English)

    JIN Ling-Fang; YAN Ming-Lang

    2007-01-01

    Magnetic properties and nanostructures of FePtCu:C thin films with FePt underlayers (ULs) are studied. The effect of FePt ULs on the orientation and magnetic properties of the thin films are investigated by adjusting FePt UL thicknesses from 2nm to 14nm. X-ray diffraction (XRD) scans reveal that the orientation of the films is dependent on FePt UL thickness. For a 5-nm FePtCu:C nanocomposite thin film with a 2-nm FePt UL, the coercivity is 6.5 KOe, the correlation length is 59nm, the desired face-centred-tetragonal (fct) ordered structure [L10 phase] is formed and the c axis normal to the film plane [(001) texture] is obtained. These results indicate that the better orientation and magnetic properties of the films can be tuned by decreasing the thickness of the FePt UL.

  10. Study on Two-phase Nanocrystalline Nd8.5Fe74Co5Cu1NblZr3Cr1B6.5 Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    Jiansen NI; Hui XU; Mingyuan ZHU; Qiang LI; Bangxin ZHOU; Yuanda DONG

    2004-01-01

    Nd8.5Fe74Co5Cu1Nb1Zr3Cr1B6.5 bonded magnets were prepared by melt-spun and subsequent heat treatment. Magnetic properties of Br=0.68 T, JHc=716 Ka/m, (BH)max=77 Kj/m3 were achieved. The addition of Cr element shows to be significantly advantageous in reducing grain size and increasing the intrinsic coercivity.

  11. Two Liquid Phases Separation of Fe-Cu-B and Fe-Cu-Ag-B systems at 1873 and 1523 K

    Science.gov (United States)

    Ono-Nakazato, Hideki; Yamaguchi, Katsuhiro; Agawa, Shingo; Taguchi, Kenji; Usui, Tateo

    In recycling of steel scraps, the accumulation of tramp element in steel has been one of serious problems. Because copper in steel causes hot-shortness, the copper content of steel scraps is strictly adjusted under the upper limiting value in steelmaking process. In addition, recycling of steel scrap is necessary for energy savings and to realize a recycling-oriented society. In the present study,it was found that addition of boron could separate a single liquid in Fe-Cu system into Fe-rich and Cu-rich phases. Equilibrium experiments in Fe-Cu-B ternary system at 1873 and 1523 K showed that the copper content in Fe-rich phase decreased to 4.3 mass%. Subsequently, equilibrium experiments in Fe-Cu-Ag-B system were carried out and the copper was observed to be distributed between Fe-B and Ag phases. The distribution ratio of [mass%Cu](in Ag) / [mass%Cu](in Fe) was about 6 at 1873 K, regardless of copper content. It was found that the copper content of iron could be decreased by using silver as the solvent.

  12. Interacting spin-1/2 tetrahedral system Cu2Te2O5X2 (X = Cl, Br)

    DEFF Research Database (Denmark)

    Jensen, Jens

    2009-01-01

    , 064422 (2006)]. The calculated excitation spectra show many similarities with the experimental neutron-scattering results. Close to a magnetic Bragg point at 2 K, the theory predicts the presence of a quasielastic phason mode and an inelastic amplitude mode at about 0.6 meV. This is in qualitative...... agreement with experimental observations of Prša et al., but the amplitude mode is observed at the much higher energy of about 2.5 meV. This discrepancy is puzzling since the tetrahedral Cu-spin system, in any other respect, behaves as a system of large local spins coupled with each other in a three......-dimensional fashion. Preliminary model calculations for the Cu2Te2O5Br2 system lead to the same conclusion. Udgivelsesdato: 7. Januar...

  13. Cu-induced localization in the Fe-based superconductor FeTe0.5Se0.5

    Science.gov (United States)

    Wen, Jinsheng; Xu, Zhijun; Zhang, Cheng; Matsuda, Masa; Sobolev, Oleg; Park, Jitae; Bourret, Edith; Lee, Dunghai; Li, Qiang; Gu, Genda; Xu, Guangyong; Tranquada, John; Birgeneau, Robert

    2013-03-01

    We report neutron scattering and resistivity results on the Cu-substitution effects in FeTe0.5Se0.5 with a Tc of ~15 K. With a 2 % Cu substitution, the Tc is reduced to 8 K, and for Fe0.9Cu0.1Te0.5Se0.5, it is not superconducting. In Fe0.9Cu0.1Te0.5Se0.5, the low-energy magnetic excitations around the in-plane wave vector (0.5, 0.5) is greatly enhanced. Upon heating, the magnetic scattering is weakened, which is different from the temperature dependences of the Cu-free and 2 % Cu-doped sample. The spectral weight reduction upon warming decreases with increasing energy in the 10 % Cu-doped sample. We take these as evidences that Cu drives the system towards localization, which is confirmed by our resistivity data. These observations probably explain why superconductivity is absent in the Cu-doped BaFe2As2 system and demonstrate the inadequacy of the rigid-band shift model on the substitution effects of the 3 d transition metals. The work is supported by the U.S. Department of Energy.

  14. Kinetic study of the annealing reactions in Cu-Ni-Fe alloys; Estudio cinetico de las reacciones de recocido en aleaciones de Cu-Ni-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Donoso, E.

    2014-07-01

    The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC) and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi{sub 3} phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi{sub 3} phase. (Author)

  15. Short-range Ferromagnetism in Alloy Ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    DEFF Research Database (Denmark)

    Thanh, P. Q.; Hoa, N. Q.; Chau, N.;

    2014-01-01

    We have studied the magnetic properties of two amorphous alloy ribbons Fe72Cr6Si4Nb5B12Ag1 (FCSNB-Ag) and Fe72Cr6Si4Nb5B12Cu1 (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic...

  16. Magneto-optical response of Cu/NiFe/Cu nanostructure under surface plasmon resonance

    Science.gov (United States)

    Mahmoodi, S.; Moradi, M.; Mohseni, S. M.

    2016-12-01

    In this paper, we present theoretical and experimental studies about the surface plasmon resonance effects on the magneto-optical activity of Cu/NiFe/Cu nanostructures as a function of layers thickness and light incident angle. Device fabrication was done by an oblique deposition technique with RF magnetron sputtering to carefully cover fine step thickness variation of all constituted layers. Angular dependent transverse Kerr response of samples was measured in the Kretschmann configuration at a fixed wavelength of 632 nm. At an optimum layer thickness and incident angle, significant amplification of the transverse Kerr effect was observed. Enhancement in the transverse Kerr effect can be realized by hybridization of surface plasmon excitation and cavity resonance in the plasmonic nanostructure. Experimental results were in qualitative agreement with modeling based on the 4×4 transfer matrix formalism.

  17. High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

    Directory of Open Access Journals (Sweden)

    Anabil Gayen

    2013-01-01

    Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

  18. On the concentration and separation of the trace-elements fe, cu, zn, mn, pb, mo and co : Paper chromatography

    NARCIS (Netherlands)

    Erkelens, P.C. van

    1961-01-01

    Paper chromatographic separations are described by which the minor constituents of biological ashes are separated either into: (Pb) - Mn - Co - (Pb) - Cu - Fe, Mo, Zn; or into: Cu, Mn, Co - Pb - Fe - Mo - Zn.

  19. Study of Microstructure and Magnetic Properties of Pr-Fe-B-Cu Permanent Magnets by Hot Deformation

    Institute of Scientific and Technical Information of China (English)

    陈秀云; 姜忠良; 高天明; 吴严; 杨昌平; 朱静

    2002-01-01

    The relationship between the microstructures and magnetic properties of rare earth cast permanent Pr-Fe-B-Cu alloys by hot deformation was studied. Fine and well-aligned column grains can be obtained by using a proper solidification mould with a high cooling rate. The soft magnetic phase α-Fe can be removed during proper annealing treatment. Hot pressing can produce the anisotropy and refine the grain size, so that the magnetic properties are greatly improved. The technique has the advantages of simple processing, low cost and high benefit, compared with the common sintering processing. Under the condition of the deformation temperature of 1073 K, 90% strain and strain rate of 40×10-3 s-1, the magnetic properties obtained are: Br=1.05 T, i Hc=955 kAm-1, (BH)max=207 kJ*m-3.

  20. Fe and Cu stable isotopes in archeological human bones and their relationship to sex.

    Science.gov (United States)

    Jaouen, Klervia; Balter, Vincent; Herrscher, Estelle; Lamboux, Aline; Telouk, Philippe; Albarède, Francis

    2012-07-01

    Accurate sex assignment of ancient human remains usually relies on the availability of coxal bones or well-preserved DNA. Iron (Fe) and copper (Cu) stable isotope compositions ((56)Fe/(54)Fe and (65)Cu/(63)Cu, respectively) were recently measured in modern human blood, and an unexpected result was the discovery of a (56)Fe-depletion and a (65)Cu-enrichment in men's blood compared to women's blood. Bones, being pervasively irrigated by blood, are expected to retain the (56)Fe/(54)Fe and (65)Cu/(63)Cu signature of blood, which in turn is useful for determining the sex of ancient bones. Here, we report the (56)Fe/(54)Fe, (65)Cu/(63)Cu, and (66)Zn/(64)Zn ratios from a suite of well-preserved phalanxes (n = 43) belonging to individuals buried in the 17th and 18th centuries at the necropolis of Saint-Laurent de Grenoble, France, and for which the sex was independently estimated from pelvic bone morphology. The metals were purified from the bone matrix by liquid chromatography on ion exchange resin and the isotope compositions were measured by multiple-collector inductively coupled plasma mass spectrometry. The results show that, as expected from literature data on blood, male bone iron is depleted in (56)Fe and enriched in (65)Cu relative to female. No sex difference is found in the (66)Zn/(64)Zn ratios of bone. The concentration and isotopic data show no evidence of soil contamination. Four samples of five (77%) can be assigned their correct sex, a result comparable to sex assignment using Fe and Cu isotopes in blood (81%). Isotopic analysis of metals may therefore represent a valid method of sex assignment applicable to incomplete human remains.

  1. Structure and magnetic properties of Ni/Cu/Fe/MgO(001) films.

    Science.gov (United States)

    Lauhoff, G; Vaz, C A F; Bland, J A C

    2009-04-15

    The structural and magnetic properties of thin Ni films grown on Cu/Fe/MgO(001) and Cu/MgO(001) buffer layers are investigated and compared to those grown on Cu/Si(001). The use of an Fe seed layer a few monolayers thick leads to the epitaxial growth of high surface quality Cu(001) buffer layers on MgO(001), while Cu growth on the bare MgO(001) substrate results in polycrystalline films. Magneto-optic Kerr effect magnetometry shows that Ni films grown on Cu/Fe/MgO(001) exhibit dominant perpendicular magnetic anisotropy up to ∼90 Å, which is similar to that of Ni films grown on Cu/Si(001). The polycrystalline Ni films also exhibit perpendicular magnetic remanence, but with a dominant in-plane magnetization component.

  2. Structure and magnetic properties of Ni/Cu/Fe/MgO(001) films

    Energy Technology Data Exchange (ETDEWEB)

    Lauhoff, G; Vaz, C A F; Bland, J A C [Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE (United Kingdom)], E-mail: georglauhoff@georglauhoff.com, E-mail: carlos.vaz@cantab.net

    2009-04-15

    The structural and magnetic properties of thin Ni films grown on Cu/Fe/MgO(001) and Cu/MgO(001) buffer layers are investigated and compared to those grown on Cu/Si(001). The use of an Fe seed layer a few monolayers thick leads to the epitaxial growth of high surface quality Cu(001) buffer layers on MgO(001), while Cu growth on the bare MgO(001) substrate results in polycrystalline films. Magneto-optic Kerr effect magnetometry shows that Ni films grown on Cu/Fe/MgO(001) exhibit dominant perpendicular magnetic anisotropy up to {approx}90 A, which is similar to that of Ni films grown on Cu/Si(001). The polycrystalline Ni films also exhibit perpendicular magnetic remanence, but with a dominant in-plane magnetization component.

  3. Friction behavior of Al-Cu-Fe-B polycrystalline quasicrystals

    Institute of Scientific and Technical Information of China (English)

    周细应; 李培耀; 罗军明; 钱士强; 童建华

    2004-01-01

    Dry sliding friction between the polycrystalline Al59 Cu25.5 Fe12.5 B3 quasicrystals(QCs) and coating of thediamond-like carbon(DLC) was carried out by self-made tribometer under different conditions. The influences of four parameters(temperature, sliding velocity, applied load, atmosphere) on friction of quasicrystal surface were studied. Microstructure of quasicrystal, morphology of worn surface, and wear debris were observed by scanning electron microscope(SEM). The results show that for QCs, the friction coefficient and the roughness of worn surface is influenced by the parameters, especially greatly by the temperature. With increasing the applied load and sliding velocity, the friction coefficient decreases. The dominant wear mechanism at 350 ℃ is delamination for QCs. The cracks forms on the worn surface during friction. Moreover, phase transformation is not observed on worn surface of QCs at 350 ℃.

  4. Stripe-to-bubble transition of magnetic domains at the spin reorientation of (Fe/Ni)/Cu/Ni/Cu(001)

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; Choi, J.; Won, C.; Wu, Y. Z.; Scholl, A.; Doran, A.; Hwang, Chanyong; Qiu, Z.

    2010-06-09

    Magnetic domain evolution at the spin reorientation transition (SRT) of (Fe/Ni)/Cu/Ni/Cu(001) is investigated using photoemission electron microscopy. While the (Fe/Ni) layer exhibits the SRT, the interlayer coupling of the perpendicularly magnetized Ni layer to the (Fe/Ni) layer serves as a virtual perpendicular magnetic field exerted on the (Fe/Ni) layer. We find that the perpendicular virtual magnetic field breaks the up-down symmetry of the (Fe/Ni) stripe domains to induce a net magnetization in the normal direction of the film. Moreover, as the virtual magnetic field increases to exceed a critical field, the stripe domain phase evolves into a bubble domain phase. Although the critical field depends on the Fe film thickness, we show that the area fraction of the minority domain exhibits a universal value that determines the stripe-to-bubble phase transition.

  5. Synthesis and Crystal Structure of a Copper(Ⅱ) Complex with a Tab-Tab Disulfide Ligand (Tab-Tab)[CuBr4] (Tab = Trimethylammoniumphenyl-4-thiolate)

    Institute of Scientific and Technical Information of China (English)

    TANG Xiao-Yan; CHEN Jin-Xiang; LANG Jian-Ping

    2006-01-01

    Reaction of CuBr2 with TabHPF6/Et3N in methanol followed by dissolving the resulting precipitate in hydrobromic acid yielded purple blocks of the title complex [Tab-Tab][CuBr4] 1 (C18H26CuBr4N2S2). 1 crystallizes in the monoclinic system, space group P21/n with a = 9.686(3),b = 19.257(5), c = 13.399(4) (A), β= 93.610(9)°, V= 2494.2(13) (A)3, Z= 4, Dc = 1.911 g/cm3, T=193(2) K, Mr = 717.71, F(000) = 1396, μ = 74.58 cm-1, S = 1.126, R = 0.0748 and wR = 0.1736 for 2921 observed reflections with I > 2σ(Ⅰ). The structure of 1 contains a discrete [CuBr4]2- dianion and a [Tab-Tab]2+ dication. In the dianion, the Cu atom is coordinated to four Br atoms forming a distorted tetrahedral coordination geometry. The bromides of the dianion interact with the H atoms of the phenyl and methyl groups of the dications to form a 1D hydrogen-bonded chain.

  6. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    DAI FuPing; CAO ChongDe; WEI BingBo

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two separated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respectively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) droplets with the same size.

  7. Phase separation and rapid solidification of liquid Cu60Fe30Co10 ternary peritectic alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The metastable liquid phase separation and rapid solidification of Cu60Fe30Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two sepa- rated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respec- tively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) drop- lets with the same size.

  8. A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

    Science.gov (United States)

    A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

  9. A Study of Two-Phase Nanocrystalline Nd8.5Fe75Co5Cu1Zr3Nb1B6.5 Permanent Magnet

    Institute of Scientific and Technical Information of China (English)

    倪建森; 徐晖; 朱明原; 李强; 周邦新; 董远达

    2003-01-01

    Nanocrystalline Nd8.5Fe75Co5Cu1Zr3Nb1B6.5 ribbons were prepared by melt-spun (18 m*s-1) and subsequent heat treatment (670 ℃/4 min). Excellent magnetic properties of the bonded magnet were achieved as follows: Br=0.68 T (6.8 kGs), JHc=620.3 kA*m-1(7.8 kOe), (BH)max=74 kJ*m-3 (9.3 MGOe). The results of TEM photomicrographs confirm that the appearance of α-Fe phase is earlier than that of Nd2Fe14B phase during crystallization process. The addition of Cu and Zr elements shows to be advantageous to the improvement of an intrinsic coercivity and squareness of hysteresis loop, as well as energy product.

  10. Giant Magneto-Impedance Effect in Sandwiched FeSiB/Cu/FeSiB Films

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong; YANG Chun-Sheng; YU Jin-Qiang; ZHAO Xiao-Lin; MAO Hai-Ping

    2000-01-01

    Giant magneto-impedance (GMI) effect has been realized in the sandwiched FeSiB/Cu/FeSiB films. With magnetic field Ha and ac current applied along the longitudinal direction of the sample, the GMI ratio increases with the increasing Ha, reaching a positive maximum, value, and then decreases to negative values with further increase of magnetic field. Field dependence of the GMI ratio also indicates that the magnetic field corresponding to the maximum GMI ratio is different for various frequencies. The positive maximum GMI ratio is 17.2% for Ha=1600 A/m and frequency of 3 MHz. In addition, the films display a large negative GMI ratio with a magnetic field applied along the transverse direction and the value of the GMI ratio is about -13.4% for Ha=5600A/m and frequency of 3 MHz.

  11. Template-grown NiFe/Cu/NiFe nanowires for spin transfer devices

    DEFF Research Database (Denmark)

    Piraux, L.; Renard, K.; Guillemet, R.;

    2007-01-01

    We have developed a new reliable method combining template synthesis and nanolithography-based contacting technique to elaborate current perpendicular-to-plane giant magnetoresistance spin valve nanowires, which are very promising for the exploration of electrical spin transfer phenomena....... The method allows the electrical connection of one single nanowire in a large assembly of wires embedded in anodic porous alumina supported on Si substrate with diameters and periodicities to be controllable to a large extent. Both magnetic excitations and switching phenomena driven by a spin......-polarized current were clearly demonstrated in our electrodeposited NiFe/Cu/ NiFe trilayer nanowires. This novel approach promises to be of strong interest for subsequent fabrication of phase-locked arrays of spin transfer nano-oscillators with increased output power for microwave applications. © 2007 American...

  12. Tunable Magnetic Properties in CuCr2- x Fe x O4 Ceramics by Doping of Fe

    Science.gov (United States)

    Zhu, C. M.; Wang, L. G.; Bao, D. L. G. C.; Luo, H.; Tian, Z. M.; Yuan, S. L.

    2016-08-01

    CuCr2- x Fe x O4 ceramics have been successfully synthesized using the sol-gel method for the first time. With pure formation, material structure has been characterized by x-ray diffraction. The samples have been identified as having the spinel structure with formulae CuCr2- x Fe x O4. Micrographs obtained by scanning electron microscopy show the dense microstructure of the samples. The stoichiometric ratio of the ceramics has been measured through energy dispersive spectra. Magnetic properties of CuCr2- x Fe x O4 ceramics have been discussed. Temperature dependence of magnetization presents the gradually increasing irreversible temperature as the content of Fe element increases from x = 0 to 1. Coercive field ( H C), remanent magnetization ( M r), and saturation magnetization ( M S) respectively display the monotonous variation phenomena with increasing content of Fe. The increasing M r, M S and the decreasing H C can be attributed to the change of magnetic exchange interaction because of the doped Fe. It also proves that the magnetic properties of CuCr2- x Fe x O4 ceramics can be effectively tuned by the doping content of Fe.

  13. Thermal expansion and magnetostriction measurements of the mixed systems Cs{sub 2}CuCl{sub 4-x}Br{sub x} (0 ≤ x ≤ 4)

    Energy Technology Data Exchange (ETDEWEB)

    Thallapaka, Satya Krishna; Tutsch, Ulrich; Postulka, Lars; Wolf, Bernd; Lang, Michael; Well, Natalia van; Ritter, Franz; Krellner, Cornelius [Frankfurt Univ., Frankfurt am Main (Germany). Physics Inst., SFB/TR 49

    2015-07-01

    The mixed systems Cs{sub 2}CuCl{sub 4-x}Br{sub x} (0 ≤ x ≤ 4), including the two well-known end members Cs{sub 2}CuCl{sub 4} and Cs{sub 2}CuBr{sub 4}, are classified as quasi-two-dimensional quantum antiferromagnets with different degrees of magnetic frustration. Due to a site-selective substitution of the halide atoms two distinct critical concentrations (x = 1 and x = 2) had been identified. Especially the Cs{sub 2}CuCl{sub 2}Br{sub 2} compound exhibits the potential to be the system with the highest degree of frustration within this series. We present low-temperature thermal expansion measurements down to 40 mK and magnetostriction experiments up to 14 T on the Cs{sub 2}CuCl{sub 2}Br{sub 2} compound. While specific heat measurements reveal indications for magnetic order around 90 mK, no clear signatures were found in thermal expansion studies along the b axis. Here an in-T linear contribution was observed indicating a 1D character of the magnetic excitations. For fields above 5 T one finds a clear deviation from this linearity. These results are discussed with specific heat data and also compared with the thermodynamic properties of the pure Cs{sub 2}CuCl{sub 4} compound.

  14. Evidence of Charge Transfer and Orbital Magnetic Moment in Multiferroic CuFeO2

    Science.gov (United States)

    Narumi, Yasuo; Nakamura, Tetsuya; Ikeno, Hidekazu; Terada, Noriki; Morioka, Takayuki; Saito, Kota; Kitazawa, Hideaki; Kindo, Koichi; Nojiri, Hiroyuki

    2016-11-01

    Soft X-ray absorption spectra (XAS) and magnetic circular dichroism (XMCD) of Fe and Cu L2,3 edges have been measured on the triangular lattice antiferromagnet CuFeO2. By applying sum rule analysis to the XMCD of Fe, the ratio of the orbital to spin magnetic moments is determined to be -0.071. Because the nominal valence of Fe in CuFeO2 was Fe3+ (3d5), the orbital magnetic moment was considered to be zero in the past. However, the present research demonstrates that the orbital magnetic moment of Fe takes a finite value and it is possibly due to Fe4+ (3d4), which is considered to be responsible for the strong magnetic anisotropy and the ferroelectricity. We compare the experimental results with the results of ab initio multiplet calculations based on the configuration interaction theory and discuss the anomalous electronic structures of Fe and Cu ions in CuFeO2.

  15. Effect of Cu doping on the structure and phase transition of directly synthesized FePt nanoparticles

    Science.gov (United States)

    Wang, Hanbin; Li, Yang; Chen, Xu; Shu, Dan; Liu, Xiang; Wang, Xina; Zhang, Jun; Wang, Hao; Wang, Yi; Ruterana, Pierre

    2017-01-01

    In this work, ternary Cu doped FePt nanoparticles were prepared in hexadecylamine at 320 °C by choosing FeCl2 as the Fe source. The experimental results showed that without Cu doping the as-prepared FePt nanoparticles possessed fcc structure and gradually exhibited typical fct diffraction peaks after increasing the Cu doping concentration. TEM images showed that the FePt nanoparticles had larger size and wider size distribution after introducing Cu additive. Magnetic property measurement showed that a coercivity of 4800 Oe was obtained when the composition of the ternary nanoparticles reached Fe35Pt45Cu20, in which the content of Fe+Cu was higher than Pt. The research indicates that Cu doping promotes the phase transition of FePt nanoparticles at temperature as low as 320 °C.

  16. Synchrotron X—Ray Study on Structures of Ni80Fe20/Cu Superlattices

    Institute of Scientific and Technical Information of China (English)

    杨涛; 麦振洪; 赖武彦; 吴忠华; 王德武; XUMing; 罗光明; 柴春林

    2001-01-01

    We have shown that,in contrast to the results in the literature,the Bragg peak intensity of Ni80Fe20/Cu superlattices is enhanced at the incident x-ray energy slightly higher than the absorption edge of the heavier element(Cu).The atomic density at Ni80Fe20/Cu interface was analysed by the diffraction anomalous fine structure technology with the incident angle of x-ray fixed at the first Bragg peak.Our results demonstrate the epitaxy growth of Ni80Fe20/Cu superlattices.Upon annealing,the epitaxity of Ni80Fe20/Cu multilayers becomes poor but the local crystallinity in each layer is improved.

  17. Direct Measurement of the Metastable Liquid Miscibility Gap in Fe-Co-Cu Ternary Alloy System

    Institute of Scientific and Technical Information of China (English)

    CAO Chong-De; Georg P.G(O)RLER

    2005-01-01

    @@ The metastable liquid-liquid phase separation in undercooled Fe-Co-Cu ternary alloy melts (XCu = 0.10-0.84;XCo:XFe = 1:3,1:1 and 3:1) is investigated by differential thermal analysis in combination with glass fluxing technique. In almost every case, the undercooling of the homogeneous alloy melt was sufficient to reach the boundary line of the submerged miscibility gap. The differential-thermal-analysis signals indicate that this separation into a (Fe, Co)-rich liquid phase L1 and a Cu-rich liquid L2 is exothermic and proceeds until the rapid solidification of the L1 phase occurs. At a given Cu concentration and with the increase of Co content, the phase separation temperatures decrease monotonically between the corresponding values of the boundary systems Fe-Cu and Co-Cu. The boundary lines of the miscibility gap, which are determined for the three quasi-binary cross-sections of the (Fe, Co)-Cu alloy system, show remarkably flat domes. The occurrence of the liquid phase separation shows an evident influence on the subsequent γ-Fe(Co, Cu)→α-Fe(Co, Cu) solid phase transformation.

  18. Enthalpy of mixing of liquid Cu-Fe-Hf alloys at 1873 K

    Energy Technology Data Exchange (ETDEWEB)

    Agraval, Pavel; Turchanin, Mikhail [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Dreval, Liya [Donbass State Engineering Academy, Kramatorsk (Ukraine). Metallurgical Dept.; Materials Science International Services GmbH (MSI), Stuttgart (Germany)

    2016-12-15

    In the ternary Cu-Fe-Hf system, the mixing enthalpies of liquid alloys were investigated at 1873 K using a high-temperature isoperibolic calorimeter. The experiments were performed along the sections x{sub Cu}/x{sub Fe} = 3/1, 1/1 at x{sub Hf} = 0-0.47 and along the section x{sub Cu}/x{sub Fe} = 1/3 at x{sub Hf} = 0-0.13. The limiting partial enthalpies of mixing of undercooled liquid hafnium in liquid Cu-Fe alloys, Δ{sub mix} anti H{sub Hf}{sup ∞}, are (-122 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 3/1), (-106 ± 9) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/1), and (-105 ± 2) kJ mol{sup -1} (section x{sub Cu}/x{sub Fe} = 1/3). In the investigated composition range, the integral mixing enthalpies are sign-changing. For the integral mixing enthalpy, an analytical expression was obtained by the least squares fit of the experimental results using the Redlich-Kister-Muggianu polynomial.

  19. Structural evolutions of the mechanically alloyed Al70Cu20Fe10 powders

    Indian Academy of Sciences (India)

    Musa Göğebakan; Bariş Avar

    2011-10-01

    Elemental mixtures of Al, Cu, Fe powders with the nominal composition of Al70Cu20Fe10 were mechanically alloyed in a planetary ball mill for 80 h. Subsequent annealing of the as-milled powders were performed at 600–800°C temperature range for 4 h. Structural characteristics of the mechanically alloyed Al70Cu20Fe10 powders with the milling time and the heat treatment were investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and differential thermal analysis (DTA). Mechanical alloying of the Al70Cu20Fe10 did not result in the formation of icosahedral quasicrystalline phase (i-phase) and a long time milling resulted in the formation of -Al(Cu,Fe) solid solution phase (-phase). The i-phase was observed only for short-time milled powders after heat treatment above 600°C. The -phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation indicated that a suitable technique to obtain a large amount of quasicrystalline powders is to use a combination of short-time milling and subsequent annealing.

  20. Structure and stress in Cu/Au and Fe/Au systems: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Zientarski, Tomasz, E-mail: martom@dyzio.umcs.lublin.pl [Department for the Modelling of Physico-Chemical Processes, Maria Curie-Skłodowska University, ul. Gliniana 33, 20-614 Lublin (Poland); Chocyk, Dariusz [Department of Applied Physics, Lublin University of Technology, ul. Nadbystrzycka 38, 20-618 Lublin (Poland)

    2014-07-01

    Growth of Fe and Cu thin films on Au substrate and stress evolution were modeled using molecular dynamics simulation. The interactions in the system are described by embedded atom method. The kinematical theory of scattering is performed to identify the structure obtained from simulations. The gold layers undergo reconstruction before deposition. The deposited copper atoms do not disturb the atoms in the reconstructed gold layer, but the deposited iron atoms cause the disappearance of the reconstructed gold surfaces. In both systems Cu/Au and Fe/Au, in the early stage of growth one observes compressive stress. Next, Cu/Au systems have the compressive stress, while in the case of Fe/Au the tensile stress is observed. In the Fe/Au system, the body-centered cubic lattice of Fe changes its orientation relative to the Au layer. In the Fe/Au system we observed a larger diffusion of Au atoms than in Cu/Au systems. - Highlights: • The kinematical theory of scattering is performed to identify the structure. • The correlation between the stress and the deformation is observed. • The relaxation of the stress depends on the orientation of layers. • The lattice of Fe changes its orientation relative to the Au layer in the Fe/Au system. • The Cu layer continues the lattice of Au in the Cu/Au system.

  1. Isolation and characterization of a new Cu-Fe protein from Desulfovibrio aminophilus DSM12254.

    Science.gov (United States)

    Rivas, Maria G; Mota, Cristiano S; Pauleta, Sofia R; Carepo, Marta S P; Folgosa, Filipe; Andrade, Susana L A; Fauque, Guy; Pereira, Alice S; Tavares, Pedro; Calvete, Juan J; Moura, Isabel; Moura, José J G

    2009-10-01

    The isolation and characterization of a new metalloprotein containing Cu and Fe atoms is reported. The as-isolated Cu-Fe protein shows an UV-visible spectrum with absorption bands at 320 nm, 409 nm and 615 nm. Molecular mass of the native protein along with denaturating electrophoresis and mass spectrometry data show that this protein is a multimer consisting of 14+/-1 subunits of 15254.3+/-7.6 Da. Mössbauer spectroscopy data of the as-isolated Cu-Fe protein is consistent with the presence of [2Fe-2S](2+) centers. Data interpretation of the dithionite reduced protein suggest that the metallic cluster could be constituted by two ferromagnetically coupled [2Fe-2S](+) spin delocalized pairs. The biochemical properties of the Cu-Fe protein are similar to the recently reported molybdenum resistance associated protein from Desulfovibrio, D. alaskensis. Furthermore, a BLAST search from the DNA deduced amino acid sequence shows that the Cu-Fe protein has homology with proteins annotated as zinc resistance associated proteins from Desulfovibrio, D. alaskensis, D. vulgaris Hildenborough, D. piger ATCC 29098. These facts suggest a possible role of the Cu-Fe protein in metal tolerance.

  2. Dechlorination of carbon tetrachloride by the catalyzed Fe-Cu process

    Institute of Scientific and Technical Information of China (English)

    XU Wen-ying; GAO Ting-yao

    2007-01-01

    The electrochemical reduction characteristics of carbon tetrachloride (CT) were investigated using cyclic voltammetry in this study. In addition, the difference in reduction mechanisms of CT between Master Builders' iron and the catalyzed Fe-Cu process was discussed. The results showed that CT was reduced directly on the surface of copper rather than by atomic hydrogen produced at the cathode in the catalyzed Fe-Cu process. The reduction was realized largely by atomic hydrogen in Master Builders' iron. The entire CT in 350 ml aqueous solution with 320 mg/L was reduced to trichloromethane and dichloromethane in 2.25 h when 100 g of scrap iron with Fe/Cu ratio of 10:1 (w/w) were used. Moreover, the reduction rate slowed with time. CT could be reduced at acidic, neutral and alkaline pH from solution by Fe-Cu bimetallic media, but the mechanisms were different. The degradation rate was not significantly influenced by pH in the catalyzed Fe-Cu process; in Master Builders' iron it clearly increased with decreasing pH. The kinetics of the reductions followed pseudo-first order in both cases. Furthermore, the reductions under acidic conditions proceeded faster than that under the neutral and alkaline conditions. The catalyzed Fe-Cu process was superior to Master Builders' iron in treating CT-containing water and this advantage was particularly noticeable under alkaline conditions. The reduction was investigated in the cathode (Cu) and anode (Fe) compartments respectively, the results showed that the direct reduction pathway played an important role in the reduction by the catalyzed Fe-Cu process. The catalyzed Fe-Cu process is of practical value.

  3. Nitrate removal by Fe0/Pd/Cu nano-composite in groundwater.

    Science.gov (United States)

    Liu, Hongyuan; Guo, Min; Zhang, Yan

    2014-01-01

    Nitrate pollution in groundwater shows a great threat to the safety of drinking water. Chemical reduction by zero-valent iron is being considered as a promising technique for nitrate removal from contaminated groundwater. In this paper, Fe0/Pd/Cu nano-composites were prepared by the liquid-phase reduction method, and batch experiments of nitrate reduction by the prepared Fe0/Pd/Cu nano-composites under various operating conditions were carried out. It has been found that nano-Fe0/Pd/Cu composites processed dual functions: catalytic reduction and chemical reduction. The introduction of Pd and Cu not only improved nitrate removal rate, but also reduced the generation of ammonia. Nitrate removal rate was affected by the amount of Fe0/Pd/Cu, initial nitrate concentration, solution pH, dissolved oxygen (DO), reaction temperature, the presence of anions, and organic pollutant. Moreover, nitrate reduction by Fe0/Pd/Cu composites followed the pseudo-first-order reaction kinetics. The removal rate of nitrate and total nitrogen were about 85% and 40.8%, respectively, under the reaction condition of Fe-6.0%Pd-3.0%Cu amount of 0.25 g/L, pH value of 7.1, DO of 0.42 mg/L, and initial nitrate concentration of 100 mg/L. Compared with the previous studies with Fe0 alone or Fe-Cu, nano-Fe-6%Pd-3%Cu composites showed a better selectivity to N2.

  4. Novel Fluorescent Chemosensors Based on Tryptophan Unit for Cu2+ and Fe3+ in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    CHENG Peng-fei; XU Kuo-xi; YAO Wen-yong; KONG Hua-jie; KOU Li; MA Xiao-dan; WANG Chao-jie

    2013-01-01

    We reported four fluorescent chemosensors containing tryptophan units.The fluorescence spectrum titration experiments suggest that chemosensors 1,2,3 and 4 are highly selective for Cu2+ and Fe3+ over Li+,Na+,K+,Co2+,Zn2+,Ni2+,Hg2+ and Cr3+ via forming complexes with Cu2+ or Fe3+,which is confirmed by dramatical quench of fluoreseence in aqueous solution at pH 7.4,thus making all the chemosensors suitable for Cu2+ and Fe3+ fluorescent sensors.

  5. A General and Efficient CuBr2-Catalyzed N-Arylation of Secondary Acyclic Amides

    Institute of Scientific and Technical Information of China (English)

    王满刚; 于华; 尤心稳; 吴军; 商志才

    2012-01-01

    A general and efficient Cu(II)-catalyzed cross-coupling method is reported for the preparation of acyclic tertiary amides. Generally moderate to excellent yields and functional group tolerance were obtained with secondary acyclic amides and aryl halides as substrates in toluene.

  6. Conversion of syngas to higher alcohols over Cu-Fe-Zr catalysts induced by ethanol

    Institute of Scientific and Technical Information of China (English)

    Hongtao Zhang; Xiaomei Yang; Lipeng Zhou; Yunlai Su; Zhongmin Liu

    2009-01-01

    Ethanol induced method was applied to prepare Cu-Fe-Zr catalysts for conversion of syngas to higher alcohols. The catalytic performance of the catalysts induced by ethanol was superior to that of the catalyst prepared by the conventional precipitation method. Among various procedures for ethanol induced method,it was found that incorporation of ethanol in the precipitation process was the better. After incorporation of ethanol,the crystal size of CuO decreased and the reduction of copper species became easier. The better activity of Cu-Fe-Zr catalysts prepared by ethanol induced procedures was probably caused by the higher dispersion of Cu species.

  7. Kinetic analysis of the factors limiting the output power of the Ne-CuBr UV laser

    Institute of Scientific and Technical Information of China (English)

    Mao Bang-Ning; Pan Bai-Liang; Chen Li; Wang Ya-Juan; Yao Zhi-Xin

    2009-01-01

    The parametric optimization of the Ne-CuBr UV laser excited by longitudinal pulsed discharge is analysed by using a self-consistent kinetic model.Consistent characteristics of the optimization process are obtained by comparing with the experimental results.Simulation results show that neon ions come into being along with considerable depletion of the ground-state copper atoms.And the optimization of the discharge tube diameter is the tradeoff between the specific output photon density and the total active volume.Both the optimal neon gas pressure and the optimal reservoir temperature result from the balance between the neon ion density and the ground-state copper atom density to arrive at a maximum of their product.

  8. EXAFS STUDY OF THE SHORT RANGE STRUCTURE OF NANOCRYSTALLINE BCC-Fe80Cu20 SOLID SOLUTION

    Institute of Scientific and Technical Information of China (English)

    Y.Z. Yang; X.J. Bai; T.C. Kuang; G.M. Wang; S. Q. Wei

    2002-01-01

    The structure of bcc-Fe80 Cu2o solid solution produced by mechanical alloying of theelemental bcc-Fe and fcc-Cu powders has been studied using X-ray diffraction and theextended X-ray absorption fine structure (EXAFS) techniques. The disappearance ofelemental Fe and Cu X-ray diffraction (XRD) peaks and the presence of bcc structuralXRD peaks illustrate the formation of a nanocrystalline single-phase bcc-Fe80 Gu20solid solution. From the EXAFS results, the clear observation of Cu atoms taking onbcc coordination in the solid solution and Fe atoms remaining bcc structure furtherverifies the reality of atomic alloying between Fe and Cu atoms and the lattice changeof Cu from fcc to bcc. However, the supersaturated bcc solid solution is not chemicallyuniform, i.e., some regions are rich in Fe atoms and other regions rich in Cu atoms.

  9. Effect of Applied Current Density on Morphological and Structural Properties of Electrodeposited Fe-Cu Films

    Institute of Scientific and Technical Information of China (English)

    Umut Sarac; M. Celalettin Baykul

    2012-01-01

    A detailed study has been carried out to investigate the effect of applied current density on the composition, crystallographic structure, grain size, and surface morphology of Fe-Cu films. X-ray diffraction (XRD) results show that the films consist of a mixture of face-centered cubic (fcc) Cu and body centered cubic (bcc) ~-Fe phases. The average crystalline size of both Fe and Cu particles decreases as the applied current density becomes more negative. Compositional analysis of Fe-Cu films indicates that the Fe content within the films increases with decreasing current density towards more negative values. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to investigate the surface morphology of Fe-Cu films. It is observed that the surface morphology of the films changes from dendritic structure to a cauliflower structure as the applied current density becomes more negative. The surface roughness and grain size of the Fe-Cu films decrease with decreasing applied current density towards more negative values.

  10. Solute redistribution during phase separation of ternary Fe-Cu-Si alloy

    Science.gov (United States)

    Luo, S. B.; Wang, W. L.; Xia, Z. C.; Wu, Y. H.; Wei, B.

    2015-06-01

    Ternary Fe48Cu48Si4 immiscible alloy was rapidly solidified under the containerless microgravity condition inside a drop tube. Liquid phase separation took place in the alloy melt and led to the formation of various segregated structures. The core-shell structure consisting of Fe-rich and Cu-rich zones and the homogenously dispersed structure were the major structural morphologies. Phase field simulation results revealed that the two-layer core-shell was the final structure of liquid phase separation. The solute redistribution of liquid Fe48Cu48Si4 alloy experienced the macroscopic solute distribution induced by liquid phase separation, the secondary phase separation within the separated liquid phases and the solute trapping during rapid solidification. Energy dispersive spectroscopy analysis showed that the solute Si was enriched in the Fe-rich zone whereas depleted in the Cu-rich zone. In addition, both αFe and (Cu) phases in the Fe-rich zone exhibited a conspicuous solute trapping effect. As compared with (Cu) phase, αFe phase had a stronger affinity with solute Si.

  11. The electrical conductivity characteristics of Fe/Cu nano-scale multilayer materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mathematical model for describing the relationship betweenelectrical conductivity and the thickness of bilayer, ratio of sublayer thickness of a nano-scale multilayer material (MLM) is presented. Fe/Cu MLM was synthesized by electron beam physical vapor deposition (EB-PVD) technique, and the dependence of electrical conductivity of Fe/Cu MLM on the bilayer thickness and ratio of sublayer thickness were investigated. It is shown that the electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness decreases sharply when the thickness of bilayer becomes thinner than 30 nm. When the bilayer thickness is kept constant, the electrical conductivity linearly decreases with the increasing ratio of sublayer thickness. The values of parameters in the model were obtained by fitting the measured results of electrical conductivity of Fe/Cu MLM with fixed ratio of sublayer thickness. It is found that the calculated values agree well with measured ones.

  12. Photocatalytic Characterization of Fe- and Cu-Doped ZnO Nanorods Synthesized by Cohydrolysis

    Directory of Open Access Journals (Sweden)

    Young Rang Uhm

    2013-01-01

    Full Text Available Fe- and Cu-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn, Fe, and Cu nanopowders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60°C for 24 h to obtain the precipitates from the hydrolysis of Zn and dopants (Cu and Fe. The TEM results for ZnO with and without metal doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing doping content, the UV-vis spectra were shifted to a long wavelength and this result indicates that the band gap was changed by the metal doping. The values of phenol degrading Fe- and Cu-doped ZnO by a solar simulator were measured to be 60 and 75%, respectively.

  13. ELECTROMAGNETIC MICROWAVE PROPERTIES OF Fe82B17Cu1 BALL MILLED ALLOY

    Science.gov (United States)

    Tian, N.; Fan, X. D.; Wang, J. W.; You, C. Y.; Lu, Z. X.; Ge, L. L.

    2013-07-01

    High saturation magnetization and magnetic anisotropy are helpful for getting a high frequency electromagnetic microwave absorption performance. The α-Fe possesses a high saturation magnetization. Fe-B phases exhibit a relatively higher magnetic anisotropy and higher resistivity than α-Fe simultaneously. In this work, we made nanocrystalline powders of Fe82B17Cu1, mainly consisting of α-Fe and Fe2B phases, by ball milling and post-annealing. Electromagnetic microwave characterization shows that Fe82B17Cu1 powders possess a relative high permeability and considerable permittivity. Due to a good electromagnetic impedance matching, a good electromagnetic microwave absorption property (RL < -35 dB) has been achieved at 3.6 GHz. The experimental frequency and the matching thickness are coincident with the quarter wavelength matching condition.

  14. Evaporation Mechanism of Cu from Liquid Fe Containing C and S

    Science.gov (United States)

    Jung, Sung-Hoon; Kang, Youn-Bae

    2016-08-01

    A number of liquid-gas experiments were carried out in order to elucidate evaporation mechanism of Cu from liquid Fe containing C and S. Rate of Cu evaporation in liquid Fe droplets at 1873 K (1600 °C) was determined using electromagnetic levitation equipment. Evaporation rate of the Cu under various conditions (flow rate of gas mixtures, initial C, and S concentrations) was examined. It was found from a series of kinetic analyses of the experimental data that Cu evaporates in forms of Cu(g) and CuS(g). As was reported for the Sn evaporation from liquid iron (Jung et al. Met. Mater. Trans. 46B, 250-258, 2014), S plays two roles for the evaporation of Cu: accelerating the rate by forming CuS(g) and decelerating the rate by blocking evaporation sites. As a result of these combinatorial effects, the evaporation of Cu is decelerated at low S content, but is accelerated at high S content. Based on the elucidated mechanism, an evaporation model equation for Cu was developed in the present study, which takes into account (1) evaporation of Cu in the two forms (Cu(g) and CuS(g)), (2) surface blocking by S using ideal Langmuir adsorption, and (3) effect of C. The obtained rate constant of a reaction Cu i + S i = CuS i (g), k CuS R , is 1.37 × 10-9 m4 mol-1 s-1, and the residual rate constant, k CuS r , is 4.11 × 10-10 m4 mol-1 s-1 at 1873 K (1600 °C). Both of them were found to be one order lower than those for Sn evaporation.

  15. Effects of interfacial transition layers on the electrical properties of individual Fe 30 Co 61 Cu 9 /Cu multilayer nanowires

    KAUST Repository

    Ma, Hongbin

    2016-01-01

    In this work, we accurately measure the electrical properties of individual Fe30Co61Cu9/Cu multilayered nanowires using nanomanipulators in in situ scanning electron microscopy to reveal that interfacial transition layers are influential in determining their transport behaviors. We investigate the morphology, crystal structure and chemistry of the Fe30Co61Cu9/Cu multilayered nanowires to characterize them at the nanoscale. We also compare the transport properties of these multilayered nanowires to those of individual pure Cu nanowires and to those of alloy Fe30Co61Cu9 nanowires. The multilayered nanowires with a 50 nm diameter had a remarkable resistivity of approximately 5.41 × 10-7 Ω m and a failure current density of 1.54 × 1011 A m-2. Detailed analysis of the electrical data reveals that interfacial transition layers influence the electrical properties of multilayered nanowires and are likely to have a strong impact on the life of nanodevices. This work contributes to a basic understanding of the electrical parameters of individual magnetic multilayered nanowires for their application as functional building blocks and interconnecting leads in nanodevices and nanoelectronics, and also provides a clear physical picture of a single multilayered nanowire which explains its electrical resistance and its source of giant magnetoresistance. © The Royal Society of Chemistry 2016.

  16. Structural and magnetic properties of Cu-alloyed FePd films

    Energy Technology Data Exchange (ETDEWEB)

    Polit, A., E-mail: aleksander.polit@gmail.com [The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-348 Krakow (Poland); Makarov, D., E-mail: d.makarov@ifw-dresden.de [Chemnitz University of Technology, Institute of Physics, D-09107 Chemnitz (Germany); Brombacher, C., E-mail: Christoph.Brombacher@vacuumschmelze.com [Chemnitz University of Technology, Institute of Physics, D-09107 Chemnitz (Germany); Krupinski, M., E-mail: michal.krupinski@ifj.edu.pl [The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-348 Krakow (Poland); Perzanowski, M., E-mail: marcin.perzanowski@ifj.edu.pl [The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-348 Krakow (Poland); Zabila, Y., E-mail: yevhen.zabila@ifj.edu.pl [The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-348 Krakow (Poland); Albrecht, M., E-mail: manfred.albrecht@physik.uni-augsburg.de [Chemnitz University of Technology, Institute of Physics, D-09107 Chemnitz (Germany); Marszałek, M., E-mail: marta.marszalek@ifj.edu.pl [The H. Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, 31-348 Krakow (Poland)

    2015-05-01

    Multilayer films [Cu(d Å)/Fe(9 Å)/Pd(11 Å)]{sub 5} were deposited at room temperature on Si(001)/SiO{sub 2}(400 nm) substrates. In order to induce chemical L1{sub 0} ordering, the as-deposited samples were post-annealed by rapid thermal annealing (RTA) at 600 °C for 90 s followed additionally by heating in ultra-high vacuum (UHV) at 700 °C up to several hours. In this study the impact of post-annealing on the structural and magnetic properties of FePdCu alloy films in dependence on the Cu content was investigated. It was found that the addition of Cu to the FePd alloy has a strong influence on the chemical ordering process and the (001) texture formation. After the RTA treatment only an isotropic distribution of the easy axis of magnetization with coercive fields in the range of a few hundred mT was observed. In contrast, samples which were additionally heated for 1 h at 700 °C revealed an out-of-plane easy axis of magnetization with an effective magnetic anisotropy of about 2×10{sup 5} J/m{sup 3} for the sample containing 10 at% of Cu. - Highlights: • Fabrication by two-step annealing of FePdCu thin alloy films. • The impact of post-annealing on the structural and magnetic properties of FePdCu alloy films. • The addition of Cu to the FePd alloy has a strong influence on the chemical ordering process and the (001) texture formation. • Importance of texture in polycrystalline L1{sub 0} FePdCu alloy for perpendicular magnetic anisotropy.

  17. Microstructural and magnetic characterizations of CoFeCu electrodeposited in self-assembled mesoporous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Fortas, G., E-mail: g.fortas@gmail.com [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Haine, N. [Université des Sciences et de la Technologie Houari Boumediene, Faculté des Physique, BP 32 El Alia 16111 Bab Ezzouar, Alger (Algeria); Sam, S.; Gabouze, N. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria); Saifi, A. [Université Mouloud Mammeri, laboratoire de physique et de chimie quantique, BP No. 17 RP Hasnaoua Tizi-Ouzou 15000 (Algeria); Ouir, S. [Université Said SDB, Route De Soumaa BP 270, Blida (Algeria); Menari, H. [Centre de Recherche en Technologie des Semi-conducteur pour l’Energétique, Bd. 2 Frantz Fanon, les sept merveilles B.P.140, Alger (Algeria)

    2015-03-15

    Self-assembled mesoporous silicon with quasi-regular pore arrangements has been fabricated by the electrochemical anodization process in hydrofluoric acid solution. CoFeCu was electrodeposited in this structure from a bath containing sodium acetate as a complexing agent with a pH value of 5. The effect of current density on the morphology, the structure and the magnetic properties of CoFeCu deposit was studied by SEM, EDS, DRX and VSM. It has been shown that the morphology and structure of samples were strongly influenced by the current density and etching duration. The micrographs show the vertical and branched nanowires and also a discontinuous growth of wires. Further, the growth of a thick layer from the grain boundaries of released CoFeCu wires is produced. The magnetic hysteresis loops demonstrate that the CoFeCu nanowires exhibit easy magnetic axis perpendicular to the PS channels axis when the current density varied from 3 to 10 mA/cm{sup 2}. Nevertheless, they reveal a no magnetic anisotropy of CoFeCu nanostructures deposited only in the outside of porous silicon, probably due to the vanishing the shape anisotropy. - Highlights: • CoFeCu deposit has been electrodeposited on self assembled mesoporous silicon. • SEM observation shows that CoFeCu embedded in Porous silicon channels. • Magnetic measurements show the anisotropy magnetic behavior of CoFeCu nanostructures. • The growth rate of nanowires is enhanced with an increase of current density.

  18. Metastable fcc-Fe film epitaxially grown on Cu(100) single-crystal underlayer

    Science.gov (United States)

    Ohtake, Mitsuru; Shimamoto, Kohei; Futamoto, Masaaki

    2013-05-01

    Fe film of 40 nm thickness is prepared on fcc-Cu(100) single-crystal underlayer at room temperature by ultra-high vacuum molecular beam epitaxy. The film growth and the detailed structure are investigated by reflection high-energy electron diffraction, cross-sectional high-resolution transmission electron microscopy (HR-TEM), and x-ray diffraction (XRD). An Fe single-crystal with metastable fcc structure nucleates on the underlayer. The HR-TEM shows that fcc lattice is formed from the Fe/Cu interface up to the film surface. A large number of misfit dislocations are introduced around the Fe/Cu interface due to an accommodation of lattice mismatch. Dislocations exist up to the film near surface. The lattice constant is estimated by XRD to be a = 0.3607 nm. The film shows a ferromagnetic property, which reflects the property of fcc-Fe crystal with high-spin ferromagnetic state.

  19. Structural, electronic, and elastic properties of CuFeS2: first-principles study

    Science.gov (United States)

    Zhou, Meng; Gao, Xiang; Cheng, Yan; Chen, Xiangrong; Cai, Lingcang

    2015-03-01

    The structural, electronic, and elastic properties of CuFeS2 have been investigated by using the generalized gradient approximation (GGA), GGA + U (on-site Coulomb repulsion energy), the local density approximation (LDA), and the LDA + U approach in the frame of density functional theory. It is shown that when the GGA + U formalism is selected with a U value of 3 eV for the 3d state of Fe, the calculated lattice constants agree well with the available experimental and other theoretical data. Our GGA + U calculations indicate that CuFeS2 is a semiconductor with a band gap of 0.552 eV and with a magnetic moment of 3.64 µB per Fe atom, which are well consistent with the experimental results. Combined with the density of states, the band structure characteristics of CuFeS2 have been analyzed and their origins have been specified, which reveals a hybridization existing between Fe-3d, Cu-3s, and S-3p, respectively. The charge and Mulliken population analyses indicate that CuFeS2 is a covalent crystal. Moreover, the calculated elastic constants prove that CuFeS2 is mechanically stable but anisotropic. The bulk modulus obtained from elastic constants is 87.1 GPa, which agrees well with the experimental value of 91 ± 15 GPa and better than the theoretical bulk modulus 74 GPa obtained from GGA method by Lazewski et al. The obtained shear modulus and Debye temperature are 21.0 GPa and 287 K, respectively, and the latter accords well with the available experimental value. It is expected that our work can provide useful information to further investigate CuFeS2 from both the experimental and theoretical sides.

  20. Persistence of singlet fluctuations in the coupled spin tetrahedra system Cu2Te2O5Br2 revealed by high-field magnetization, 79Br NQR, and 125Te NMR

    Science.gov (United States)

    Baek, S.-H.; Choi, K.-Y.; Berger, H.; Büchner, B.; Grafe, H.-J.

    2012-11-01

    We present high-field magnetization and 79Br nuclear quadrupole resonance (NQR) and 125Te nuclear magnetic resonance (NMR) studies in the weakly coupled Cu2+ (S=1/2) tetrahedral system Cu2Te2O5Br2. The field-induced level crossing effects were observed by the magnetization measurements in a long-ranged magnetically ordered state which was confirmed by a strong divergence of the spin-lattice relaxation rate T1-1 at T0=13.5 K. In the paramagnetic state, T1-1 reveals an effective singlet-triplet spin gap much larger than that observed by static bulk measurements. Our results imply that the inter- and the intratetrahedral interactions compete, but at the same time they cooperate strengthening effectively the local intratetrahedral exchange couplings. We discuss that the unusual feature originates from the frustrated intertetrahedral interactions.

  1. Antiferroelectric instability in the kagome francisites Cu3Bi (SeO3)2O2X (X =Cl ,Br )

    Science.gov (United States)

    Prishchenko, Danil A.; Tsirlin, Alexander A.; Tsurkan, Vladimir; Loidl, Alois; Jesche, Anton; Mazurenko, Vladimir G.

    2017-02-01

    Density-functional calculations of lattice dynamics and high-resolution synchrotron powder diffraction uncover antiferroelectric distortion in the kagome francisite Cu3Bi (SeO3)2O2Cl below 115 K. Its Br-containing analog is stable in the room-temperature crystal structure down to at least 10 K, although the Br compound is on the verge of a similar antiferroelectric instability and reveals local displacements of Cu and Br atoms. The I-containing compound is stable in its room-temperature structure according to density-functional calculations. We show that the distortion involves cooperative displacements of Cu and Cl atoms, and originates from the optimization of interatomic distances for weakly bonded halogen atoms. The distortion introduces a tangible deformation of the kagome spin lattice and may be responsible for the reduced net magnetization of the Cl compound compared to the Br one. The polar structure of Cu3Bi (SeO3)2O2Cl is only slightly higher in energy than the nonpolar antiferroelectric structure, but no convincing evidence of its formation could be obtained.

  2. Spontaneous piezoelectric effect as order parameter in (NH4)2CuBr4·2H2O crystal

    Science.gov (United States)

    Tylczyński, Z.; Wiesner, M.; Trzaskowska, A.

    2016-11-01

    Temperature change of piezoelectric properties of (NH4)2CuBr4·2H2O crystal in the low-temperature ferroelastoelectric phase is studied. The macroscopic order parameter is proved to be the h36 component of the spontaneous piezoelectric tensor. The critical exponent related with the phase transition is α=0.60±0.05.

  3. Vortex dynamics in organic superconductor {kappa}-(ET){sub 2}X(X=Cu(NCS){sub 2}, Cu[N(CN){sub 2}]Br)

    Energy Technology Data Exchange (ETDEWEB)

    Simizu, T. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Yoshimoto, N. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Nakanishi, Y. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, Morioka 020-8551 (Japan)]. E-mail: yoshizawa@iwate-u.ac.jp

    2006-05-01

    Organic superconductors {kappa}-(ET){sub 2}X (X=Cu(NCS){sub 2}, Cu[N(CN){sub 2}]Br) show anomalous elastic properties in both normal and superconducting states. We have measured the sound velocity of these salts near the superconducting transition temperature T{sub c} in the selected magnetic fields with different directions. Under the magnetic field, the sound velocity as a function of temperature shows remarkable elastic anomalies. It was mainly caused by interplay between the vortices and the elastic strain. The {delta}C{sub S-N}, which is the difference of elastic constant C(T) in the superconducting state from the normal state, shows the softening toward lower temperature after following the jump at T{sub c}. This discontinuous jump at T{sub c} has been found on the longitudinal mode and on the transverse mode. It suggests that two-dimensional order parameter plays an important role in the superconductivity of {kappa}-(ET){sub 2}X system.

  4. Geochemistry of magnetite from Proterozoic Fe-Cu deposits in the Kangdian metallogenic province, SW China

    Science.gov (United States)

    Chen, Wei Terry; Zhou, Mei-Fu; Gao, Jian-Feng; Hu, Ruizhong

    2015-10-01

    Fe-Cu deposits in the Kangdian Fe-Cu metallogenic province, SW China, are hosted in Paleoproterozoic meta-volcanic-sedimentary sequences and are spatially associated with coeval mafic intrusions. Several well-known examples are the giant Lala, Dahongshan, and Yinachang deposits. They have a common paragenetic sequence of an early Fe-oxide stage associated with sodic alteration and a late Cu-sulfide stage associated with potassic-carbonate alteration. Magnetite dominates the Fe-oxide stage of these deposits but is also present in the Cu-sulfide stage of the Lala deposit. This study uses trace element compositions of magnetite to examine the nature and origin of the ore-forming fluids. The magnetite has variable concentrations of Ti, Al, Mg, Mn, Si, V, Cr, Ca, Co, Ni, Sc, Zn, Cu, Mo, Sn, and Ga, which are thought to have been controlled mainly by fluid compositions and/or intensive parameters (e.g., temperature and oxygen fugacity ( fO2)). Fluid-rock interaction and coprecipitating mineral phases appear to be less important in controlling the magnetite compositions. Magnetite grains in the Fe-oxide stage of the Lala and Dahongshan deposits have comparable trace element compositions and were likely precipitated from chemically similar fluids. High Ni contents of magnetite in both deposits, coupled with previous isotopic data and the fact that the two deposits are spatially associated with coeval mafic intrusions, strongly suggest that the ore-forming fluids were genetically related to the mafic magmas that formed the intrusions. Magnetite grains in the Fe-oxide stage of the Yinachang deposit have much lower V and Ni but higher Sn and Mo contents than those of the Lala and Dahongshan deposits and are thus thought to have precipitated from more oxidized and Mo-Sn-rich fluids that may have evolved from relatively felsic magmas. Magnetite grains from the Cu-sulfide and Fe-oxide stages of the Lala deposit are broadly similar in composition, but those in the Cu

  5. Geomaterials related to photovoltaics: a nanostructured Fe-bearing kuramite, Cu3SnS4

    Science.gov (United States)

    Di Benedetto, Francesco; Bencistà, Ilaria; D'Acapito, Francesco; Frizzera, Silvia; Caneschi, Andrea; Innocenti, Massimo; Lavacchi, Alessandro; Montegrossi, Giordano; Oberhauser, Werner; Romanelli, Maurizio; Dittrich, Herbert; Pardi, Luca A.; Tippelt, Gerold; Amthauer, Georg

    2016-09-01

    The successful synthesis of nanoparticles of Fe-bearing kuramite, (Cu,Fe)3SnS4, is reported in this study. Nanocrystalline powders were obtained through a mild, environmentally friendly and scalable solvothermal approach, in a single run. The sample was the object of a multidisciplinary investigation, including X-ray diffraction and absorption, scanning electron microscopy and microanalysis, electron paramagnetic resonance, diffuse reflectance and Mössbauer spectroscopy as well as SQUID magnetometry. The nanoparticles consist of pure Fe-bearing kuramite, exhibiting tetragonal structure. The valence state of the metal cations was assessed to be Cu+, Sn4+ and Fe3+. The material presents a band gap value of 1.6 eV, which is fully compatible with solar cell applications. The uptake of Fe by nanokuramite opens a compositional field where the physical properties can be tuned. We thus foster the application of Fe-bearing nanokuramite for photovoltaics and energy storage purposes.

  6. Spin-Polarized Electron Injection in Co/Cu/Fe Sandwich Structure

    Institute of Scientific and Technical Information of China (English)

    WANG Shou-Guo; CHEN Yan-Xue; WANG Zhi-He; CHEN Qiang; XIE Shi-Jie; MEI Liang-Mo

    2000-01-01

    A material asymmetry Co/Cu/Fe junction structure has been prepared for studying the spin-polarized electron injection at 77K. The sample performance was demonstrated to be analogous to that of a bipolar transistor. The maximal value of the output pulse voltage between Cu and Fe layers could reach the order of severalμV when the bias current between Co and Cu layers was 10μA. The interface roughness, photograph of material, magnetic loop and injection characteristic curves have been measured. Some important points on this topic have been discussed.

  7. Fe+与CH3X(X=Cl,Br,I)反应的理论研究%A Theoretical Study of the Reaction of Fe+ with CH3X (X=Cl, Br,I)

    Institute of Scientific and Technical Information of China (English)

    孙小丽; 李吉来; 黄旭日; 孙家锺

    2013-01-01

    铁及其复合物催化的C—X键功能化日益引起人们的重视.采用密度泛函理论(DFT),在B3LYP/def2-SVP水平下详细研究了Fe+与CH3X (X=Cl,Br,I)的反应活性和机理.计算结果表明标题反应存在两种反应机制,即插入机制和SN2机制.从机理上来看,在插入机理中,反应都始于Fe+离子从侧面进攻CH3X,生成产物FeX+和CH3*;而在SN2机制中,反应则始于Fe+离子从背后进攻CH3X,生成产物FeCH+和X*.从我们的计算可以看出,四重态或六重态下的Fe+离子在C—X键活化中展现了截然不同的催化活性;在所有通道中,都以四重态为主导;SN2机制中相对较高的决速能垒使其丧失了竞争性.再者,计算表明在所有的插入机制中,所有通道都是放热的,而在SN2机制中,仅有X=I时,反应是放热的.此外,计算表明这些反应属于两态反应活性,两种机制中,在反应的入口和出口存在最小能量交叉点.此外,反应途径电子结构追踪分析表明自旋极化对能量影响较大,调控着反应采取的反应通道和主副产物比例.通过本文的理论研究,尤其是详细的电子结构分析,为铁催化剂活化C—X键和C—C耦联反应提供了线索和以铁为基的催化剂设计提供理论依据.

  8. Preparation and oxygen permeation properties of SrFe(Cu)O3-δ dense ceramic membranes

    Institute of Scientific and Technical Information of China (English)

    Heng Zhang; Tingting Wang; Xinfa Dong; Weiming Lin

    2009-01-01

    Mixed oxygen-ionic and electronic conducting membranes of SrFe(Cu)O3-δ were prepared by solid-state reaction method.The crystal structure,oxygen nonstoichiometry,and phase stability of the materials were studied by TGA and XRD.Oxygen permeation fluxes through these membranes were studied at operating temperature ranging from 750 to 950 ℃.Results showed that doping Cu in SrFeO3-δ compound had a significant effect on the formation of single-phased perovskite structure.For SrFe1-xCuxO3-δ series materials,the oxygen nonstoichiometry and the oxygen permeation flux increased considerably with the increase of Cu-doping content (x = 0.1-0.3).The sintering property of the membrane decreased significantly when the Cu substitution amount reached 40%.SrFe0.7CU0.3O3-δ showed high oxygen permeation flux,but SrCuO2 and Sr2Fe2O5 phases formed in the compound after oxygen permeation test induced cracks in the membrane.

  9. PREPARATION OF NANO-CRYSTALLINE Fe-Cu THIN FILMS AND THEIR MAGNETIC PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    X.F.Bi; S.K.Gong; H.B.Xu; K.I.Arai

    2002-01-01

    Fe-Cu thin films of 0.2μm in thickness with different Cu contents were prepared byusing r.f. magnetron sputtering onto glass substrate. The effect of sputtering param-eters, including Ar gas pressure and input rf power, on the structure and magneticproperties was investigated. It was found that when the power is lower than 70W,the structure of the films remained single bcc-Fe phase with Cu solubility of up to50at.%. TEM observations for the bcc-Fe phase showed that the grain size was inthe nanometer range of less than 20nm. The coercivity of Fe-Cu films was largelyaffected by not only Ar gas pressure but also rf power, and reached about 2.5Oe in thepressure of 0.67-6.67Pa and in the power of less than 100W. In addition, saturationmagnetization, with Cu content less than 60at.%, was about proportional to the con-tent of bcc-Fe. When Cu content was at 60at.%, however, saturation magnetizationwas much smaller than its calculation value.

  10. Structural, optical and room-temperature ferromagnetic properties of Fe-doped CuO nanostructures

    Science.gov (United States)

    Mohamed Basith, N.; Judith Vijaya, J.; John Kennedy, L.; Bououdina, M.

    2013-09-01

    Pure CuO and Fe-doped CuO nanostructures with different weight ratios (0.5, 1.0, 1.5, and 2.0 at wt% of Fe) were synthesized via the microwave combustion method. The synthesized samples were characterized by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometry (VSM). XRD patterns refined by the Rietveld method indicated the formation of single-phase monoclinic structure and also confirmed that Fe ions successfully incorporated into CuO crystal lattice by occupying Cu ionic sites. Interestingly, the morphology was found to change considerably from nanoflowers to nano-rod and disk-shaped then to nanoparticles with the variation of Fe content. The optical band gap calculated using DRS was found to be 2.8 eV for pure CuO and increases up to 3.4 eV with increasing ‘Fe’ content. Photoluminescence measurements also confirm these results. The magnetic measurements indicated that the obtained nanostructures are found to be room temperature ferromagnetism (RTF) with an optimum value of saturation magnetization at 2.0 wt% of Fe-doped CuO, i.e. 1.2960×10-3 emu/g.

  11. Preparation of nanometer FeCuP alloy and its application in decomposition of PH3

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A new ternary Fe-based alloy catalyst FeCuP applied to decompose PH3 was prepared with low-cost material by chemical reduction deposition method. The properties of it were characterized by XRD, ICP and SEM. Its catalytic activity on the decomposition of PH3 and the decomposition conditions were studied. FeCuP alloy exhibits high thermal stabilities and high catalytic activity. Using it as catalyst, the decomposition temperature of phosphine decreases from over 800 ℃ to 400-500 ℃. The decomposition rate of phosphine achieved 100%.

  12. Atomic-partial vibrational density of states of i-AlCuFe quasicrystals

    CERN Document Server

    Parshin, P P; Brand, R A; Dianoux, A J; Calvayrac, Y

    2002-01-01

    We present new results on the separation of the atomic-partial vibrational density of states for the ternary quasicrystal i-Al sub 6 sub 2 Cu sub 2 sub 5 sub . sub 5 Fe sub 1 sub 2 sub . sub 5. The decomposition into three atomic-partial functions, Al-, Cu- and Fe-g(E), has been performed self-consistently with the calculation of the multi-phonon contributions. The results show the surprising result that both Cu- and Fe-g(E) are strongly peaked. The low-energy regions of Al- and Cu-g(E) show strong deviations from Debye behaviour due to the presence of non-propagating low-energy vibrational states. (orig.)

  13. Carbon dioxide and water adsorption on highly epitaxial Delafossite CuFeO2 thin film

    Science.gov (United States)

    Rojas, S.; Joshi, T.; Borisov, P.; Sarabia, M.; Lederman, D.; Cabrera, A. L.

    2015-03-01

    Thermal programmed desorption (TPD) of CO2 and H2O from a 200 nm thick CuFeO2 Delafossite surface was performed in a standard UHV chamber, The CuFeO2 thin film grown using Pulsed Laser Deposition (PLD) over an Al2O3 (0001) substrate with controlled O2 atmosphere resulted with highly epitaxial crystal structure. The adsorption/desorption of CO2 and H2O process was also monitored with X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Our results revealed that carbon dioxide interacts with CuFeO2 forming Fe carbonates compounds on its surface. Hydroxides were also formed on the surface due to water presence. Using TPD data, Arrhenius plots for CO2 and water desorption were done and activation energy for desorption was obtained. Funds FONDECyT 1130372; Thanks to P. Ferrari.

  14. Thermodynamic investigations of the quasi-2d triangular Heisenberg antiferromagnet Cs{sub 2}CuCl{sub 2}Br{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tutsch, Ulrich; Postulka, Lars; Wolf, Bernd; Lang, Michael; Well, Natalija van; Ritter, Franz; Krellner, Cornelius; Assmus, Wolf [Physikalisches Institut, Goethe-University Frankfurt (Germany)

    2015-07-01

    The system Cs{sub 2}CuCl{sub 4-x}Br{sub x} (0 ≤ x ≤ 4) is a quasi-two-dimensional Heisenberg antiferromagnet with a triangular in-plane arrangement of the spin-spin couplings. The ratio J{sup '}/J of the corresponding coupling constants determines the degree of frustration in the system and has been found to be 0.34 (x = 0) and 0.74 (x = 4) for the border compounds. One may ask whether for some intermediate Br concentration an even higher degree of frustration can be reached. Indeed, some indications have been reported by Ono et al. Here, we present specific heat C and susceptibility χ measurements below 1 K in magnetic fields B up to 13.5 T for the intermediate compound Cs{sub 2}CuCl{sub 2}Br{sub 2}, which, due to site-selective substitution, shows a well-ordered halide sublattice. Indications for an antiferromagnetic transition are observed around 90 mK for B = 0. A small field of B = 0.14 T is sufficient to fully suppress this anomaly. Taking into account the high saturation field of about 20 T, extrapolated from χ(T = const, B) scans at low temperatures, this small ordered region in the B-T plane clearly indicates a high degree of frustration in Cs{sub 2}CuCl{sub 2}Br{sub 2}.

  15. Critical Analysis on the Structural and Magnetic Properties of Bulk and Nanocrystalline Cu-Fe-O

    Directory of Open Access Journals (Sweden)

    D. Paul Joseph

    2010-01-01

    Full Text Available Nanocrystalline and bulk samples of “Fe”-doped CuO were prepared by coprecipitation and ceramic methods. Structural and compositional analyses were performed using X-ray diffraction, SEM, and EDAX. Traces of secondary phases such as CuFe2O4, Fe3O4, and α-Fe2O3 having peaks very close to that of the host CuO were identified from the Rietveld profile analysis and the SAED pattern of bulk and nanocrystalline Cu0.98Fe0.02O samples. Vibrating Sample Magnetometer (VSM measurements show hysteresis at 300 K for all the samples. The ferrimagnetic Neel transition temperature ( was found to be around 465°C irrespective of the content of “Fe”, which is close to the value of cubic CuFe2O4. High-pressure X-Ray diffraction studies were performed on 2% “Fe”-doped bulk CuO using synchrotron radiation. From the absence of any strong new peaks at high pressure, it is evident that the secondary phases if present could be less than the level of detection. Cu2O, which is diamagnetic by nature, was also doped with 1% of “Fe” and was found to show paramagnetic behavior in contrast to the “Fe” doped CuO. Hence the possibility of intrinsic magnetization of “Fe”-doped CuO apart from the secondary phases is discussed based on the magnetization and charge state of “Fe” and the host into which it is substituted.

  16. Photoluminescent mixed ligand complexes of CuX (X = Cl, Br, I) with PPh3 and a polydentate imino-pyridyl ligand - Syntheses, structural variations and catalytic property

    Science.gov (United States)

    Ghorai, Anupam; Mondal, Jahangir; Patra, Goutam K.

    2015-10-01

    Three ternary copper(I) complexes [CuI2Cl2(L1)(PPh3)4] (1), [CuI2Br2(L1) (PPh3)4] (2) and [CuI2(μ-I)2 (μ-L1) (PPh3)2]n (3) have been prepared by reactions of CuX (X = Cl, Br and I) with PPh3 and the polydentate imino-pyridyl ligand L1. These complexes have been characterized by elemental analysis, IR, UV-Vis, NMR and X-ray crystallography. From single crystal structural analysis it has been found that complexes 1 and 2 are homo-dinuclear having non-bridging halide ions whereas complex 3 is a 1-D zig-zag co-ordination polymer containing bridged iodide ions. Complexes 1, 2 and 3 are photoluminescent at room temperature in chloroform whereas ligand L1 is non-emissive. The E½ values of the CuIsbnd CuII couple of 1, 2 and 3 are 0.98 V, 0.92 V and 0.42 V respectively (vs Ag/AgCl in 1 M KCl, scan rate 100 mV s-1). All three complexes function as effective catalysts for the synthesis of 2-substituted benzoxazoles.

  17. Physical, Optical and Electron paramagnetic resonance studies of PbBr2-PbO-B2O3 glasses containing Cu2+ ions

    Science.gov (United States)

    Sekhar, K. Chandra; Hameed, Abdul; Chary, M. Narasimha; Shareefuddin, Md

    2016-09-01

    The glasses with the composition PbBr2-PbO-B2O3 glasses containing Cu2+ ions were prepared by melt quenching technique. X-ray diffractograms revealed the amorphous nature of the glasses. Density and molar volume were determined. Density is found to decrease while the molar volume increases with increase of PbBr2 content. The optical absorption spectra exhibited a broad band corresponding to the d- d transition of Cu2+ ion. From optical absorption spectra Eopt and Urbach energies were determined. Electron Paramagnetic Resonance (EPR) studies were carried out by introducing Cu2+ as the spin probe. Glasses containing transition metal(TM) ions such as Cu2+ give the information about the structure and the site symmetry around the TM ions. EPR spectra of all the glass samples were recorded at X-band frequencies. From the EPR spectra spin-Hamiltonian parameters were evaluated. It was observed that g∥ >g±>ge (2.0023) and A∥>A±. From this values it is concluded that the ground state of Cu2+ is dx2-y2 (2B1g) and the site symmetry around Cu2+ ion is tetragonally distorted octahedral. From the EPR and Optical data bonding coefficients were evaluated. The in plane o-bonding(α2) is moderately ionic while out of plane 7t-bonding(β2) and in plane 7t-bonding(β1 2) are ionic nature

  18. Oxidation of two ternary Fe-Cu-5Al alloys in 1×105 Pa pure oxygen at 700 ℃

    Institute of Scientific and Technical Information of China (English)

    XIANG Jun-huai; NIU Yan; WU Wei-tao; LIU Guo-dong

    2006-01-01

    The oxidation of two two-phase ternary Fe-Cu-Al alloys containing about 5% Al(mole fraction),one Fe-rich and one Cu-rich,were studied at 700 ℃ in 1×105 Pa pure oxygen. The Fe-rich alloy (Fe-15Cu-5Al) shows two quasi-parabolic stages,with a large increase of the parabolic rate constant after about 4 h. The presence of 5% Al does not change greatly the oxidation rate of Fe-15Cu-5Al with respect to a binary Fe-Cu alloy of similar composition,which was quite different from the situation of the same alloys oxidized at 800 ℃. Oxidation of Fe-15Cu-5Al at 700 ℃ produced an outer layer of iron oxides and an inner layer containing a mixture of copper metal,iron and aluminium oxide. On the contrary,the Cu-rich Fe-85Cu-5Al alloy presents a rather irregular kinetic behavior,with formation of an inner continuous alumina thin layer and a rather irregular outer layer. The outer layer with a rather irregular thickness was mainly composed of a matrix of copper oxides plus some aluminium and iron oxides presenting in the deep part of the layer at certain locations. As a result of the formation of a protective alumina layer,the presence of 5% Al greatly reduced the oxidation rate of Fe-85Cu-5Al with respect to a binary Fe-Cu alloy of similar composition,which was also quite different from the situation of the same alloys oxidized at 800 ℃. Moreover,the oxidation rate at 700 ℃ of the Fe-85Cu-5Al alloy was much lower than that of Fe-15Cu-5Al alloy due to the same reason..

  19. First principles calculation of stable structure and adhesive strength of plated Ni/Fe(100) or Cu/Fe(100) interfaces

    Institute of Scientific and Technical Information of China (English)

    Ryota NAKANISHI; Koji SUEOKA; Seiji SHIBA; Makoto HINO; Koji MURAKAMI; Ken MURAOKA

    2009-01-01

    A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed. Ni or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) substrate. Other calculations showed that the interfaces of Ni (5 atomic layers)/Fe(100) (5 layers) or Cu (5 atomic layers)/Fe(100) (5 layers) had square lattices. The orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100), Ni[011]//Fe[010], and Similar results were obtained for Cu/Fe(100) interfaces. This structure was supported by TEM analysis of plated Ni layer on Fe(100) surfaces. The adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) interface. The experimental results of Hull cell iron plated with Ni or Cu supported the results of the calculation. These results indicate that the first principles calculation, which deals with the ideal interface at the atomic scale, has the potential to evaluate the adhesion strength of metallic material interfaces.

  20. Quantum Monte Carlo simulation of antiferromagnetic spin ladder (C5H12N)2CuBr4

    Science.gov (United States)

    Freitas, Augusto S.

    2016-07-01

    In this paper I present a Quantum Monte Carlo (QMC) study of the magnetic properties of an antiferromagnetic spin ladder (C5H12N)2CuBr4. This compound is the prototype of the Heisenberg model for a two leg spin ladder in the presence of an external magnetic field. The susceptibility phase diagram has a rounded peak in the vicinity of T=7.4 K, obeys Troyer's law for low temperatures, and Curie's law for high temperatures. I also study the susceptibility diagram in low temperatures and I found the spin gap Δ=9.26 K, in good concordance with the experimental value, 9.5 K. In high field, I present a diagram of magnetization as a function of temperature. In the vicinity of a critical field, Hci, the magnetization scales with T1/2 and this result was found also in the QMC simulation. In all the results, there is a very good concordance with the experimental data. I also show in this paper that the spin gap is null and the susceptibility is proportional to T for low temperatures when relatively high values of the ladders' coupling is taken in account.

  1. Electron spin resonance insight into broadband absorption of the Cu3Bi(SeO32O2Br metamagnet

    Directory of Open Access Journals (Sweden)

    A. Zorko

    2016-05-01

    Full Text Available Metamagnets, which exhibit a transition from a low-magnetization to a high-magnetization state induced by the applied magnetic field, have recently been highlighted as promising materials for controllable broadband absorption. Here we show results of a multifrequency electron spin resonance (ESR investigation of the Cu3Bi(SeO32O2Br planar metamagnet on the kagome lattice. Its mixed antiferromagnetic/ferromagnetic phase is stabilized in a finite range of applied fields around 0.8 T at low temperatures and is characterized by enhanced microwave absorption. The absorption signal is non-resonant and its boundaries correspond to two critical fields that determine the mixed phase. With decreasing temperature these increase like the sublattice magnetization of the antiferromagnetic phase and show no frequency dependence between 100 and 480 GHz. On the contrary, we find that the critical fields depend on the magnetic-field sweeping direction. In particular, the higher critical field, which corresponds to the transition from the mixed to the ferromagnetic phase, shows a pronounced hysteresis effect, while such a hysteresis is absent for the lower critical field. The observed hysteresis is enhanced at lower temperatures, which suggests that thermal fluctuations play an important role in destabilizing the highly absorbing mixed phase.

  2. Synthesis, Structure and Photoluminescent Properties of the 2D Coordination Polymers Based on Cu2Br2 Unit with Flexible Thioether%基于柔性硫醚与Cu2Br2单元二维配位聚合物的合成、结构和荧光性质

    Institute of Scientific and Technical Information of China (English)

    李冬青; 时文娟

    2009-01-01

    A complex [Cu2Br2(L)2]2 (1) (L=bis (2-pyrimidinylthio)methane) has been synthesized and structurally characterized. Complex 1 contains dinuclear Cu2Br2 units, which are linked by ditopic L to form a 2D layer structure with a 36-membered macrometallocycle. The adjacent layers are further connected through interpyrimidyl rings C-H strong green solid-state photoluminescence, due to metal-to-ligand charge-transfer (MLCT) at room temperature. CCDC: 711434.

  3. Recrystallization Behavior of CoCrCuFeNi High-Entropy Alloy

    Science.gov (United States)

    Park, Nokeun; Watanabe, Ikuto; Terada, Daisuke; Yokoyama, Yoshihiko; Liaw, Peter K.; Tsuji, Nobuhiro

    2015-04-01

    We investigated the recrystallization behavior of a cold-rolled CoCrCuFeNi high-entropy alloy (HEA). Two different face-centered cubic phases having different chemical compositions and lattice constants in the as-cast specimen have different chemical compositions: One phase was the Cu-lean matrix and the other was the Cu-rich second phase. The second phase remained even after a heat treatment at 1373 K (1100 °C) and Cu enriched more in the Cu-rich second phase. The calculated mixing enthalpies of both Cu-lean and Cu-rich phases in the as-cast and heat-treated specimens explained that Cu partitioning during the heat treatment decreased the mixing enthalpy in both phases. In the specimens 90 pct cold rolled and annealed at 923 K, 973 K, and 1073 K (650 °C, 700 °C, and 800 °C), recrystallization proceeded with increasing the annealing temperature, and ultrafine recrystallized grains with grain sizes around 1 μm could be obtained. The microhardness tended to decrease with increasing the fraction recrystallized, but it was found that the microhardness values of partially recrystallized specimens were much higher than those expected by a simple rule of mixture between the initial and cold-rolled specimens. The reason for the higher hardness was discussed based on the ultrafine grain size, sluggish diffusion expected in HEAs, and two-phase structure in the CoCrCuFeNi alloy.

  4. TPR and TPD studies of effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts

    Indian Academy of Sciences (India)

    Olusola O James; Biswajit Chowdhury; Sudip Maity

    2013-05-01

    Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe-Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3→Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe-Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe-Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

  5. Magnetically Recyclable Fe3O4@His@Cu Nanocatalyst for Degradation of Azo Dyes.

    Science.gov (United States)

    Kurtan, U; Amir, Md; Baykal, A; Sözeri, H; Toprak, M S

    2016-03-01

    Fe3O4@His@Cu magnetic recyclable nanocatalyst (MRCs) was synthesized by reflux method using L-histidine as linker. The composition, structure and magnetic property of the product were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and vibrating sample magnetometry (VSM). Powder XRD, FT-IR and EDAX results confirmed that the as-synthesized products has Fe3O4 with spinel structure and Cu nanoparticles with moderate crystallinity without any other impurities. The surface of the Fe3O4@His nanocomposite was covered by tiny Cu nanoparticles. We examine the catalytic activity of Fe3O4@His@Cu MRCs for the degradation of two azo dyes, methyl orange (MO) and methylene blue (MB) as well as their mixture. The reusability of the nanocatalyst was good and sustained even after 3 cycles. Therefore this innovated Fe3O4@His@Cu MRCs has a potential to be used for purification of waste water.

  6. Ca, Mg, Zn, Fe, Cu and Mn content of ass’s milk

    Directory of Open Access Journals (Sweden)

    Elisabetta Salimei

    2010-01-01

    Full Text Available The aim of this study was to determine Ca, Mg, Zn, Fe, Cu and Mn content of ass’s milk. Twenty four individual milk samples were collected from 4 lactating asses. During the experi- mental period milk samples were collected every 3 weeks interval, using a milking machine; asses were housed with the foals that were separated from the jennets 3 hours before milking. Milk was analysed for Ca, Mg, Zn, Fe, Cu and Mn content by atomic absorption spectrometry. The concentration mean (±SD of Ca Mg, Zn, Fe, and Cu were respectively 334.61±39.80, 58.46±8.43, 1.99±0.51, 1.15±0.52, 0.16±0.06 mg/kg. Mn was found only at trace level. Iron content of ass’s milk was the most variable ranging from 0.43 to 1.88 mg/kg. Correlation coefficients were positive and significant between Ca and Mg (r=0.63, Zn and Mg (r=0.45, Zn and Fe (r=0.49 and Zn and Cu (r=0.50. In this study, except for Fe, mean concentration of Ca, Mg, Zn, and Cu in ass’s milk was similar to those reported in literature for human milk.

  7. Room temperature ferromagnetism in Fe-doped CuO nanoparticles.

    Science.gov (United States)

    Layek, Samar; Verma, H C

    2013-03-01

    The pure and Fe-doped CuO nanoparticles of the series Cu(1-x)Fe(x)O (x = 0.00, 0.02, 0.04, 0.06 and 0.08) were successfully prepared by a simple low temperature sol-gel method using metal nitrates and citric acid. Rietveld refinement of the X-ray diffraction data showed that all the samples were single phase crystallized in monoclinic structure of space group C2/c with average crystallite size of about 25 nm and unit cell volume decreases with increasing iron doping concentration. TEM micrograph showed nearly spherical shaped agglomerated particles of 4% Fe-doped CuO with average diameter 26 nm. Pure CuO showed weak ferromagnetic behavior at room temperature with coercive field of 67 Oe. The ferromagnetic properties were greatly enhanced with Fe-doping in the CuO matrix. All the doped samples showed ferromagnetism at room temperature with a noticeable coercive field. Saturation magnetization increases with increasing Fe-doping, becomes highest for 4% doping then decreases for further doping which confirms that the ferromagnetism in these nanoparticles are intrinsic and are not resulting from any impurity phases. The ZFC and FC branches of the temperature dependent magnetization (measured in the range of 10-350 K by SQUID magnetometer) look like typical ferromagnetic nanoparticles and indicates that the ferromagnetic Curie temperature is above 350 K.

  8. Spectro-photometric determinations of Mn, Fe and Cu in aluminum master alloys

    Science.gov (United States)

    Rehan; Naveed, A.; Shan, A.; Afzal, M.; Saleem, J.; Noshad, M. A.

    2016-08-01

    Highly reliable, fast and cost effective Spectro-photometric methods have been developed for the determination of Mn, Fe & Cu in aluminum master alloys, based on the development of calibration curves being prepared via laboratory standards. The calibration curves are designed so as to induce maximum sensitivity and minimum instrumental error (Mn 1mg/100ml-2mg/100ml, Fe 0.01mg/100ml-0.2mg/100ml and Cu 2mg/100ml-10mg/ 100ml). The developed Spectro-photometric methods produce accurate results while analyzing Mn, Fe and Cu in certified reference materials. Particularly, these methods are suitable for all types of Al-Mn, Al-Fe and Al-Cu master alloys (5%, 10%, 50% etc. master alloys).Moreover, the sampling practices suggested herein include a reasonable amount of analytical sample, which truly represent the whole lot of a particular master alloy. Successive dilution technique was utilized to meet the calibration curve range. Furthermore, the workout methods were also found suitable for the analysis of said elements in ordinary aluminum alloys. However, it was observed that Cush owed a considerable interference with Fe, the later one may not be accurately measured in the presence of Cu greater than 0.01 %.

  9. Microstructure and corrosion resistance of AlCrFeCuCo high entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xing-Wu, E-mail: qiuxingwu@126.com [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China); Zhang, Yun-Peng; He, Li [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Liu, Chun-ge [Department of Transportation and Municipal Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China)

    2013-02-05

    Highlights: Black-Right-Pointing-Pointer We use a new method (laser cladding) to prepare high-entropy alloy. Black-Right-Pointing-Pointer We gained small microstructure under rapid solidification condition. Black-Right-Pointing-Pointer We studied corrosion resistance of AlCrFeCuCo high-entropy alloy in two different liquids. - Abstract: The AlCrFeCuCo high-entropy alloys were prepared by the laser cladding method. The microstructure and corrosion resistance property of AlCrFeCuCo high-entropy alloy were researched by scanning electron microscopy, X-ray diffraction and electrochemical workstation. The results show that, under the rapid solidification small microstructure gained, the morphology of AlCrFeCuCo high entropy alloy is simple, the phase mainly compose of FCC and BCC; elements segregated in the alloys; the alloy shows excellent corrosion resistance, along with the increase of the scanning speed, alloy corrosion resistance performance shows a enhancement in the first and then weakened trend. The corrosion resistance performance of AlCrFeCuCo high-entropy alloys in 1 mol/L NaCl solution is better than in 0.5 mol/L H{sub 2}SO{sub 4} solution.

  10. Determination of metals (As, Cu, Fe, and Zn in two fish species from the Miankaleh wetland

    Directory of Open Access Journals (Sweden)

    Alipour Hossein

    2016-06-01

    Full Text Available The objective of this study was to determine the concentrations As, Cu, Fe, and Zn in the livers, gills, and muscles of vobla or Caspian roach, Rutilus caspicus (Yakovlev, and bighead goby, Neogobius gorlap (Iljin, from the Miankaleh wetland. The results showed that metal accumulation in the liver tissues was higher than in the gills and muscles for all metals, and Fe concentration was higher than Zn, Cu, and As in all the tissues studied. The concentrations of As, Cu, Fe, and Zn in the livers, gills, and muscles of bighead goby were higher than in vobla tissues, except for concentrations of As in the muscles. Fe, Cu, and Zn concentrations in the muscles were below the maximum permissible limit of the WHO and the FAO for both species, but the concentration of As in the muscles of both species exceeded the permissible limit proposed by the FAO; thus, human consumption should be limited. The levels of the other metals (Fe, Cu and Zn were completely safe.

  11. Simple electrodepositing of CoFe/Cu multilayers: Effect of ferromagnetic layer thicknesses

    Science.gov (United States)

    Tekgül, Atakan; Alper, Mürsel; Kockar, Hakan

    2017-01-01

    The CoFe/Cu magnetic multilayers were produced by changing CoFe ferromagnetic layers from 3 nm to 10 nm using electrodeposition. By now, the thinnest Cu (0.5 nm) layer thicknesses were used to see whether the GMR effect in the multilayers can be obtained or not since the pinning of non-magnetic layer between the ferromagnetic layers is required. For the proper depositions, the cyclic voltammograms was used, and the current-time transients were obtained. The Cu and CoFe layers were deposited at a cathode potential of -0.3 and -1.5 V with respect to saturated calomel electrode, respectively. From the XRD patterns, the multilayers were shown to be fcc crystal structures. For the magnetization measurements, saturation magnetization increases from 160 to 600 kA/m from 3 to 8 nm ferromagnetic layer thicknesses. And, the coercivity values increase until the 8 nm of the CoFe layer thickness. It is seen that the thin Cu layer (fixed at 0.5 nm) and pinholes support the random magnetization orientation and thus all multilayers exhibited the giant magnetoresistance (GMR) effect, and the highest GMR value was observed about 5.5%. And, the variation of GMR field sensitivity was calculated. The results show that the GMR and GMR sensitivity are compatible among the multilayers. The CoFe/Cu magnetic multilayers having GMR properties are used in GMR sensors and hard disk drive of the nano-technological devices.

  12. Influence of structural parameters on magnetoresistive properties of CuFeNi melt spun ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Cazottes, S., E-mail: sophie.cazottes@etu.univ-rouen.fr [Groupe de Physique des Materiaux (GPM), Universite de Rouen, UMR CNRS 6634, Site Universitaire du Madrillet, Avenue de l' Universite, BP 12, 76801 Saint-Etienne du Rouvray Cedex (France); Danoix, F.; Fnidiki, A.; Lemarchand, D. [Groupe de Physique des Materiaux (GPM), Universite de Rouen, UMR CNRS 6634, Site Universitaire du Madrillet, Avenue de l' Universite, BP 12, 76801 Saint-Etienne du Rouvray Cedex (France); Baricco, M. [Dipartimento di Chimica IFM and NIS/INSTM, Universita' di Torino, Via P. Giuria 9, 10125 Torino (Italy)

    2009-04-15

    The microstructure of Cu{sub 80}Fe{sub 10}Ni{sub 10} (at%) granular ribbon was investigated by means of atom probe tomography (APT). A granular system is composed of magnetic precipitates embedded in a non-magnetic matrix. In this ribbon, the magnetic precipitates have a diameter smaller than 5 nm in the as-spun state, and their crystallographic structure is very similar to the one of the matrix, which makes it difficult to characterize them using conventional techniques. Those data are of great importance to understand the magnetic and the transport behaviour of these ribbons. Using atom probe tomography, a 3D reconstruction of the microstructure of the as-spun and annealed ribbons was achieved and a precise characterization of the compositions of the two phases and of the composition profile at interfaces was carried out. In the as-spun state the composition of the matrix is Cu{sub 89}Fe{sub 3}Ni{sub 8}, the one of the precipitates is Cu{sub 30}Fe{sub 40}Ni{sub 30}. Upon annealing, the precipitates get enriched in iron. After annealing at 600 {sup o}C for 24 h, the measured compositions are close to the one predicted by Thermocalc, with Cu{sub 94}Fe{sub 1}Ni{sub 5} for the matrix and Cu{sub 5}Fe{sub 64}Ni{sub 31} for the precipitates.

  13. Influence of structural parameters on magnetoresistive properties of CuFeNi melt spun ribbons.

    Science.gov (United States)

    Cazottes, S; Danoix, F; Fnidiki, A; Lemarchand, D; Baricco, M

    2009-04-01

    The microstructure of Cu(80)Fe(10)Ni(10) (at%) granular ribbon was investigated by means of atom probe tomography (APT). A granular system is composed of magnetic precipitates embedded in a non-magnetic matrix. In this ribbon, the magnetic precipitates have a diameter smaller than 5nm in the as-spun state, and their crystallographic structure is very similar to the one of the matrix, which makes it difficult to characterize them using conventional techniques. Those data are of great importance to understand the magnetic and the transport behaviour of these ribbons. Using atom probe tomography, a 3D reconstruction of the microstructure of the as-spun and annealed ribbons was achieved and a precise characterization of the compositions of the two phases and of the composition profile at interfaces was carried out. In the as-spun state the composition of the matrix is Cu(89)Fe(3)Ni(8), the one of the precipitates is Cu(30)Fe(40)Ni(30). Upon annealing, the precipitates get enriched in iron. After annealing at 600 degrees C for 24h, the measured compositions are close to the one predicted by Thermocalc, with Cu(94)Fe(1)Ni(5) for the matrix and Cu(5)Fe(64)Ni(31) for the precipitates.

  14. Magnetic order tuned by Cu substitution in Fe1.1-zCuzTe

    Science.gov (United States)

    Wen, Jinsheng; Xu, Zhijun; Xu, Guangyong; Lumsden, M. D.; Valdivia, P. N.; Bourret-Courchesne, E.; Gu, Genda; Lee, Dung-Hai; Tranquada, J. M.; Birgeneau, R. J.

    2012-07-01

    We study the effects of Cu substitution in Fe1.1Te, the nonsuperconducting parent compound of the iron-based superconductor, Fe1+yTe1-xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at ˜60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.5-δ, 0, 0.5) with δ being the incommensurability of 0.02, and correlation length of 12 Å along the a axis and 9 Å along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first-order transition to a long-range almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has a large effect on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.

  15. Magnetic orders tuned by Cu substitution in Fe1.1 zCuzTe

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Jinsheng [University of California, Berkeley; Xu, Zhijun [Brookhaven National Laboratory (BNL); Xu, Guangyong [Brookhaven National Laboratory (BNL); Lumsden, Mark D [ORNL; Valdivia, P. N. [University of California, Berkeley; Bourret-Courchesne, E. D. [Lawrence Berkeley National Laboratory (LBNL); Gu, Genda [Brookhaven National Laboratory (BNL); Lee, Dunghai [University of California, Berkeley & LBNL; Tranquada, John M. [Brookhaven National Laboratory (BNL); Birgeneau, R. J. [University of California, Berkeley

    2012-01-01

    We study the effects of Cu substitution in Fe1.1Te, the non-superconducting parent compound of the iron-based superconductor, Fe1+yTe1 xSex, utilizing neutron scattering techniques. It is found that the structural and magnetic transitions, which occur at 60 K without Cu, are monotonically depressed with increasing Cu content. By 10% Cu for Fe, the structural transition is hardly detectable, and the system becomes a spin glass below 22 K, with a slightly incommensurate ordering wave vector of (0.48, 0, 0.5), and correlation length of 12 A along the a axis and 9 A along the c axis. With 4% Cu, both transition temperatures are at 41 K, though short-range incommensurate order at (0.42, 0, 0.5) is present at 60 K. With further cooling, the incommensurability decreases linearly with temperature down to 37 K, below which there is a first order transition to a longrange almost-commensurate antiferromagnetic structure. A spin anisotropy gap of 4.5 meV is also observed in this compound. Our results show that the weakly magnetic Cu has large effects on the magnetic correlations; it is suggested that this is caused by the frustration of the exchange interactions between the coupled Fe spins.

  16. Synthesis of 1H-indazoles and 1H-pyrazoles via FeBr3/O2 mediated intramolecular C-H amination.

    Science.gov (United States)

    Zhang, Tianshui; Bao, Weiliang

    2013-02-01

    A new synthesis of substituted 1H-indazoles and 1H-pyrazoles from arylhydrazones via FeBr(3)/O(2) mediated C-H activation/C-N bond formation reactions is reported. The corresponding 1,3-diaryl-substituted indazoles and trisubstituted pyrazoles were obtained in moderate to excellent yields under mild conditions.

  17.  Pressure-induced Fe↔Cu cationic valence exchange and its structural consequences: High-pressure studies of delafossite CuFeO2

    Science.gov (United States)

    Xu, W. M.; Rozenberg, G. Kh.; Pasternak, M. P.; Kertzer, M.; Kurnosov, A.; Dubrovinsky, L. S.; Pascarelli, S.; Munoz, M.; Vaccari, M.; Hanfland, M.; Jeanloz, R.

    2010-03-01

    The present high-pressure studies of CuFeO2 to 30 GPa using x-ray diffraction, along with F57e Mössbauer and Fe and CuK -edge x-ray absorption spectroscopy methods, reveal a sequence of intricate structural/electronic-magnetic pressure-induced transitions. The low-pressure R3¯m structure (0-18 GPa) is composed of sheets of FeS=5/23+ ions alternating with layers of O-CuS=01+-O dumbbells, the latter oriented along the c axis. This structure is characterized by an unusual positive d(c/a)/dP . At 18 GPa a structural transition takes place to a more isotropic C2/c structure with the O-CuS=01+-O axis tilted 28° from the c axis and with negative d(c/a)/dP . This transition corroborates with the onset of long-range antiferromagnetic order. Starting at ˜23GPa , with an initial volume reduction in ˜|ΔV/V0|=0.16 , the Cu-Fe bands overlap and this leads to a (CuS=01+FeS=5/23+)→(CuS=1/22+FeS=22+) interionic valence exchange in about 1/3 of the C2/c-CuFeO2 at 27 GPa. As a result: (i) the Cu2+-O becomes fourfold coordinated and is in a new crystallographic structure with space group P3¯m , and (ii) the Néel temperature increases above twofold [TN(CuS=1/22+FeS=22+)≈2.2TN(CuS=01+FeS=5/23+)] . This sequence of transitions is reversible with minimal hysteresis.

  18. Synthesis of a clinoptilolite-Fe system with high Cu sorption capacity.

    Science.gov (United States)

    Doula, Maria K

    2007-03-01

    An iron oxide-clinoptilolite system was synthesized by adding natural clinoptilolite in an iron nitrate solution under strongly basic condition. The newly synthesized material has a red-brown color. A combination of XRD, FTIR and EPR spectroscopies, as well as specific surface area measurements and TG/DSC thermal analyses provided information on the type of Fe species located on the zeolite surface. Clinoptilolite seems to maintain its structure, while Fe(3+) species are in a symmetric environment (Th or Oh). The new material has a noteworthy high value of specific surface area (151 m(2)g(-1)) and is fully iron exchanged (Fe/Al=1.23). Differences in FTIR and TG/DSC spectrograms between the Fe-Clin system and untreated Clin were reported and explained. According to Cu adsorption/desorption experiments, carried out after the synthesis and characterization procedures, the Fe-Clin system is a promising new material since it adsorbs significantly larger Cu concentrations than clinoptilolite. This fact is owed to its high specific surface area and to its high negative surface charge. Desorption of Cu was also examined and it was observed that the Fe-Clin system desorbs smaller Cu amounts than untreated clinoptilolite.

  19. Interfacial tension studies between Fe-Cu-Ni sulfide and halo-norilsk basalt slag system

    Institute of Scientific and Technical Information of China (English)

    SU Shangguo; Jim Mungall; WANG Jian; GENG Ke

    2005-01-01

    The interfacial tension of the matte/halo-Norilsk basalt slag systems of FeS-Cu2S-Ni3S2 and FeO-FeS were investigated using the sessile drop technique. The results indicate that interfacial tension decreases with increasing copper and nickel contents in the matte of FeS-Cu2S-Ni3S2 system while it increases with increasing oxygen content in the matte of FeO-FeS system. It is inferred from these results that two conditions are critical for the formation of giant Cu-Ni sulfide deposits. One is that mafic-ultramafic parent magma of sulfide deposits should be rich in copper and nickel where due to the low interfacial tension, it is difficult to form sulfide droplet in the early stage of magma evolution. In other words, sulfide liquid conglomeration occurs more difficultly. The other condition is that the magma emplacement should be shallow; and a lot of faults occur in the magma emplacement field. Since oxygen content is high in the environment, interfacial tension is high, which helps sulfide liquid conglomeration and consequently Cu-Ni sulfide deposits form.

  20. Preparation and characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu

    OpenAIRE

    Corredor, Edna C.

    2012-01-01

    El objetivo del trabajo realizado en esta tesis titulada: Preparation and magnetic characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu es establecer relaciones entre las propiedades magnéticas de sistemas nanoestructurados y sus dimensiones físicas o factores estructurales que aparecen al reducirse la dimensión espacial a dos, en el caso de películas delgadas, y a una en el caso de elementos patronados. Los sistemas objeto de estudio se caracterizan por se...

  1. Preparation and characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu

    OpenAIRE

    Corredor Vega, Edna Consuelo; Ciria Remacha, Miguel Ángel; Arnaudas Pontaque, José Ignacio

    2013-01-01

    El objetivo del trabajo realizado en esta tesis titulada: Preparation and magnetic characterization of epitaxial thin films and patterned nanostructures of Ni/Cu and Fe/Cu es establecer relaciones entre las propiedades magnéticas de sistemas nanoestructurados y sus dimensiones físicas o factores estructurales que aparecen al reducirse la dimensión espacial a dos, en el caso de películas delgadas, y a una en el caso de elementos patronados. Los sistemas objeto de estudio se caracterizan por se...

  2. The Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8} compounds: Crystal structure and electroanalytical application

    Energy Technology Data Exchange (ETDEWEB)

    Kormosh, Zh., E-mail: kormosh@univer.lutsk.ua [Department of Analytical Chemistry and Eco-technology, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine); Fedorchuk, A. [Department of Inorganic and Organic Chemistry, Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska St., 79010 Lviv (Ukraine); Wojciechowski, K. [Department of Inorganic Chemistry, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Cracow (Poland); Tataryn, N. [Department of Analytical Chemistry and Eco-technology, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine); Parasyuk, O. [Department of Inorganic and Physical Chemistry, Volyn National University, 13 Voli Ave, 43025 Lutsk (Ukraine)

    2011-04-08

    The Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8} compounds were produced by solid-state synthesis. The crystal structure of the quaternary phases was investigated by X-ray powder method. The compounds are described in the thiospinel structure (space group Fd3-bar m) with the unit cell parameters a = 1.00099(1) nm (Cu{sub 2}FeTi{sub 3}S{sub 8}) and a = 1.03837(2) nm (Cu{sub 2}FeZr{sub 3}S{sub 8}). The atomic parameters were calculated in the isotropic approximation (R{sub I} = 0.0496 and R{sub I} = 0.0422 for Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8}, respectively). Iron(III)-selective electrodes were prepared using the chalcogenide compounds Cu{sub 2}FeTi{sub 3}S{sub 8} and Cu{sub 2}FeZr{sub 3}S{sub 8}. The electrode function slopes are 52.7 mV/pC for Cu{sub 2}FeTi{sub 3}S{sub 8} and 66.2 mV/pC for Cu{sub 2}FeZr{sub 3}S{sub 8}, the detection limits are 1 x 10{sup -5} M and 2 x 10{sup -5} M respectively. The prepared electrochemical sensors are not sensitive to Cd{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Mg{sup 2+}, Cr{sup 3+}, and Fe{sup 2+} ions, and were tested in the potentiometric titration of Fe(III) with EDTA solution.

  3. Magnetic ordering of Fe atoms in the YBa2(Cu/0. 95/Fe/0. 05/)3O(7. 01) superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Liubutin, I.S.; Terziev, V.G.; Morozov, O.N. (Institut Kristallografii, Moscow (USSR))

    1990-11-01

    Moessbauer spectroscopy detected the magnetic ordering of Fe atoms in YBa2(Cu/0.95/Fe/0.05/)3O(y) in both the superconducting and the nonsuperconducting states. It is shown that, in the superconducting sample, the superconductivity coexists with magnetic ordering of the Fe atoms in Cu1 nodes. In the nonsuperconducting sample, the Fe atoms in the Cu1 nodes have a magnetic-ordering point (20 K) which is reduced by 10 K upon transition to the superconducting state. 15 refs.

  4. Facile synthesis of Fe-incorporated CuO nanoarrays with enhanced electrochemical performance for lithium ion full batteries

    Energy Technology Data Exchange (ETDEWEB)

    Heng, Bojun [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Department of Applied Physics, Wuhan University of Science and Technology, Wuhan, 430065 (China); Qing, Chen; Wang, Hai; Sun, Daming; Wang, Bixiao [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China); Tang, Yiwen, E-mail: ywtang@phy.ccnu.edu.cn [Institute of Nano-science and Technology, Central-China Normal University, Wuhan, 430079 (China)

    2015-11-15

    CuO nanoarrays (CNAs) and Fe-incorporated CuO nanoarrays (FCNAs) were fabricated by hydrothermal method. Addition of Fe salt to the reaction mixture allowed the introduction of iron oxide onto the CNAs surface, which was characterized by XPS and HRTEM. Introducing Fe ion into reaction precursor significantly affected not only the morphologies of as-prepared products but also their electrochemical performance as anode for lithium ion full battery. The FCNAs electrodes showed higher specific capacity and better capacity retention at different current densities than that of CNAs. - Highlights: • Fe-incorporated CuO nanoarrays were fabricated by hydrothermal method. • Fe salt in reaction mixture leads to iron oxides forming on the surface of CuO. • Fe-incorporating improves the lithium ion battery performance of CuO anodes.

  5. Exposure studies of core-shell Fe/Fe(3)O(4) and Cu/CuO NPs to lettuce (Lactuca sativa) plants: Are they a potential physiological and nutritional hazard?

    Science.gov (United States)

    Trujillo-Reyes, J; Majumdar, S; Botez, C E; Peralta-Videa, J R; Gardea-Torresdey, J L

    2014-02-28

    Iron and copper nanomaterials are widely used in environmental remediation and agriculture. However, their effects on physiological parameters and nutritional quality of terrestrial plants such as lettuce (Lactuca sativa) are still unknown. In this research, 18-day-old hydroponically grown lettuce seedlings were treated for 15 days with core-shell nanoscale materials (Fe/Fe(3)O(4), Cu/CuO) at 10 and 20mg/L, and FeSO(4)·7H(2)O and CuSO(4)·5H(2)O at 10mg/L. At harvest, Fe, Cu, micro and macronutrients were determined by ICP-OES. Also, we evaluated chlorophyll content, plant growth, and catalase (CAT) and ascorbate peroxidase (APX) activities. Our results showed that iron ions/NPs did not affect the physiological parameters with respect to water control. Conversely, Cu ions/NPs reduced water content, root length, and dry biomass of the lettuce plants. ICP-OES results showed that nano-Cu/CuO treatments produced significant accumulation of Cu in roots compared to the CuSO(4)·5H(2)O treatment. In roots, all Cu treatments increased CAT activity but decreased APX activity. In addition, relative to the control, nano-Cu/CuO altered the nutritional quality of lettuce, since the treated plants had significantly more Cu, Al and S but less Mn, P, Ca, and Mg.

  6. Characterization of transparent superconductivity Fe-doped CuCrO2 delafossite oxide

    Science.gov (United States)

    Taddee, Chutirat; Kamwanna, Teerasak; Amornkitbamrung, Vittaya

    2016-09-01

    Delafossite CuCr1-xFexO2 (0.0 ≤ x ≤ 0.15) semiconductors were synthesized using a self-combustion urea nitrate process. The effects of Fe concentration on its microstructural, optical, magnetic, and electrical properties were investigated. X-ray diffraction (XRD) analysis results revealed the delafossite structure in all the samples. The lattice spacing of CuCr1-xFexO2 slightly increased with increasing substitution of Fe at the Cr sites. The optical properties measured at room temperature using UV-visible spectroscopy showed a weak absorbability in the visible light and near IR regions. The corresponding direct optical band gap was about 3.61 eV, exhibiting transparency in the visible region. The magnetic hysteresis loop measurements showed that the Fe-doped CuCrO2 samples exhibited ferromagnetic behavior at room temperature. This indicated that the substitution of Fe3+ for Cr3+ produced a mixed effect on the magnetic properties of CuCrO2 delafossite oxide. The temperature dependent resistivity measurements clearly revealed the presence of superconductivity in the CuCr1-xFexO2 with a superconducting transition up to 118 K.

  7. Modeling and analysis of soybean (Glycine max. L Cu/Zn, Mn and Fe superoxide dismutases

    Directory of Open Access Journals (Sweden)

    V. Ramana Gopavajhula

    2013-01-01

    Full Text Available Superoxide dismutase (SOD, EC 1.15.1.1 is an important metal-containing antioxidant enzyme that provides the first line of defense against toxic superoxide radicals by catalyzing their dismutation to oxygen and hydrogen peroxide. SOD is classified into four metalloprotein isoforms, namely, Cu/Zn SOD, Mn SOD, Ni SOD and Fe SOD. The structural models of soybean SOD isoforms have not yet been solved. In this study, we describe structural models for soybean Cu/Zn SOD, Mn SOD and Fe SOD and provide insights into the molecular function of this metal-binding enzyme in improving tolerance to oxidative stress in plants.

  8. Chemical effect on the K shell fluorescence yield of Fe, Mn, Co, Cr and Cu compounds

    Indian Academy of Sciences (India)

    U Turgut

    2004-11-01

    Chemical effects on the K shell fluorescence yields of Fe, Mn, Co, Cr and Cu compounds were investigated. Samples were excited using 59.5 keV energy photons from a 241Am radioisotope source. K X-rays emitted by samples were counted by a Si(Li) detector with a resolution 160 eV at 5.9 keV. Chemical effects on the K shell fluorescence yields (K) for Fe, Mn, Co, Cr and Cu compounds were observed. The values are compared with theoretical, semiempirical fit and experimental ones for the pure elements.

  9. Celdas galvánicas. Montaje y comprobación de la celda constituida por los pares Fe(III)/Fe(II)y Cu(II)/Cu.

    OpenAIRE

    Milla González, Miguel

    2013-01-01

    Se dispone de disoluciones de sulfato de cobre(II), sulfato de hierro(II) y nitrato de Fe(III), de un potenciómetro, un puente salino y electrodos de Cu y de grafito. Con las disoluciones citadas, montar una celda galvánica y medir su potencial. Son posibles todas las combinaciones tanto en el compartimento anódico como en el catódico.

  10. Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

    Science.gov (United States)

    Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

    2013-10-01

    A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  11. Effects of Cu Layer Width on the Giant Magneto-impedance Effect in Sandwich FeCuNbCrSiB/Cu/FeCuNbCrSiB Films With a Meander Line Structure%Cu层宽度对弯曲型三明治结构FeCuNbCrSiB/Cu/FeCuNbCrSiB多层膜巨磁阻抗效应的影响

    Institute of Scientific and Technical Information of China (English)

    张亚民; 陈吉安; 周勇; 丁文; 王明军; 高孝裕; 周志敏

    2005-01-01

    采用射频磁控溅射方法和微细加工工艺制备了不同Cu层宽度的弯曲型三明治结构的FeCuNbCrSiB/Cu/FeCuNbCrSiB多层膜,在频率1~40MHz下研究了Cu层宽度对多层膜的纵向和横向巨磁阻抗效应的影响.结果表明,弯曲型三明治结构多层膜的巨磁阻抗率随Cu层宽度的变化具有显著的变化,在频率10MHz、磁场12kA/m下,当Cu层宽度为0.4mm时,纵向、横向巨磁阻抗率分别达-57%、-65%.

  12. Crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4 from X-ray powder diffraction

    Indian Academy of Sciences (India)

    G E Delgado; A J Mora; P Grima-Gallardo; M Muñoz; S Durán; M Quintero; J M Briceño

    2015-08-01

    The crystal structure of the quaternary compounds CuFe2AlSe4 and CuFe2GaSe4, belonging to the system I–II2–III–VI4, were characterized using X-ray powder diffraction data. Both compounds crystallize in the tetragonal space group I42m (No. 121), = 2, with unit cell parameters = 5.609(1) Å, = 10.963(2) Å for CuFe2AlSe4 and = 5.6165(3) Å, = 11.075(1) Å for CuFe2GaSe4. These compounds are isostructural with CuFe2InSe4, and have a normal adamantane stannite structure.

  13. Induced Ferromagnetism at BiFeO3/YBa2Cu3O7 Interfaces

    OpenAIRE

    Zhu, Jian-Xin; WEN, XIAO-DONG; Haraldsen, J. T.; He, Mi; C. Panagopoulos; Chia, Elbert E. M.

    2014-01-01

    Transition metal oxides (TMOs) exhibit many emergent phenomena ranging from high-temperature superconductivity and giant magnetoresistance to magnetism and ferroelectricity. In addition, when TMOs are interfaced with each other, new functionalities can arise, which are absent in individual components. Here, we report results from first-principles calculations on the magnetism at the BiFeO3/YBa2Cu3O7 interfaces. By comparing the total energy for various magnetic spin configurations inside BiFe...

  14. Novel La(Fe,Si){sub 13}/Cu composites for magnetic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lyubina, Julia; Hannemann, Ullrich; Ryan, Mary P. [Department of Materials, Imperial College London, London, SW7 2AZ (United Kingdom); Cohen, Lesley F. [Department of Physics, Imperial College London, London, SW7 2AZ (United Kingdom)

    2012-11-15

    An approach to engineering magnetic refrigerant materials with defined thermal transport properties is demonstrated using the example of high magnetocaloric performance La-Fe-Si alloys. A tunability of up to 300% of the thermal conductivity can be achieved in composites consisting of a La(Fe,Si){sub 13} compound and Cu prepared by electroless copper plating without compromising the magnitude of the magnetocaloric effect. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Structural and magnetic properties of FeMnx chains (x =1 -6 ) supported on Cu2N /Cu (100)

    Science.gov (United States)

    Choi, Deung-Jang; Robles, Roberto; Gauyacq, Jean-Pierre; Ternes, Markus; Loth, Sebastian; Lorente, Nicolás

    2016-08-01

    Heterogeneous atomic magnetic chains are built by atom manipulation on a Cu2N /Cu (100) substrate. Their magnetic properties are studied and rationalized by a combined scanning tunneling microscopy (STM) and density functional theory (DFT) work completed by model Hamiltonian studies. The chains are built using Fe and Mn atoms ontop of the Cu atoms along the N rows of the Cu2N surface. Here, we present results for FeMnx chains (x =1 -6 ) emphasizing the evolution of the geometrical, electronic, and magnetic properties with chain size. By fitting our results to a Heisenberg Hamiltonian we have studied the exchange-coupling matrix elements J for different chains. For the shorter chains, x ≤2 , we have included spin-orbit effects in the DFT calculations, extracting the magnetic anisotropy energy. Our results are also fitted to a simple anisotropic spin Hamiltonian and we have extracted values for the longitudinal-anisotropy D and transversal-anisotropy E constants. These parameters together with the values for J allow us to compute the magnetic excitation energies of the system and to compare them with the experimental data.

  16. Charge compensation and magnetic properties in Sr and Cu doped La-Fe perovskites

    Directory of Open Access Journals (Sweden)

    de Julián Fernández C.

    2013-01-01

    Full Text Available Orthorhombic lanthanum orthoferrites La0.8Sr0.2Fe1-yCuyO3-w (y = 0 and 0.10 have been studied using X-rays and neutron powder diffraction (XRPD and NPD, magnetization measurements and 57Fe Mössbauer spectroscopy. Rietveld refinements on XRPD and NPD data show that they adopt an orthorhombic ABO3 perovskite symmetry with La/Sr and Fe/Cu atoms randomly distributed on crystal A and B sites, respectively. The magnetic structure at room temperature is antiferromagnetic, with the Fe/Cu magnetic moments aligned along the a axis. Magnetization curves versus temperature show that the compounds exhibit an overall antiferromagnetic and a weak ferromagnetic behaviour in the range 5-298 K. 57Fe Mössbauer spectroscopy measurements indicate that Fe3+ and Fe5+ ions coexist in both compounds, and the relative percentage of Fe5+ is almost the same at 77 and 170 K, rejecting a charge disproportion mechanism.

  17. A GREENER SYNTHESIS OF CORE (FE, CU)-SHELL (AU, PT, PD AND AG) NANOCRYSTALS USING AQUEOUS VITAMIN C

    Science.gov (United States)

    A greener method to fabricate the novel core (Fe and Cu)-shell (noble metals) metal nanocrystals using aqueous ascorbic acid (vitamin C) is described. Transition metal salts such as Cu and Fe were reduced using ascorbic acid, a benign naturally available antioxidant, and then add...

  18. Studies on the interaction between 9-fluorenylmethyl chloroformate and Fe3+ and Cu2+ ions: Spectroscopic and theoretical calculation approach

    Science.gov (United States)

    Gu, Zhenyan; Lei, Wu; Shi, Wenyan; Hao, Qingli; Si, Weimeng; Xia, Xifeng; Wang, Fengxiang

    2014-11-01

    The interaction between 9-fluorenylmethyl chloroformate (FMOC-Cl) and Fe3+ and Cu2+ ions was investigated using fluorescence, UV/Vis absorption spectroscopies and theoretical calculation. The optical property of FMOC-Cl was studied in detail in absence and presence of various transition metal ions with particular affinity to Fe3+ and Cu2+ ions. With the fluorescence characteristic band centered at 307 and 315 nm for FMOC-Cl, the introduction of Fe3+ or Cu2+ ions leads to the fluorescence quenching of FMOC-Cl with different shift and intensities of two fluorescent bands. It allows us to differentiate between FMOC-Cl and Fe3+ and Cu2+ ions interaction behavior. The study on fluorescent kinetics confirms that the fluorescence quenching of FMOC-Cl with Fe3+ and Cu2+ ions is based on the formation of non-fluorescent material, that is, static quenching. Further analyses of bond lengths, Mulliken atomic charges and the frontier orbital compositions for FMOC-Cl and its complexes with Fe3+ and Cu2+ ions were carried out. The theoretical calculations prove the fluorescence quenching originates from the formation of coordination bonds between the oxygen atom of the carbonyl group of FMOC-Cl and Fe3+ and Cu2+ ions. The commercially available FMOC-Cl can be used as excellent fluorescent probe toward Fe3+ and Cu2+ ions with high sensitivity.

  19. Negative magnetoresistance in an antiferromagnetic metal β″-(EDO-TTFVODS) 2FeBr 4(DCE) 0.5

    Science.gov (United States)

    Weng, Yufeng; Yoshino, Harukazu; Fujiwara, Hideki; Sugimoto, Toyonari; Murata, Keizo

    2008-12-01

    An organic conductor β″-(EDO-TTFVODS) 2FeBr 4(DCE) 0.5, where EDO-TTFVODS is ethylenedioxytetrathiafulvalenoquinone-1,3-diselenolemethide and DCE is 1,2-dichloroethane, has been synthesized and is expected to have a strong π-d interaction. It was found that the material is metallic down to about 4 K and shows a rather slight upturn of electrical resistivity ρ below this temperature. Temperature dependence of ρ in the slight upturn region is proportional to log T and weak negative magnetoresistance (-1.7%, 2 T) at 1.4 K also appears. Besides π-d interaction screened by conducting electrons in this material, weak localization and Kondo effect are also possible to explain this negative magnetoresistance. Oscillatory behavior probably due to a quasi-two-dimensional (Q2D) Fermi surface was observed in the field-orientation dependence, and kF‖ b' was estimated to be 0.19 Å -1.

  20. Anisotropic Field Dependence of the Superconducting Transition in the Magnetic Molecular Superconductor κ-(BETS)2FeBr4

    Science.gov (United States)

    Fukuoka, Shuhei; Yamashita, Satoshi; Nakazawa, Yasuhiro; Yamamoto, Takashi; Fujiwara, Hideki

    2017-01-01

    Angle-resolved heat capacity measurements of a π-d interacting system of κ-(BETS)2FeBr4 [BETS = bis(ethylenedithio)tetraselenafulvalene] with in-plane magnetic fields are performed. We observed a thermal anomaly in association with the superconducting transition of the π electrons in the π-d compound for the first time. By pursuing a systematic change in the thermal anomaly, we found that the thermodynamic feature of the superconducting state shows large anisotropy against in-plane magnetic fields. When the field is applied parallel to the c-axis, the thermal anomaly remains up to 2.6 T with a distinct peak structure. On the other hand, it is suppressed in synchrony with the decrease of the antiferromagnetic transition temperature, when the field is applied parallel to the a-axis. Our thermodynamic results indicate that the effect of the π-d interaction appears even when the π electrons are itinerant and that the anisotropic field-direction dependence of the superconducting transition originates from the correlation between superconductivity and magnetism.

  1. Synthesis and Structure of a New Copper(II)Complex Cu(C13H9N3O2Br)2·H2O

    Institute of Scientific and Technical Information of China (English)

    张修堂; 詹晓平; 吴鼎铭; 杨文斌; 卢灿忠

    2002-01-01

    The new copper(II) complex Cu(C13H9N3O2Br)2@H2O (N-(2-hydroxy-5-bromo- benzoyl)-N?-(picolinylidene)hydrazine is abbreviated as HL ) was obtained from the refluxing solution of Cu(CH3COO)2H2O and HL in the ethanol-N, N-dimethylformamide mix solvent. Crystal data: triclinic, space group P ī, a = 10.8620(3), b = 11.7453 (3), c = 12.4417(2) ?, α = 62.255(0), β = 79.097(2), γ = 86.764(2)°, V = 1378.52(6) ?3, Z = 2, Mr = 719.835, Dc = 1.734 g/cm3, F(000) = 714, μ(MoKα) = 3.739 mm-1, T = 293(2) K, final R = 0.0594 and wR = 0.1416 for 2943 observed reflections with I > 2.0σ(I). The structure of Cu(C13H9N3O2Br)2@H2O has been determined by X-ray analysis and revealed that two L-1 ligands coordinate to the copper(Ⅱ) ion through two oxygen and two nitrogen atoms from the hydrazine groups and two pyridine nitrogen atoms to form an elongated and distorted square-bipyramidal environment for Cu(Ⅱ). The complex is also characterized by 1H NMR spectroscopies

  2. First-Principles Study of the Role of Cu in Improving the Coercivity of Nd-Fe-B Permanent Magnets

    Science.gov (United States)

    Tatetsu, Y.; Tsuneyuki, S.; Gohda, Y.

    2016-12-01

    We study the magnetic and electronic properties of Cu-doped Nd2 Fe14 B /NdOx systems with first-principles calculations in order to understand the roles of Cu in improving the coercivity of Nd-Fe-B permanent magnets. By analyzing the formation energies of several model systems, we find that Cu prefers to be at the interface. We conclude that the Cu addition to Nd-Fe-B magnets is a practical way of not only increasing the anisotropy of Nd atoms at the interface but also of lessening the magnetic coupling between the Nd and Fe atoms. Particularly, substituting Fe at the interface of the main phase with Cu works effectively in terms of improving the magnetic anisotropy in Nd atoms. This may explain the coercivity improvements reported recently.

  3. Comparative investigation of CuFe2O4 nano and microstructures for structural, morphological, optical and magnetic properties

    Science.gov (United States)

    Raja, G.; Gopinath, S.; Raj, R. Azhagu; Shukla, Arun K.; Alhoshan, Mansour S.; Sivakumar, K.

    2016-09-01

    CuFe2O4 nanocrystals were synthesized by the sol-gel method (SGM) and microwave method (MM) by using sucrose as a fuel. The structural, morphological, optical and magnetic properties of the products were determined and characterized in detail by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). The XRD results confirmed the formation of cubic phase CuFe2O4. The formation of CuFe2O4 nano and microstructures were confirmed by HR-SEM. Photoluminescence emissions were determined by PL spectra, respectively. The relatively high saturation magnetization (78.22 emu/g) of CuFe2O4-MM shows that it is ferromagnetic and low saturation magnetization (35.98 emu/g) of CuFe2O4O-SGM confirms the super paramagnetic behavior.

  4. Anisotropic photoelectric film assembled from mesoporous silica (MS)@CuO@FeS2 composite microspheres for improving photoelectric conversion.

    Science.gov (United States)

    Zong, Jie; Zhu, Yihua; Shen, Jianhua; Yang, Xiaoling; Li, Chunzhong

    2013-07-15

    We report a novel strategy for the fabrication of mesoporous silica (MS)@CuO@FeS2 composite microsphere-based anisotropic films that combine the advantages of the CuO and FeS2 materials to improve photoelectric conversion. This was achieved by aligning MS@CuO@FeS2 composite microspheres in a cross-linked gel under a homogeneous magnetic field. The MS@CuO@FeS2 composite microspheres, which were synthesized by a simple layer-by-layer (LbL) self-assembly technique together with a solvothermal method, can absorb a wide range of light and exhibit ferromagnetic properties. In addition, the resulting MS@CuO@FeS2 composite microsphere-based anisotropic film shows photoelectric anisotropy. Such systems are promising for improving the performance of solar cells.

  5. Improvement of Thermal Stability of Nd-Tb-Fe-Co-B Sintered Magnets by Additions of Pr, Ho, Al, and Cu

    Directory of Open Access Journals (Sweden)

    A. A. Lukin

    2012-01-01

    Full Text Available The present work investigates the influence of Pr, Al, Cu, B and Ho which were introduced into the Co-containing sintered magnets of Nd-Dy-Tb-Fe-Co-B type on the magnetic parameters (α, Hci, Br, BHmax⁡. The effect of heat treatment parameters on magnetic properties was also studied. It was revealed that the essential alloying of NdFeB magnets by such elements as Dy, Tb, Ho, Co as well as by boron-forming elements, for example, by titanium, may lead to reducing of F-phase quantity, and, as a consequence, to decreasing of magnetic parameters. It was also shown that additional doping of such alloys by Pr, B, Al and Cu leads to a significant increase of the quantity of F-phase in magnets as well as solubility of the Dy, Tb, Ho and Co in it. This promotes the increase of magnetic parameters. It was possible to attain the following properties for the magnets (Nd0,15Pr0,35Tb0,25Ho0,2515(Fe0,71Co0,29bal ⋅ Al0,9Cu0,1B8,5 (at. % after optimal thermal treatment {1175 K (3,6–7,2 ks with slow (12–16 ks cooling to 675 K and subsequently remaining at T=775 K for 3,6 ks—hardening}: Br=0,88 T, Hci=1760 kA/m, BHmax⁡=144 kJ/m3, α<|0,01|%/K in the temperature interval 223–323 K.

  6. Effects of ultrasonic field in pulse electrodeposition of NiFe film on Cu substrate

    Energy Technology Data Exchange (ETDEWEB)

    Balachandran, R. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Yow, H.K. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia)], E-mail: hkyow@mmu.edu.my; Ong, B.H. [Faculty of Engineering, Multimedia University, Cyberjaya Campus, 63100, Cyberjaya (Malaysia); Manickam, R. [Electronics Faculty, Tyndale Education Group Pte Ltd., 188942 (Singapore); Saaminathan, V. [School of Material Science and Engineering, Nanyang Technological University, 639798 (Singapore); Tan, K.B. [Department of Chemistry, Universiti Putra Malaysia, Serdang, 43400 (Malaysia)

    2009-07-29

    NiFe film was pulse electrodeposited on conductive Cu substrate under galvanostatic mode in the presence of an ultrasonic field. The NiFe film electrodeposited was subjected to structural and surface analyses by X-ray diffraction, energy dispersive X-ray spectroscopy, surface profiling and scanning electron microscopy, respectively. The results show that the ultrasonic field has significantly improved the surface roughness, reduced the spherical grain size in the range from 490-575 nm to 90-150 nm, and increased the Ni content from 76.08% to 79.74% in the NiFe film electrodeposited.

  7. Effects of Si/Al Ratio on Cu/SSZ-13 NH3-SCR Catalysts: Implications for the active Cu species and the Roles of Brønsted Acidity

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Washton, Nancy M.; Wang, Yilin; Kollar, Marton; Szanyi, Janos; Peden, Charles HF

    2015-09-03

    Cu/SSZ-13 catalysts with three Si/Al ratios of 6, 12 and 35 were synthesized with Cu incorporation via solution ion exchange. The implications of varying Si/Al ratios on the nature of the multiple Cu species that can be present in the SSZ-13 zeolite are a major focus of this work, as highlighted by the results of a variety of catalyst characterization and reaction kinetics measurements. Specifically, catalysts were characterized with surface area/pore volume measurements, temperature programmed reduction by H2 (H2-TPR), NH3 temperature programmed desorption (NH3-TPD), and DRIFTS and solid-state nuclear magnetic resonance (NMR) spectroscopies. Catalytic properties were examined using NO oxidation, ammonia oxidation, and standard ammonia selective catalytic reduction (NH3-SCR) reactions on selected catalysts under differential conditions. Besides indicating possible variably active multiple Cu species for these reactions, the measurements are also used to untangle some of the complexities caused by the interplay between redox of Cu ion centers and Brønsted acidity. All three reactions appear to follow a redox reaction mechanism, yet the roles of Brønsted acidity are quite different. For NO oxidation, increasing Si/Al ratio lowers Cu redox barriers, thus enhancing reaction rates. Brønsted acidity appears to play essentially no role for this reaction. For standard NH3-SCR, residual Brønsted acidity plays a significant beneficial role at both low- and high-temperature regimes. For NH3 oxidation, no clear trend is observed suggesting both Cu ion center redox and Brønsted acidity play important and perhaps competing roles. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. The research described in this paper was performed in the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the DOE’s Office of

  8. Study of the C-14-contamination potential of C-impurities in CuO and Fe

    NARCIS (Netherlands)

    Vandeputte, K; Moens, L; Dams, R; van der Plicht, Johannes

    1998-01-01

    The carbon concentration in CuO and iron was determined by isolating C. The values were in agreement with results reported in other studies. Contaminating carbon from CuO and Fe was transformed to AMS targets and measured for C-14. C-traces in CuO were shown to be the major contribution to the C-14

  9. Photocatalytic performances and activities of Ag-doped CuFe{sub 2}O{sub 4} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhengru, E-mail: zhengruzhu@gmail.com [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China); State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Xinyong; Zhao, Qidong [State Key Laboratory of Fine Chemical, Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China); Li, Yonghua; Sun, Caizhi; Cao, Yongqiang [Research Center of Hydrology and Water Source, School of Urban and Environment, Liaoning Normal University, Dalian, 116029 (China)

    2013-08-01

    Graphical abstract: - Highlights: • CuFe{sub 2}O{sub 4} nanocrystals were synthesized by a co-precipitation method. • Ag/CuFe{sub 2}O{sub 4} catalyst was prepared by the wetness impregnation strategy. • The structural properties of Ag/CuFe{sub 2}O{sub 4} were investigated by XRD, TEM, DRS, and XPS techniques. • Ag/CuFe{sub 2}O{sub 4} has higher photocatalytic activity. - Abstract: In this work, CuFe{sub 2}O{sub 4} nanoparticles were synthesized by a chemical co-precipitation route. The Ag/CuFe{sub 2}O{sub 4} catalyst was prepared based on the CuFe{sub 2}O{sub 4} nanoparticles by the incipient wetness impregnation strategy, which showed excellent photoelectric property and catalytic activity. The structural properties of these samples were systematically investigated by X-ray powder diffraction (XRD), transmission electronic microscopy (TEM), UV–vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) techniques. The photo-induced charge separation in the samples was demonstrated by surface photovoltage (SPV) measurement. The photocatalytic degradation of 4-CP by the Ag/CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4} samples were comparatively studied under xenon lamp irradiation. The results indicate that the Ag/CuFe{sub 2}O{sub 4} sample exhibited the higher efficiency for the degradation of 4-CP.

  10. Unusual Solidification Behavior of the Suction-Cast Cu-Zr-Al-Y Alloy Doped with Fe

    Science.gov (United States)

    Kozieł, Tomasz; Cios, Grzegorz; Latuch, Jerzy; Pajor, Krzysztof; Bała, Piotr

    2017-04-01

    The effect of iron addition on the microstructure of the Cu-Zr-Al-Y glass-forming alloy was studied. Despite a high superficial cooling rate, small Fe additions (1.5 and 3 pct) induced formation of crystalline CuZr and AlCu2Zr phases on the outer layers of suction-cast rods. As the melt composition near the solid/liquid interface was depleted in Fe, the remaining melt vitrified at a relatively low cooling rate.

  11. Preparation and characterization of ultrafine Fe-Cu-based catalysts for CO hydrogenation

    Institute of Scientific and Technical Information of China (English)

    Yunlai Su; Yingli Wang; Zhongmin Liu

    2008-01-01

    The ultrafine particles of a new style Fe-Cu-based catalysts for CO hydrogenation were prepared by impregnating the organic sol of Fe(OH)3 and Cu(OH)2 onto the activated Al2O3, in which the organic sol of Fe(OH)3 and Cu(OH)2 were pre-pared in the microemulsion of dodecylbenzenesulfonic acid sodium(S)/n-butanol(A)/toluene(O)/water with V(A)/V(O) = 0.25 and W(A)/W(S)=1.50. This catalyst was characterized by particle size analysis, XRD and TG. The results of particle size analysis showed that Fe(OH)3 particles with a mean size of 17.1 nm and Cu(OH)2 particles with an average size of 6.65 μm were obtained. TG analysis and XRD patterns suggested that 673 K is the optimal calcination temperature. CO hydrogenation produced C+2 OH with a high selectivity above 58 wt% by using the ultrafine particles as catalyst, and the total alcohol yield of 0.250 g·ml-1·h-1 was obtained when the contents of Al2O3 and K were 88.61 wt% and 1.60 wt%, respectively.

  12. The Reaction Mechanism and Rate Constants in the Radiolysis of Fe2+-Cu2+ Solutions

    DEFF Research Database (Denmark)

    Bjergbakke, Erling; Sehested, Knud; Rasmussen, O. Lang

    1976-01-01

    Pulse radiolysis and gamma radiolysis have been used to study the reaction mechanism in the radiolysis of aqueous solutions of Fe2+ and Cu2+. A reaction scheme has been developed and confirmed by computation of the corresponding complete set of differential equations. The rate constants for some...

  13. MOKE spectroscopy of FePtCu thin films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Fronk, Michael; Smykalla, Lars; Brombacher, Christoph; Schubert, Christian; Albrecht, Manfred; Salvan, Georgeta [Chemnitz University of Technology (Germany)

    2010-07-01

    Since the uniaxial magnetic anisotropy of FePt in its chemically ordered L1{sub 0} phase can reach 10 MJ/m{sup 3} FePt is considered to be a promising material for future magnetic storage devices. In this work Fe{sub 52}Pt{sub 48}(5 nm-x)/Cu(x) bilayers have been sputter deposited at room temperature onto thermally oxidized Si wafers and afterwards annealed to various temperatures between 450 C and 800 C under N{sub 2} atmosphere using a commercial rapid thermal annealing (RTA) setup. The RTA procedure leads to the formation of a ternary FePtCu alloy with pronounced perpendicular magnetic anisotropy. The dependence of both the coercivity and remanence extracted from polar MOKE hysteresis loops at 1.96 eV on the annealing temperature will be discussed with respect to the initial Cu thicknesses of 0.5 nm and 0.9 nm. In addition, MOKE-spectroscopy in the energy range between 1.7 eV and 5.5 eV was performed and a clear dependence on the initial Cu thickness and the annealing temperature is found. In some of the spectra the main spectral feature at around 2 eV exhibits a fine structure, which could be caused by the coexistence of the two crystalline phases and/or by the presence of defect sites.

  14. Comparative study on the reactivity of Fe/Cu bimetallic particles and zero valent iron (ZVI) under different conditions of N2, air or without aeration.

    Science.gov (United States)

    Xiong, Zhaokun; Lai, Bo; Yang, Ping; Zhou, Yuexi; Wang, Juling; Fang, Shuping

    2015-10-30

    In order to further compare the degradation capacity of Fe(0) and Fe/Cu bimetallic system under different aeration conditions, the mineralization of PNP under different aeration conditions has been investigated thoroughly. The results show that the removal of PNP by Fe(0) or Fe/Cu system followed the pseudo-first-order reaction kinetics. Under the optimal conditions, the COD removal efficiencies obtained through Fe(0) or Fe/Cu system under different aeration conditions followed the trend that Fe/Cu (air)>Fe/Cu (N2: 0-30 min, air: 30-120 min)>control-Fe (air)>Fe/Cu (without aeration)>Fe/Cu (N2)>control-Fe (N2). It revealed that dissolved oxygen (DO) could improve the mineralization of PNP, and Cu could enhance the reactivity of Fe(0). In addition, the degradation of PNP was further analyzed by using UV-vis, FTIR and GC/MS, and the results suggest that Fe/Cu bimetallic system with air aeration could completely break the benzene ring and NO2 structure of PNP and could generate the nontoxic and biodegradable intermediate products. Meanwhile, most of these intermediate products were further mineralized into CO2 and H2O, which brought about a high COD removal efficiency (83.8%). Therefore, Fe/Cu bimetallic system with air aeration would be a promising process for toxic refractory industry wastewater.

  15. Cu substitution effects on the local magnetic properties of Ba(Fe(1-x)Cu(x))(2)As(2): a site-selective (75)As and (63)Cu NMR study.

    Science.gov (United States)

    Takeda, Hikaru; Imai, Takashi; Tachibana, Makoto; Gaudet, Jonathan; Gaulin, Bruce D; Saparov, Bayrammurad I; Sefat, Athena S

    2014-09-12

    We take advantage of the site-selective nature of the ^{75}As and ^{63}Cu NMR techniques to probe the Cu substitution effects on the local magnetic properties of the FeAs planes in Ba(Fe_{1-x}Cu_{x})_{2}As_{2}. We show that the suppression of antiferromagnetic Fe spin fluctuations induced by Cu substitution is weaker than a naive expectation based on a simple rigid band picture, in which each Cu atom would donate three electrons to the FeAs planes. Comparison between ^{63}Cu and ^{75}As NMR data indicates that spin fluctuations are suppressed at the Cu and their neighboring Fe sites in the tetragonal phase, suggesting the strongly local nature of the Cu substitution effects. We attribute the absence of a large superconducting dome in the phase diagram of Ba(Fe_{1-x}Cu_{x})_{2}As_{2} to the emergence of a nearly magnetically ordered FeAs plane under the presence of orthorhombic distortion.

  16. Multifractal analysis of the strength of Fe-Cu paragenetic relationships in eastern Tianshan, China

    Science.gov (United States)

    Zhao, Jie; Wang, Wenlei; Cheng, Qiuming

    2016-04-01

    Paragenetic association of elements is a natural and important geological phenomenon reflecting the geochemical behavior of elements during various geo-processes. Because of intrinsic characteristics, different elements of paragenetic association may also be generated. As a result, the respective material sources could be shifted from the original locations, and the strength of paragenetic association of elements could be declined. Therefore, study of paragenetic association of elements can help in locating material source, characterizing migration form, and indicating precipitation conditions. Resulted from complicated and cascade geo-processes, the strength of paragenetic relationship between elements presents variations in space. To examine influences of the strength of paragenetic association of elements on polymetallic mineralization, the current research proposes a data processing procedure that includes non-linear regression and multifractal analysis of the resulting regression coefficients. This procedure is currently tested in the eastern Tianshan mineral district, China, and encouraging results are being derived. In this research, geographically weighted regression (GWR), which is a non-linear statistical method, is used to examine the relationship between Fe and Cu concentrations in eastern Tianshan mineral district, China. This local regression method allows calculation of coefficients for Fe and Cu concentrations at every individual location. Therefore, the variation of the strength of Fe-Cu paragenetic association across the study area can be derived. Furthermore, a multifractal method, spectrum-area (S-A) analysis is applied to the regression coefficient map in order to delineate locations strong associated with Fe-Cu mineralization. Anomalies indicating very strong paragenetic association are separated from background. In addition, noise indicating locations with strong paragenetic relationships but that are not suitable for Fe-Cu mineralization are

  17. EFFECT OF COPPER ON PASSIVITY AND CORROSION BEHAVIOR OF FE-XC-5CU ALLOY

    Directory of Open Access Journals (Sweden)

    M. Ferhat

    2014-06-01

    Full Text Available The correlation between corrosion behavior rate of annealed Fe-xC-5Cu alloys and their microstructure and phase composition is presented. The metallurgical analyses, including, X-Ray diffraction (XRD, the scanning electron microscopy (SEM with energy dispersive analysis (EDX, and induction hardening characterization are conducted to study the Fe-C-Cu alloys. Corrosion parameters in H2SO4 1N solution have been established by carrying out electrochemical studies such as potentiodynamic (Tafel polarization and linear polarization, LP and electrochemical impedance spectroscopy (EIS. The coupled effect copper/microstructure is discussed. Alloying Cu showed a beneficial effect on hypoeutectoid steel and harmful effect on hypereutectoid steel. The improved corrosion resistance is related to cementite morphology and by a copper dissolution/re-deposition process.

  18. EFFECT OF COPPER ON PASSIVITY AND CORROSION BEHAVIOR OF FE-XC-5CU ALLOY

    Directory of Open Access Journals (Sweden)

    M. Ferhat

    2015-07-01

    Full Text Available The correlation between corrosion behavior rate of annealed Fe-xC-5Cu alloys and their microstructure and phase composition is presented. The metallurgical analyses, including, X-Ray diffraction (XRD, the scanning electron microscopy (SEM with energy dispersive analysis (EDX, and induction hardening characterization are conducted to study the Fe-C-Cu alloys. Corrosion parameters in H2SO4 1N solution have been established by carrying out electrochemical studies such as potentiodynamic (Tafel polarization and linear polarization, LP and electrochemical impedance spectroscopy (EIS. The coupled effect copper/microstructure is discussed. Alloying Cu showed a beneficial effect on hypoeutectoid steel and harmful effect on hypereutectoid steel. The improved corrosion resistance is related to cementite morphology and by a copper dissolution/re-deposition process.

  19. Effect of Fe and Cu on Electrochemical Characteristics of Low-Co AB5 Type Alloys

    Institute of Scientific and Technical Information of China (English)

    Zhu Xilin; Zhou Yu; Chong Fayao; Li Xiaochun; Pan Weilin

    2004-01-01

    In order to further reduce the cost of AB5 type rare earth-based hydrogen storage alloy, a low-Co AB5 type hydrogen storage alloy were by substituting Co with Cu and Fe.The characteristics of these alloys have been investigated by means of XRD, PCT, and measurement of electrochemical capacity and cycle life.The test results show that the effect of these two kinds of substituting elements on discharge capacity is CuFe, and the cycle life is on the contrary.Both of them have no distinct influence on activity speed, but activity speed increases with the decrease of Co.By the order way, the high discharge rate characteristics rise with the addition of Cu and decreasing of Co.

  20. Effect of Ag addition on the as-cast microstructure of Cu-8 wt.% Fe in situ composites

    Energy Technology Data Exchange (ETDEWEB)

    Xie Zhixiong [State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University, 800 Dong Chuan Road, Shanghai 200240 (China); Gao Haiyan, E-mail: gaohaiyan@sjtu.edu.c [State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University, 800 Dong Chuan Road, Shanghai 200240 (China); Lu Qin; Wang Jun; Sun Baode [State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University, 800 Dong Chuan Road, Shanghai 200240 (China)

    2010-10-22

    Research highlights: {yields} Ag addition refines the primary Fe dendrites. {yields} Ag inhibits the solubility of Fe in Cu matrix at high temperature. {yields} Refinement mechanism is explained by wetting properties between Cu-Ag and {gamma}-Fe. - Abstract: Ternary copper-based composites consisting of Cu, 8 wt.% Fe and 0.1-6 wt.% Ag were prepared by inductive melting and casting. The effect of Ag addition on the as-cast microstructure was investigated using optical microscopy (OM) and scanning electron microscopy (SEM). The results show that the primary Fe dendrites in the as-cast microstructure are refined significantly with the presence of Ag. Contact angle between Cu-Ag alloy and {gamma}-Fe was measured using sessile drop technique to investigate the refinement mechanism of the primary Fe dendrites. In addition, the effect of Ag addition on the dissolution of Fe atoms in the Cu matrix at high temperature was investigated by means of energy dispersive X-ray spectroscopy (EDS). The results show that the presence of Ag inhibits the solubility of Fe in the Cu matrix at high temperature.

  1. Enhanced magnetocrystalline anisotropy of Fe30Co70 nanowires by Cu additives and annealing

    Science.gov (United States)

    Palmero, Ester M.; Salikhov, Ruslan; Wiedwald, Ulf; Bran, Cristina; Spasova, Marina; Vázquez, Manuel; Farle, Michael

    2016-09-01

    The use of 3d transition metal-based magnetic nanowires (NWs) for permanent magnet applications requires large magnetocrystalline anisotropy energy (MAE), which in combination with the NWs’ magnetic shape anisotropy yields magnetic hardening and an enhancement of the magnetic energy product. Here, we report on the significant increase in MAE by 125 kJ m-3 in Fe30Co70 NWs with diameters of 20-150 nm embedded in anodic aluminum oxide templates by adding 5 at.% Cu and subsequent annealing at 900 K. Ferromagnetic resonance (FMR) reveals that this enhancement of MAE is twice as large as the enhancement of MAE in annealed, but undoped NWs. X-ray diffraction (XRD) analysis suggests that upon annealing the immiscible Cu in FeCo NWs causes a crystal reorientation with respect to the NW axis with a considerable distortion of the bcc FeCo lattice. This strain is most likely the origin of the strongly enhanced MAE.

  2. Ferromagnetism of Fe{sub 86}Mn{sub 14-y}Cu{sub y} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Franca, F. [DF-UDESC, Joinville, CEP 89223-100, SC (Brazil); Paduani, C. [DF-UFSC, Florianopolis, CEP 88040-900, SC (Brazil)]. E-mail: paduani@fisica.ufsc.br; Krause, J.C. [DCET-URI, Santo Angelo, CEP 98802-470, RS (Brazil); Ardisson, J.D. [CDTN, Belo Horizonte, CEP 30123-970, MG (Brazil); Yoshida, M.I. [DQ-ICEX-UFMG, Belo Horizonte, CEP 31270-901, MG (Brazil); Schaf, J. [IF-UFRGS, Porto Alegre, CEP 91501-970, RS (Brazil)

    2007-01-01

    The magnetic properties of disordered Fe{sub 86}Mn{sub 14-y}Cu{sub y} alloys were investigated with several experimental techniques. The results of X-ray diffraction showed that these alloys are single phase with the A2 (BCC) structure. These are ferromagnetic alloys at room temperature, and the Curie temperature decreases with the increase of the Cu content. An abrupt loss of magnetization was observed below T{sub C} at a temperature which increases with the reduction of the Mn content in the alloys. The addition of manganese enhances the solubility of copper in iron matrix and retains the BCC structure in iron-rich alloys. The behavior of the magnetization with temperature and its composition dependence indicate that an antiferromagnetic coupling is expected between the Fe and Mn atoms. The magnetic moments of both Fe and Mn atoms are expected to vary strongly with composition in these alloys.

  3. More Cu, more problems: Decreased CO2 conversion ability by Cu-doped La0.75Sr0.25FeO3 perovskite oxides

    Science.gov (United States)

    Daza, Yolanda A.; Maiti, Debtanu; Hare, Bryan J.; Bhethanabotla, Venkat R.; Kuhn, John N.

    2016-06-01

    The effect of Cu doping on the conversion of CO2 to CO was investigated on H2-reduced La0.75Sr0.25FeO3 perovskite oxides. Six La0.75Sr0.25Fe1 -YCuYO3 perovskites, labeled Cu100*Y (with Y = 0, 0.10, 0.25, 0.50, 0.75, and 1) were synthesized and characterized through X-ray diffraction (XRD), temperature-programmed oxygen vacancy formation, and temperature-programmed reduction (TPR). The incorporation of Cu facilitates the formation of oxygen vacancies at lower temperatures but also increased the instability of the perovskite. DFT simulations suggested that the Cu10 sample is favored to produce oxygen vacancies compared to Cu0 and Cu25 samples, which was consistent with experimental oxygen vacancy formation results. For the Cu0, Cu10, and Cu25 samples, temperature-programmed CO2 conversion (TPO-CO2) after isothermal H2-reduction at 450 °C and post-reduction XRD were performed to evaluate the ability of the materials to convert CO2 at low temperatures and to identify the crystalline phases active in the reaction. The peak conversion of CO2 to CO was achieved 30 °C lower on the Cu10 sample versus the Cu0, but less CO was produced, due to a decreased re-oxidation activity of the Cu-doped samples. CO production was inhibited in the Cu25 sample, likely due to a combined effect of poor CO2 dissociative chemisorption energies on metallic Cu and increased thermodynamic stability of the oxygen vacant perovskites. Control experiments (Cu deposited onto La0.75Sr0.25FeO3) indicated the stability of the copper-containing perovskite oxides phases was the primary limiting factor preventing CO formation from CO2.

  4. Anomalous grain growth in nanocrystalline Fe73.5Cu1Nb3Su13.5B9 alloys

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    1997-01-01

    The grain growth of the FeSi phase during the crystallization process of the amorphous Fe73.5Cu1Nb3Si13.5B9 alloy was studied using transmission electron microscopy and x-ray diffractometry. An anomalous grain growth behaviour of the FeSi phase in the samples annealed in temperature range from 74...

  5. Coagulation-flocculation as pre-treatment for micro-scale Fe/Cu/O3 process (CF-mFe/Cu/O3) treatment of the coating wastewater from automobile manufacturing.

    Science.gov (United States)

    Xiong, Zhaokun; Cao, Jinyan; Yang, Dan; Lai, Bo; Yang, Ping

    2017-01-01

    A coagulation-flocculation as pre-treatment combined with mFe/Cu/O3 (CF-mFe/Cu/O3) process was developed to degrade the pollutants in automobile coating wastewater (ACW). In coagulation-flocculation (CF) process, high turbidity removal efficiency (97.1%) and low COD removal efficiency (10.5%) were obtained under the optimal conditions using Al2(SO4)3·18H2O and CaO. The effluent of CF process (ECF) was further disposed by mFe/Cu/O3 process, and its key operating parameters were optimized by batch experiments. Optimally, COD removal efficiency of ECF obtained by the mFe/Cu/O3 process (i.e., 87.6% after 30 min treatment) was much higher than those of mFe/Cu alone (8.3%), ozone alone (46.6%), and mFe/Cu/air (6.1%), which confirms the superiority of the mFe/Cu/O3 process. In addition, the analysis results of UV-vis, excitation-emission matrix (EEM) fluorescence spectra and GC/MS further confirm that the phenol pollutants of ECF had been effectively decomposed or transformed after CF-mFe/Cu/O3 process treatment. Meanwhile, B/C ratio of ACW increased from 0.19 to 0.56, which suggests the biodegradability was improved significantly. Finally, the operating cost of CF-mFe/Cu/O3 process was about 1.83 USD t(-1) for ACW treatment. Therefore, the combined process is a promising treatment technology for the coating wastewater from automobile manufacturing.

  6. Removal of Cd2+ and Cu2+ ions from aqueous solution by using Fe-Fe3O4/graphene oxide as a novel and efficient adsorbent

    Science.gov (United States)

    Le, Giang H.; Ha, Anh Q.; Nguyen, Quang K.; Nguyen, Kien T.; Dang, Phuong T.; Tran, Hoa T. K.; Vu, Loi D.; Nguyen, Tuyen V.; Lee, Gun D.; Vu, Tuan A.

    2016-10-01

    The nano Fe-Fe3O4/graphene oxide (GO) was successfully synthesized by the precipitation method and followed by chemical reduction using FeCl3 as iron sources and NaBH4 as reducing agent. The products were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), BET, x-ray photoelectron spectroscopy (XPS) and VMS. From the obtained XRD and XPS results, it revealed the formation of both Fe and Fe3O4 nano particles on GO surface. TEM images showed that both Fe3O4/GO and Fe-Fe3O4/GO had small particle size of 10-20 nm and uniform size distribution. Fe3O4/GO and Fe-Fe3O4/GO were used as adsorbents for removal of Cd2+ and Cu2+ ions from aqueous solution. Maximum adsorption capacity (Q max) of Fe-Fe3O4/GO for Cu2+ and Cd2+ are 90.0 mg g-1 and 108.6 mg g-1, respectively. These values are much higher as compared to those of Fe3O4/GO as well as those reported in the literature. Additionally, this novel adsorbent can be reused by washing with diluted Hcl solution and easily recovered by applying the magnetic field. The Cd2+ adsorption isotherm fits better for the Langmuir model that of the Freundlich model and it obeys the pseudo-second order kinetic equation.

  7. A Novel Ternary CoFe2O4/CuO/CoFe2O4 as a Giant Magnetoresistance Sensor

    Directory of Open Access Journals (Sweden)

    Ramli

    2016-12-01

    Full Text Available This paper reports the results of a study relating to the synthesis of a novel ternary CoFe2O4/CuO/CoFe2O4 thin film as a giant magnetoresistance (GMR sensor. The CoFe2O4/CuO/CoFe2O4 thin film was prepared onto silicon substrate via DC magnetron sputtering with the targets facing each other. X-ray diffraction was used to determine the structure of the thin film and a 4-point method was used to measure the MR ratio. The GMR ratio is highly dependent on the ferrimagnetic (CoFe2O4 and nonmagnetic (CuO layer thickness. The maximum GMR ratio at room temperature obtained in the CoFe2O4/CuO/CoFe2O4 thin film was 70% when the CoFe2O4 and the CuO layer had a thickness of 62.5 nm and 14.4 nm respectively.

  8. Antifungal activity of magnetically separable Fe3O4/ZnO/AgBr nanocomposites prepared by a facile microwave-assisted method

    Institute of Scientific and Technical Information of China (English)

    Abolghasem Hoseinzadeh; Aziz Habibi-Yangjeh; Mahdi Davari

    2016-01-01

    In the present work, magnetically separable Fe3O4/ZnO/AgBr nanocomposites with different weight ra-tios of Fe3O4 to ZnO/AgBr were prepared by a facile microwave-assisted method. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission elec-tron microscopy (TEM), energy dispersive analysis of X-rays (EDX), and vibrating sample magnetometery (VSM). Antifungal activity of the as-prepared samples was evaluated against Fusarium graminearum and Fusarium oxysporum as two phytopathogenic fungi. Among the nanocomposites, the sample with 1:8 weight ratio of Fe3O4 to ZnO/AgBr was selected as the best nanocomposite. This nanocomposite in-activates Fusarium graminearum and Fusarium oxysporum at 120 and 60 min, respectively. Moreover, it was observed that the microwave irradiation time has considerable influence on the antifungal activity and the sample prepared by irradiation for 10 min showed the best activity. Moreover, the nano-composite without any thermal treatment displayed the superior activity.

  9. Tween-80存在下5-Br-PADAP分光光度法测定饮用水中微量铁%Test of Trace Fe in Drinking-water in Tween-80 with 5-Br-PADAP Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    刘晓权; 范建成

    2003-01-01

    在PH=4.70的弱酸性介质中,Fe(Ⅲ)在非离子表面活性剂Tween-80存在下与5-Br-PADAP生成红色配合物,配合物最大吸收波长λmax位于600nm处,表观摩尔吸光系数ε6000为9.8×104L·mol-1.cm-1,Fe(Ⅲ)在0~14μg/25ml范围内符合比尔定律.本法用于饮用水样中微量铁的测定,结果满意.

  10. Measurement of interlayer spin diffusion in the organic conductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]X, X=Cl, Br

    Energy Technology Data Exchange (ETDEWEB)

    Antal, Agnes; Feher, Titusz [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary); Nafradi, Balint [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary); Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Gaal, Richard; Forro, Laszlo [Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Janossy, Andras, E-mail: atj@szfki.h [Institute of Physics, Budapest University of Technology and Economics, and Condensed Matter Research Group of the Hungarian Academy of Sciences, P.O.Box 91, H-1521 Budapest (Hungary)

    2010-06-01

    In organic conductors the overlap integral between layers is small, in-plane momentum scattering is rapid and transport perpendicular to the layers is expected to be blocked. We present a high frequency conduction electron spin resonance (CESR) study in the layered organic metals {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]X, X=Cl, Br, which verifies that the inter-layer spin hopping is effectively blocked. The method relies on resolving the CESR lines of adjacent layers in which the orientation of the g-factor tensors differs. We find that at ambient pressure and in the metallic phase the electron spin diffusion is two dimensional in both the X=Cl and Br compounds, i.e. electrons diffuse longer than the spin lifetime within a single molecular layer without inter-layer hopping. Application of pressure at 250 K increases rapidly the inter-layer hopping rate of spins.

  11. Development and characterization of the CU ground MAX-DOAS instrument: lowering RMS noise and first measurements of BrO, IO, and CHOCHO near Pensacola, FL

    Directory of Open Access Journals (Sweden)

    S. Coburn

    2011-01-01

    Full Text Available We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS instrument to retrieve bromine oxide (BrO, iodine oxide (IO, formaldehyde (HCHO, glyoxal (CHOCHO, nitrogen dioxide (NO2 and the oxygen dimer O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is directly proportional to the root mean square (RMS of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS values of ~6 × 10-6 without apparent limitations other than photon shot noise. <br>> Laboratory tests revealed two factors that, in practice, limit the RMS: (1 detector non-linearity noise, RMSNLin, and (2 temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (~10−3 yet – unless actively controlled – is sufficiently large to create a RMSNLin limit of up to 1.4 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels/°C at 334 nm, and temperature variations of 0.1 °C can cause residual RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. <br>> The CU GMAX-DOAS was set up at a coastal site near Pensacola, FL, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL, with daytime average tropospheric vertical column densities, VCDs, of ~2 × 1013 molec cm−2, 8 × 1012 molec cm−2 and 4 × 1014 molec cm−2, respectively. HCHO and NO2 were also detected with typical MBL VCDs of 1

  12. The CU ground MAX-DOAS instrument: characterization of RMS noise limitations and first measurements near Pensacola, FL of BrO, IO, and CHOCHO

    Directory of Open Access Journals (Sweden)

    S. Coburn

    2011-11-01

    Full Text Available We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS instrument to retrieve bromine oxide (BrO, iodine oxide (IO, formaldehyde (HCHO, glyoxal (CHOCHO, nitrogen dioxide (NO2 and the oxygen dimer (O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is proportional to the root mean square (RMS of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS of ∼6 × 10−6 from solar stray light noise tests using high photon count spectra (compatible within a factor of two with photon shot noise. <br>> Laboratory tests revealed two critical instrument properties that, in practice, can limit the RMS: (1 detector non-linearity noise, RMSNLin, and (2 temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (∼10−2 yet – unless actively controlled – is sufficiently large to create RMSNLin of up to 2 × 10−4. The optical resolution is sensitive to temperature changes (0.03 detector pixels °C−1 at 334 nm, and temperature variations of 0.1°C can cause RMSFWHM of ~1 × 10−4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. With an integration time of 60 s the instrument can reach RMS noise of 3 × 10−5, and typical RMS in field measurements ranged from 6 × 10−5 to 1.4 × 10−4. <br>> The CU GMAX-DOAS was set up at a coastal site near Pensacola, Florida, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL, with daytime

  13. Solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO

    Directory of Open Access Journals (Sweden)

    Boyanov B.S.

    2005-01-01

    Full Text Available The solid state interactions in the systems CaO(CaCO3-Fe2O3 and CuFe2O4-CaO have been studied using X-ray diffraction analysis. The influence of the temperature on the ferrite formation process has been investigated in the range of 900-1200 oC and duration up to 360 min. It has been shown that a mixture of ferrites forms at 1000 oC and interaction of 240 min. The exchange reactions in the systems CuFe2O4-CaO and Cu0.5Zn0.5Fe2O4-CaO have been studied, too. It has been established that Ca2+ ions exchange Cu2+ and Zn2 partially and the solubility of copper and zinc in a 7 % sulfuric acid solution increases 10-15 times.

  14. Study of Cu-doping effects on magnetic properties of Fe-doped ZnO by first principle calculations

    Indian Academy of Sciences (India)

    A El Amiri; H Lassri; M Abid; E K Hlil

    2014-06-01

    Using ab initio calculations on Zn0.975–Fe0.025CuO ( = 0, 0.01, 0.02, 0.05), we study the variations of magnetic moments vs Cu concentration. The electronic structure is calculated by using the Korringa–Kohn–Rostoker (KKR) method combined with coherent potential approximation (CPA). We show that the total magnetic moment and magnetic moment of Fe increase on increasing Cu content. From the density of state (DOS) analysis, we show that Cu-induced impurity bands can assure, by two mechanisms, the enhancement of Fe magnetic moment in Zn0.975–Fe0.025CuO.

  15. Magnetic ordering of Fe atoms in oxygen-saturated and oxygen-reduced YBa sub 2 (Cu sub 1-x Fe sub x ) sub 3 O sub y

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, I.S.; Terziev, V.G.; Dmitrieva, T.V. (Inst. of Crystallography, Academy of Sciences, Moscow (Russia)); Balagurov, A.M. (Joint Inst. for Nuclear Research, Dubna (Russia)); Nasu, S. (Dept. of Material Physics, Osaka Univ. (Japan))

    1992-06-01

    The magnetic ordering of Fe atoms in the YBa{sub 2}(Cu{sub 1-x}Fe{sub x}){sub 3}O{sub y} system is studied in the superconducting (SC) and non-SC states by Moessbauer spectroscopy. In the SC samples a single magnetic ordering point T{sub m1} is observed for all Fe atoms: T{sub m1}=10 K and 16 K for x=0.05 and 0.10, respectively. In the non-SC state for x=0.05 the Cu(1) and Cu(2) sublattices are magnetically independent and two magnetic ordering points are found: T{sub m1}=20 K and T{sub m2}=405 K. For x=0.10 a strong magnetic coupling between the Cu(1) and Cu(2) sublattices leads to a single magnetic ordering temperature T{sub m2}=435 K. (orig.).

  16. Microstructures and Mechanical Properties of NiTiFeAlCu High-Entropy Alloys with Exceptional Nano-precipitates

    Science.gov (United States)

    Zhang, Yanqiu; Wang, Sibing; Jiang, Shuyong; Zhu, Xiaoming; Sun, Dong

    2016-10-01

    Three novel NiTiFeAlCu high-entropy alloys, which consist of nano-precipitates with face-centered cubic structure and matrix with body-centered cubic structure, were fabricated to investigate microstructures and mechanical properties. With the increase in Ni and Ti contents, the strength of NiTiFeAlCu alloy is enhanced, while the plasticity of NiTiFeAlCu alloy is lowered. Plenty of dislocations can be observed in the Ni32Ti32Fe12Al12Cu12 high-entropy alloy. The size of nano-precipitates decreases with the increase in Ni and Ti contents, while lattice distortion becomes more and more severe with the increase in Ni and Ti contents. The existence of nano-precipitates, dislocations and lattice distortion is responsible for the increase in the strength of NiTiFeAlCu alloy, but it has an adverse influence on the plasticity of NiTiFeAlCu alloy. Ni20Ti20Fe20Al20Cu20 alloy exhibits the substantial ability of plastic deformation and a characteristic of steady flow at 850 and 1000 °C. This phenomenon is attributed to a competition between the increase in the dislocation density induced by plastic strain and the decrease in the dislocation density due to the dynamic recrystallization.

  17. Simulation of magnetization behaviours of Sm(Co,Fe,Cu,Zr)z magnet with low Cu content

    Institute of Scientific and Technical Information of China (English)

    Chen Ren-Jie; Zhang Hong-Wei; Shen Bao-Gen; Yan A-Ru; Chen Li-Dong

    2009-01-01

    The effects of microstructure, cell orientation and temperature on magnetic properties and the coercivity mechanism in Sm(Co,Fe,Cu,Zr)z with low Cu content are studied by using the micromagnetic finite element method in this paper. The simulations of the demagnetization behaviours indicate that the pinning effect weakens gradually with the thickness of cell boundary decreasing and strengthens gradually with the cell size decreasing. Because of the intergrain exchange coupling, the coercivity mechanism is determined by the difference in magnetocrystalline anisotropy between the cell phase and the cell boundary phase. And the coercivity mechanism is related to not only the cells alignment but also temperature. With temperature increasing, a transformation of the demagnetization mechanism occurs from the domain pinning to the uniform magnetization reversal mode and the transformation temperature is about 650 K.

  18. Giant magnetoimpedance effect in Fe75.5Cu1Nb3Si13.5B7 ribbon/FeGa film composite

    Science.gov (United States)

    Zhang, Yi; Gan, Tao; Wang, Tao; Wang, Feifei; Shi, Wangzhou

    2016-11-01

    Optimized giant magnetoimpedance effect of Fe75.5Cu1Nb3Si13.5B7 amorphous ribbon/Fe80Ga20 film composites has been investigated. FeCuNbSiB amorphous ribbons as the substrates are commercially available, magnetostrictive FeGa films are deposited on one or both sides of the ribbons by ion-beam sputtering. Compared with the GMI curves without FeGa layer, the GMI effect of FeCuNbSiB amorphous ribbon has been obviously improved with FeGa film covered (from 4% to 16%). Moreover, the details exhibit an interesting phenomenon: at a certain frequency, when the FeGa film covered on one side of the ribbon, the GMI ratio decreases with the thickness of the FeGa film; however, when the FeGa films covered on both sides of the ribbon, the GMI ratio increases with the thickness of the FeGa film. We mainly attribute the reason to strain-induced anisotropy, which is induced by magnetostrictive effect under a longitudinal applied magnetic field.

  19. Effects of Ge substitution on the structural and physical properties of CuFeO2 delafossite oxide

    Science.gov (United States)

    Naka-in, Lerdkead; Kamwanna, Teerasak; Srepusharawoot, Pornjuk; Pinitsoontorn, Supree; Amornkitbamrung, Vittaya

    2015-04-01

    Delafossite CuFe1-xGexO2 (0.0 ≤ x ≤ 0.1) semiconductors were synthesized by solid-state reaction. The effects of Ge concentration on microstructural, optical, magnetic and electrical properties were investigated. X-ray diffraction (XRD) analysis results reveal the delafossite structure of all the samples. The lattice spacing of CuFe1-xGexO2 decreased with increasing substitution of Ge at the Fe site. The optical properties measured at room temperature by UV-visible spectroscopy showed an absorption peak at 283 nm (4.38 eV). The corresponding direct optical band gap was found to decrease with increasing Ge content (from 3.69 eV for x = 0 to 3.61 eV for x = 0.10), exhibiting transparency in the visible region. The magnetic hysteresis loops measured at room temperature showed that the Ge-doped CuFeO2 samples exhibit ferromagnetic behavior. The Curie temperature suggests that ferromagnetism originates from CuFe1-xGexO2 matrices. The substitution of Fe3+ by Ge4+ produces a mixed effect on the magnetic properties of CuFeO2 delafossite oxide. The resistivity of CuFe0.99Ge0.01O2 was observed to be ˜0.1 Ω·cm at room temperature.

  20. Crystal structure and physical properties of conducting molecular antiferromagnets with a halogen-substituted donor: (EDO-TTFBr2)2FeX4 (X = Cl, Br).

    Science.gov (United States)

    Miyazaki, A; Yamazaki, H; Aimatsu, M; Enoki, T; Watanabe, R; Ogura, E; Kuwatani, Y; Iyoda, M

    2007-04-16

    The crystal structure and physical properties of radical ion salts (EDO-TTFBr2)2FeX4 (X = Cl, Br) based on halogen-substituted organic donor and magnetic anions are investigated, including the comparison with the isomorphous compounds (EDO-TTFBr2)2GaX4 with nonmagnetic anions. The crystal structure of these four salts consists of uniformly stacked donor molecules and tetrahedral counter anions, and the Br substituents of the donor molecules are connected to halide ligands of anions with remarkably short intermolecular atomic distances. These salts show metallic behavior around room temperature and undergo a spin-density-wave transition in the low-temperature range, as confirmed with the divergence of the electron spin resonance (ESR) line width. Although close anion-anion contacts are absent in these salts, the FeCl4 salt undergoes an antiferromagnetic transition at TN = 4.2 K, and the FeBr4 salt shows successive magnetic transitions at TN = 13.5 K and TC2 = 8.5 K with a helical spin structure as a candidate for the ground state of the d-electron spins. The magnetoresistance of the FeCl4 salt shows stepwise anomalies, which are explained qualitatively using a pi-d interaction-based frustrated spin system model composed of the donor pi-electron and the anion d-electron spins. Although on the ESR spectra of the FeX4 salts signals from the pi- and d-electron spins are separately observed, the line width of the pi-electron spins broadens under the temperature where the susceptibility deviates from the Curie-Weiss behavior, showing the presence of the pi-d interaction.

  1. Chemistry and electronic properties of ferromagnetic metal-organic semiconductor interfaces: Fe on CuPc

    Energy Technology Data Exchange (ETDEWEB)

    Aristov, V.Yu. [IFW Dresden, 01069 Dresden (Germany); Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Molodtsova, O.V.; Knupfer, M. [IFW Dresden, 01069 Dresden (Germany); Ossipyan, Yu.A. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow distr., 142432 (Russian Federation); Doyle, B.P. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, 2006 (South Africa); Nannarone, S. [TASC-INFM Laboratory, Area Science Park - Basovizza, 34012 Trieste (Italy); Dipartimento di Ingegneria dei Materiali ed Amb., Universita di Modena e Reggio Emilia (Italy)

    2009-12-15

    The chemistry and electronic properties of the interfaces formed between the ferromagnetic metal (Fe) and the model organic semiconductor copper phthalocyanine are investigated in ultra-high vacuum conditions for the case of metal deposition onto the organic molecular thin film. The studies were performed by means of core-level and valence-band high-resolution photoemission electron spectroscopy (PES) as well as near-edge X-ray absorption fine structure using synchrotron radiation. Metal overlayer formation on the top of the organic semiconductor was observed without substantial penetration of deposited metal species into the organic film. At the thin interface layer the ferromagnetic metal shows strong chemical interaction with the nitrogen and carbon of the organic films. Moreover, our results infer that, as a consequence of Fe deposition onto CuPc, central copper atoms of the organic molecules at the interface are reduced from Cu(II) to Cu(I), while Fe atoms are oxidized and/or the ferromagnetic metal replaces this central Cu atom. Further optimization of such an interface is thus required to allow and/or facilitate the injection of spin-polarized carriers into organic semiconductors. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  2. Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

    CERN Document Server

    Ghosh, S; Petrelli, A; Kriegel, I; Gaspari, R; Almeida, G; Bertoni, G; Cavalli, A; Scotognella, F; Pellegrino, T; Manna, L

    2016-01-01

    We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor ce...

  3. Bandgap narrowing in the layered oxysulfide semiconductor Ba3Fe2O5Cu2S2: Role of FeO2 layer

    Science.gov (United States)

    Han, Zhang; Shifeng, Jin; Liwei, Guo; Shijie, Shen; Zhiping, Lin; Xiaolong, Chen

    2016-02-01

    A new layered Cu-based oxychalcogenide Ba3Fe2O5Cu2S2 has been synthesized and its magnetic and electronic properties were revealed. Ba3Fe2O5Cu2S2 is built up by alternatively stacking [Cu2S2]2- layers and iron perovskite oxide [(FeO2)(BaO)(FeO2)]2- layers along the c axis that are separated by barium ions with Fe3+ fivefold coordinated by a square-pyramidal arrangement of oxygen. From the bond valence arguments, we inferred that in layered CuCh-based (Ch = S, Se, Te) compounds the +3 cation in perovskite oxide sheet prefers a square pyramidal site, while the lower valence cation prefers the square planar sites. The studies on susceptibility, transport, and optical reflectivity indicate that Ba3Fe2O5Cu2S2 is an antiferromagnetic semiconductor with a Néel temperature of 121 K and an optical bandgap of 1.03 eV. The measurement of heat capacity from 10 K to room temperature shows no anomaly at 121 K. The Debye temperature is determined to be 113 K. Theoretical calculations indicate that the conduction band minimum is predominantly contributed by O 2p and 3d states of Fe ions that antiferromagnetically arranged in FeO2 layers. The Fe 3d states are located at lower energy and result in a narrow bandgap in comparison with that of the isostructural Sr3Sc2O5Cu2S2. Project supported by the National Natural Science Foundation of China (Grant Nos. 51472266, 51202286, and 91422303), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB07020100) and the ICDD.

  4. Disorder-induced gap in the normal density of states of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br.

    Science.gov (United States)

    Diehl, Sandra; Methfessel, Torsten; Tutsch, Ulrich; Müller, Jens; Lang, Michael; Huth, Michael; Jourdan, Martin; Elmers, Hans-Joachim

    2015-07-01

    The local density of states (DOS) of the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br, measured by scanning tunneling spectroscopy on in situ cleaved surfaces, reveals a logarithmic suppression near the Fermi edge persisting above the critical temperature T(c). The experimentally observed suppression of the DOS is in excellent agreement with a soft Hubbard gap as predicted by the Anderson-Hubbard model for systems with disorder. The electronic disorder also explains the diminished coherence peaks of the quasi-particle DOS below T(c).

  5. Theoretical study of the superhyperfine parameters for Cu{sup 2+} in K{sub 2}PdX{sub 4} (X = Cl, Br)

    Energy Technology Data Exchange (ETDEWEB)

    Wei, L. H.; Wu, S. Y., E-mail: shaoyi_wu@163.com; Zhang, Z. H.; Wang, X. F.; Hu, Y. X. [University of Electronic Science and Technology of China, Department of Applied Physics (China)

    2008-01-15

    The superhyperfine parameters T{sub j} (j = x, y, z) for Cu{sup 2+} in the square-planar K{sub 2}PdX{sub 4} (X = Cl, Br) are theoretically studied from the perturbation formulas of these parameters for an octahedral 3d{sup 9} cluster, by considering both the contributions from the crystal-field and charge-transfer mechanisms. The related molecular orbital coefficients are determined from the cluster approach in a uniform way. Based on one adjustable proportional factor {rho} for the orbital admixture coefficients, the calculated results of present work show reasonable agreement with the observed values.

  6. Influence of Cu on the catalytic activity of FeBEA zeolites in SCR of NO with NH 3

    OpenAIRE

    Boroń, Paweł; Chmielarz, Lucjan; Dzwigaj, Stanislaw

    2015-01-01

    International audience; Two series of Fe and/or Cu containing BEA zeolites were prepared by different procedures: two-step postsynthesis method (FexSiBEA, CuxSiBEA and FexCuxSiBEA) and conventional wet impregnation (FexHAlBEA, CuxHAlBEA and FexCuxHAlBEA) (x = 1.0 Fe or Cu wt%). Modification of BEA zeolite resulted in the incorporation of iron and/or copper into vacant T-atom sites of the zeolite framework as evidenced by XRD and DR UV–vis. Transition metals (Cu or Fe) were incorporated into t...

  7. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian, E-mail: chenjian@xatu.edu.cn [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Niu, Pengyun; Wei, Ting [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Hao, Liang [College of Architecture and Civil Engineering, Xi' an University of Science and Technology, Xi' an 710054 (China); Liu, Yunzi [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Wang, Xianhui, E-mail: xhwang693@xaut.edu.cn [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Peng, Yuli [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China)

    2015-11-15

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites.

  8. Development and characterization of the CU ground MAX-DOAS instrument: lowering RMS noise and first measurements of BrO, IO, and CHOCHO near Pensacola, FL

    Science.gov (United States)

    Coburn, S.; Dix, B.; Sinreich, R.; Volkamer, R.

    2011-01-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer O4 in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is directly proportional to the root mean square (RMS) of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS values of ~6 × 10-6 without apparent limitations other than photon shot noise. Laboratory tests revealed two factors that, in practice, limit the RMS: (1) detector non-linearity noise, RMSNLin, and (2) temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines) and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (~10-3) yet - unless actively controlled - is sufficiently large to create a RMSNLin limit of up to 1.4 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels/°C at 334 nm), and temperature variations of 0.1 °C can cause residual RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. The CU GMAX-DOAS was set up at a coastal site near Pensacola, FL, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL), with daytime average tropospheric vertical column densities, VCDs, of ~2 × 1013 molec cm-2, 8 × 1012 molec cm-2 and 4 × 1014 molec cm-2, respectively. HCHO and NO2 were also detected with typical MBL VCDs of 1 × 1016 and 3 × 1015. These are the first measurements of BrO, IO and CHOCHO over the Gulf of Mexico. The atmospheric implications of these observations for elevated mercury wet deposition rates in this area are briefly

  9. Study of polyaniline coated CuFe2O4 nanoparticles and their application in biosensor

    Science.gov (United States)

    Sharma, Uma Shankar; Shah, Rashmi

    2016-05-01

    Polyaniline coated with nanoferrite particles has attractive application in enzyme less biosensor. In this paper, we have reported the synthesis of copper ferrite by Chemical Coprecipitation method and polymerization of polyaniline by oxidation method. The polyaniline-ferrite composite was characterized by different techniques such as XRD and VSM. The XRD pattern confirmed the presence of cubic phase and particles size in nano scale. The magnetic properties were studied by vibrating sample magnetometer (VSM) technique at room temperature. The higher values of saturation magnetization attributed to the cation distribution change from normal to spinel structure. Some Fe3+ ions drifted from octahedral site to tetrahedral site through the conversion of some Fe2+ ions to Fe3+ ions with super-exchange interactions and gives rise to saturation magnetization. The saturation magnetization of polyaniline coated CuFe2O4 using ammonium nitrate is much less than by polyaniline coated CuFe2O4 using ammonium peroxidisulphate. The saturation magnetization Ms of the nanocomposite is dependent on the volume fraction of the magnetic ferrite particles and on the contribution of the non-magnetic polyaniline coated layer. Polyaniline worked as an immobilization layer in the enzyme less biosensor because enzyme less biosensor is not affected by environmental factor.

  10. Discovery of Cu-Ni-Zn-Sn-Fe intermetailic compounds and S-bearing alloys in the Zhaishang gold deposit,southern Gansu Province and its geological sisnificance

    Institute of Scientific and Technical Information of China (English)

    LIU JiaJun; MAO GuangJian; MA XingHua; LI LiXing; GUO YuQian; LIU GuangZhi

    2008-01-01

    Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

  11. Discovery of Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloys in the Zhaishang gold deposit, southern Gansu Province and its geological significance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Examination of ores by optical microscope and EPMA from the Zhaishang gold deposit, southern Gansu Province, has revealed an abundance of rare minerals. These include native metals, Cu-Ni-Zn-Sn-Fe polymetallic compounds and S-bearing alloys of Ni, Fe, Zn, Cu and Sn, occurring as native nickel, Zn-Cu alloy, Ni-Zn-Cu alloy, Sn-Zn-Ni-Cu alloy, Zn-Cu-Ni alloy, Zn-Fe-Cu-Sn-Ni alloy, Fe-Ni-S alloy, Sn-Fe-Ni-S alloy, Fe-Zn-Cu-Ni-S alloy, Zn-Ni-Cu-Fe-S alloy and others. Compared with the Zn-Cu alloy minerals discovered previously, these Zn-Cu minerals fall in the α or α+β portion in Zn-Cu alloy phase diagram, and the α portion has higher Cu content. Cu-Ni-Zn-Sn-Fe intermetallic compounds and S-bearing alloy minerals have not been previously reported in the literature. These rare alloys formed in a strongly reducing environment with absent oxygen and low sulfur activities.

  12. GIANT MAGNETO-IMPEDANCE OF PATTERNED FeSiB/Cu/FeSiB TRI-LAYER FILMS

    Institute of Scientific and Technical Information of China (English)

    X.H. Mao; Y. Zhou; M.S. Wu; B.C. Cai

    2003-01-01

    Sensitive magnetic field sensor with good performances can be fabricated utilizing the giant magneto-impedance (GMI) effect of soft magnetic multi-layer thin films. The transverse and longitudinal GMI effect in patterned FeSiB/Cu/FeSiB tri-layer films with the change of external magnetic field and frequency were studied at the same time. The change of the impedance of the films with the external magnetic fieldand frequency was shown. Comparing the longitudinal and transverse effect, the transverse effect has a larger linear range from zero magnetic field to a quite large magnetic field at all frequencies, and the change still were not saturated until the external magnetic field reached 1.2×104A/m, which illustrated that the films can be utilized to detect larger magnetic fields than now presented GMI sensors.

  13. A New ZrCuSiAs-Type Superconductor: ThFeAsN.

    Science.gov (United States)

    Wang, Cao; Wang, Zhi-Cheng; Mei, Yu-Xue; Li, Yu-Ke; Li, Lin; Tang, Zhang-Tu; Liu, Yi; Zhang, Pan; Zhai, Hui-Fei; Xu, Zhu-An; Cao, Guang-Han

    2016-02-24

    We report the first nitrogen-containing iron-pnictide superconductor ThFeAsN, which is synthesized by a solid-state reaction in an evacuated container. The compound crystallizes in a ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters a = 4.0367(1) Å and c = 8.5262(2) Å at 300 K. The electrical resistivity and dc magnetic susceptibility measurements indicate superconductivity at 30 K for the nominally undoped ThFeAsN.

  14. Subsurface structure and magnetic parameters of Fe-Mo-Cu-B metallic glass

    Directory of Open Access Journals (Sweden)

    Miglierini Marcel

    2015-03-01

    Full Text Available Subsurface properties of 57Fe81Mo9Cu1B9 metallic glass were studied by conversion electron and conversion X-ray Mössbauer spectrometry. They were applied to both surfaces of the ribbons. Deviations in structural surface features are exhibited via different contents of crystalline phases, which were identified as bcc-Fe and magnetite. The presence of small ferromagnetic particles was also suggested from magnetic measurements. An influence of irradiation with 130-keV N+ ions on surface properties of the as-quenched alloy is also discussed.

  15. Kondo screening of the spin and orbital magnetic moments of Fe impurities in Cu

    Science.gov (United States)

    Joly, L.; Kappler, J.-P.; Ohresser, P.; Sainctavit, Ph.; Henry, Y.; Gautier, F.; Schmerber, G.; Kim, D. J.; Goyhenex, C.; Bulou, H.; Bengone, O.; Kavich, J.; Gambardella, P.; Scheurer, F.

    2017-01-01

    We use x-ray magnetic circular dichroism to evidence the effect of correlations on the local impurity magnetic moment in an archetypal Kondo system, namely, a dilute Cu:Fe alloy. Applying the sum rules on the Fe L2 ,3 absorption edges, the evolution of the spin and orbital moments across the Kondo temperature are determined separately. The spin moment presents a crossover from a nearly temperature-independent regime below the Kondo temperature to a paramagneticlike regime above. Conversely, the weak orbital moment shows a temperature-independent behavior in the whole temperature range, suggesting different Kondo screening temperature scales for the spin and orbital moments.

  16. Preparation of Cu, Ag, Fe and Al nanoparticles by the exploding wire technique

    Indian Academy of Sciences (India)

    P Sen; Joyee Ghosh; Alqudami Abdullah; Prashant Kumar; Vandana

    2003-10-01

    We describe a novel process for the production of nanoparticles of Cu, Ag, Fe and Al which involves exploding their respective wires, triggered by large current densities in the wires. The particles are characterised by X-ray diffraction (XRD) and atomic force microscopy (AFM). Particle sizes in the range 20-100nm were obtained employing this technique. The XRD results reveal that the nanoparticles continue to retain lattice periodicity at reduced particle sizes, displaying in some cases evidence of lattice strain and preferential orientation. In the case of Fe, Mossbauer spectroscopy reveals loss of ferromagnetism as a result of the reduced size of the particles.

  17. Moessbauer study of a Fe-Zr-B-Cu-(Ge, Co) nanocrystalline alloy series

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez, J.S. [Departamento de Fisica de la Materia Condensada. ICMSE-CSIC. Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain); Franco, V. [Departamento de Fisica de la Materia Condensada. ICMSE-CSIC. Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain); Conde, A. [Departamento de Fisica de la Materia Condensada. ICMSE-CSIC. Universidad de Sevilla, Apartado 1065, 41080 Sevilla (Spain)]. E-mail: conde@us.es

    2006-09-28

    Amorphous and nanocrystalline Fe-Zr-B-Cu alloys with partial substitution of Co for Fe and Ge for B have been studied by Moessbauer spectrometry (MS). The compositional and microstructural dependence of the different hyperfine parameters were related to the results obtained by X-ray diffraction (XRD) and saturation magnetization measurements. Combination of MS and XRD leads to estimate an interface region, of thickness {approx}0.6 nm. The magnetic moment per transition metal of the crystalline phase is reduced with respect to binary crystalline alloys due to the existence of the interface.

  18. Enhancement of spin-Seebeck effect by inserting ultra-thin Fe{sub 70}Cu{sub 30} interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, D., E-mail: d.kikuchi@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Ishida, M.; Murakami, T. [Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Smart Energy Research Laboratories, NEC Corporation, Tsukuba 305-8501 (Japan); Uchida, K. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Qiu, Z. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Saitoh, E. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0076 (Japan)

    2015-02-23

    We report the longitudinal spin-Seebeck effects (LSSEs) for Pt/Fe{sub 70}Cu{sub 30}/BiY{sub 2}Fe{sub 5}O{sub 12} (BiYIG) and Pt/BiYIG devices. The LSSE voltage was found to be enhanced by inserting an ultra-thin Fe{sub 70}Cu{sub 30} interlayer. This enhancement decays sharply with increasing the Fe{sub 70}Cu{sub 30} thickness, suggesting that it is not due to bulk phenomena, such as a superposition of conventional thermoelectric effects, but due to interface effects related to the Fe{sub 70}Cu{sub 30} interlayer. Combined with control experiments using Pt/Fe{sub 70}Cu{sub 30} devices, we conclude that the enhancement of the LSSE voltage in the Pt/Fe{sub 70}Cu{sub 30}/BiYIG devices is attributed to the improvement of the spin-mixing conductance at the Pt/BiYIG interfaces.

  19. Microstructure of nano-crystalline material Al60Fe20Cu20%Al60Fe20Cu20纳米材料的结构研究

    Institute of Scientific and Technical Information of China (English)

    钱丽英; 朱春祥; 李彩霞; 贺博; 刘庆华; 郝绿原; 殷士龙

    2006-01-01

    采用机械合金化方法制备了系列Al60Fe20Cu20纳米晶体样品,并对部分样品附加500℃快速退火处理.联合使用X射线衍射和X射线吸收精细结构技术,分别从晶体的长程有序和原子近邻配位的短程有序2个方面研究样品的结构相变.结果表明:样品中Al和Cu原子首先组成体心四方结构的Al2Cu金属间化合物,然后与Fe原子合金化,形成Cu和简立方晶体结构AlFe的固溶体,结构稳定但不均匀,Fe原子处于富集状态;即使附加500℃-5 min退火,Al60Fe20Cu20系统在40h的机械合金化过程中不能形成准晶相;球磨30h后,晶粒尺寸已达到20nm左右.

  20. Technological Study of Electroless Ni-Cu-P Alloy Plating on Nd-Fe-B Magnet%Nd-Fe-B永磁体化学镀Ni-Cu-P工艺研究

    Institute of Scientific and Technical Information of China (English)

    于升学; 杨雪梅; 杨洪生

    2002-01-01

    本文研究了烧结型Nd-Fe-B永磁体化学镀Ni-Cu-P的工艺过程,Nd-Fe-B永磁体经除油、封孔、出光后直接化学镀Ni-Cu-P合金,可以获得与基体结合良好、耐蚀性高的镀层.

  1. Safe-by-Design CuO Nanoparticles via Fe-Doping, Cu-O Bond Length Variation, and Biological Assessment in Cells and Zebrafish Embryos.

    Science.gov (United States)

    Naatz, Hendrik; Lin, Sijie; Li, Ruibin; Jiang, Wen; Ji, Zhaoxia; Chang, Chong Hyun; Köser, Jan; Thöming, Jorg; Xia, Tian; Nel, Andre E; Mädler, Lutz; Pokhrel, Suman

    2017-01-24

    The safe implementation of nanotechnology requires nanomaterial hazard assessment in accordance with the material physicochemical properties that trigger the injury response at the nano/bio interface. Since CuO nanoparticles (NPs) are widely used industrially and their dissolution properties play a major role in hazard potential, we hypothesized that tighter bonding of Cu to Fe by particle doping could constitute a safer-by-design approach through decreased dissolution. Accordingly, we designed a combinatorial library in which CuO was doped with 1-10% Fe in a flame spray pyrolysis reactor. The morphology and structural properties were determined by XRD, BET, Raman spectroscopy, HRTEM, EFTEM, and EELS, which demonstrated a significant reduction in the apical Cu-O bond length while simultaneously increasing the planar bond length (Jahn-Teller distortion). Hazard screening was performed in tissue culture cell lines and zebrafish embryos to discern the change in the hazardous effects of doped vs nondoped particles. This demonstrated that with increased levels of doping there was a progressive decrease in cytotoxicity in BEAS-2B and THP-1 cells, as well as an incremental decrease in the rate of hatching interference in zebrafish embryos. The dissolution profiles were determined and the surface reactions taking place in Holtfreter's solution were validated using cyclic voltammetry measurements to demonstrate that the Cu(+)/Cu(2+) and Fe(2+)/Fe(3+) redox species play a major role in the dissolution process of pure and Fe-doped CuO. Altogether, a safe-by-design strategy was implemented for the toxic CuO particles via Fe doping and has been demonstrated for their safe use in the environment.

  2. Amorphous Fe72Cu1V4Si15B8 ribbon as magneto-impedance sensing element

    Directory of Open Access Journals (Sweden)

    Surla Radoslav

    2016-01-01

    Full Text Available Мagneto-impedance (MI effect in the Fe72Cu1V4Si15B8 amorphous ribbon obtained by melt spinning method has been studied. The aim of study was the characterisation of this ribbon in as-cast state in terms of its application as a MI sensor. The experiments on MI elements were performed in the frequency range from 30 kHz to 300 MHz and maximum external magnetic field up to 28.6 kA/m. Maximum observed MI-ratio (ΔZ = Z(0 - Z(Hmax, Hmax = 28.6 kA/m has amounted to ΔZ/Z(Hmax = 173% at a frequency of 20.46 MHz. The MI curve measured up to 20 MHz shows some shoulder indicating the growth of rotational contribution of magnetization that appears above the domain wall relaxation frequency. The MI profile at frequencies higher than 30 MHz, exhibits a clear peak positioned at transverse anisotropy field Hk, suggesting domination of rotation magnetization in transverse permeability. The linearity in the range up to 5 kA/m with sensitivity of about 11 %/kA/m was observed. [Projekat Ministarstva nauke Republike Srbije, br. OI 172057

  3. The adsorption and decomposition of methane on Fe/Cu(110)bimetallic surface

    Institute of Scientific and Technical Information of China (English)

    鲍世宁; 范朝阳; 李海洋; 徐亚伯

    1995-01-01

    The adsorption and decomposition of methane on Fe/Cu(110) bimetallic surface have been studied by HREELS and ARUPS. The results show that the activation energy of dissociative chemisorption for methane is reduced obviously by preadsorption of iron on copper surface. The chemisorption probability of methane is so high on Fe/Cu(110) bimetallic surface that chemisorption of methane can be observed at room temperature and low pressure. When the iron coverage is lower than 1 ML, the chemisorption probability increases linearly with increasing iron coverage. After the iron coverage is beyond 1 ML(<2ML) the probability continues increasing. The iron atom with disordered structure can offer the site of dissociative chemisorption to methane too. A hydroformyl species is formed through interaction between methane and the preadsorbed oxygen atoms. The reaction enhances the dissociative chemisorption of methane on the surface.

  4. Microstructure and Tribological Behaviour of CrCuFeNiTi High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Sobiyi Kehinde

    2016-01-01

    Full Text Available The microstructure, hardness and wear performance of CrCuFeTiNi high entropy alloy were evaluated. The alloy was produced by mixing constituent elements, consolidated and melted using vacuum arc furnace. The X-ray diffraction analysis confirmed that the alloy is composed of FCC and BCC simple phases. The microstructure contains three regions that were rich in Cu, Cr and Fe which resulted from segregation of constituent elements. The Vickers micro hardness of the alloy was determined as HV0.5 = 510 ± 7 MPa. The wear performance of the alloy was also studied using WC balls under two load conditions. The volume loss was evaluated, accompanied by analysis of the wear tracks and debris using SEM images and EDS. The main wear mechanisms were ploughing, adhesion and oxidation-dominated wear.

  5. THERMODYNAMICS OF FE-CU ALLOYS AS DESCRIBED BY A CLASSIC POTENTIALS

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A; Caro, M; Lopasso, E M; Turchi, P A; Farkas, D

    2005-04-14

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. (Modelling Simul. Mater. Sci. Eng. 6, 19 (1998)). In this work we extract thermodynamic information from this interatomic potentials. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials; finally we suggest an approach to improve existing potentials for this system.

  6. Synthesis and Magnetic Properties of CuFe2O4 Nanotube Arrays

    Institute of Scientific and Technical Information of China (English)

    GAO Hua; GAO Daqiang; ZHANG Jing; YANG Guijin; ZHANG Jinlin; SHI Zhenhua; XUE Desheng

    2012-01-01

    CuFe2O4 nanotube arrays with different outer diameters were synthesized in anodic aluminum oxide templates through sol-gel techniques followed by heating treatment processes.The morphology of the nanotube arrays was investigated by field emission scanning electron microscope and transmission electron microscopy,suggesting that the nanotube arrays are ordered and uniform.The X-ray diffraction results indicate that the crystal structure of the nanotube arrays is polycrystalline with a spinel-type structure.The measurements of magnetic properties indicate that CuFe2O4 nanotube arrays with outer diameter of 200 nm exhibit magnetic anisotropy with easy magnetization direction along the axis of nanotubes.

  7. Evaluation of Fracture Toughness of Al-Cu-Fe-B Quasicrystal

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xi-ying; LI Pei-yao; QIAN Shi-qiang

    2003-01-01

    Vickers indentation test,a simple method for the toughness determination,is used to test the fracture toughness of Al59Cu25.5Fe12.5B3 polycrystalline quasicrystal.According to the profiles of the indentation,the radial crack size and related equation,the microhardness Hv, Young's modulus E,cracking threshold,and fracture toughness have been evaluated.The results show that the Young's modulus of Al-Cu-Fe-B polycrystalline quasicrystal is evaluated as 134GPa,and the fracture toughness is about 1.36 MPa*m-1/2.For the Vickers indenter,the cracking threshold is in the range of 250MN-500MN.Moreover,the surface morphology of the indentations and the cracks are observed by means of Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM).The relationship between the microstructure of quasicrystal and crack initiation and propagation is discussed in detail.

  8. Revised magnetic properties of CuFeO{sub 2}-a case of mistaken identity

    Energy Technology Data Exchange (ETDEWEB)

    Petrenko, O A [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Lees, M R [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Balakrishnan, G [University of Warwick, Department of Physics, Coventry CV4 7AL (United Kingdom); Brion, S de [Grenoble High Magnetic Field Laboratory, CNRS and MPI-FKF, BP166, 38042 Grenoble Cedex 9 (France); Chouteau, G [Grenoble High Magnetic Field Laboratory, CNRS and MPI-FKF, BP166, 38042 Grenoble Cedex 9 (France)

    2005-05-04

    We propose a new model for the understanding of the magnetic properties of CuFeO{sub 2}, which differs significantly from the generally accepted two-dimensional Ising model. We show that a Heisenberg model with a relatively weak anisotropy gives a much better description of all the magnetic data available for CuFeO{sub 2}. The model is self-consistent; it allows one to determine for the first time a set of parameters for the exchange interactions and magnetic anisotropy in this frustrated magnetic system. The model is backed up by single-crystal measurements of susceptibility, magnetization and specific heat as a function of magnetic field and temperature.

  9. Magnetic and Hardness Analysis During Precipitation and Recovery Process of Deformed Fe-Cu Alloy

    Science.gov (United States)

    Kikuchi, Hiroaki; Sasaki, Takahiro; Murakami, Takeshi; Ito, Fumiya

    This paper describes the characteristics of the coercive force and Vickers hardness for cold-rolled and thermally aged Fe-Cu alloys with varying isothermal aging times. Fe-1 wt% Cu alloys were cold-rolled and then thermally aged at 553 or 773 K from 0 to 104 min. The coercive force for the cold-rolled specimen decreases with increasing aging time, and the slope of the reduction becomes higher with increasing aging temperature. The recovery process contributes to the change in the coercive force. In contrast, the hardness increases with increasing aging time at an early aging stage and then eventually peaks. The copper precipitates play an important role in the change in the hardness and barely have an effect on the magnetic properties.

  10. Study of structural and optical properties of Fe doped CuO nanoparticles

    Science.gov (United States)

    Rani, Poonam; Gupta, Ankita; Kaur, Sarabjeet; Singh, Vishal; Kumar, Sacheen; Kumar, Dinesh

    2016-05-01

    Iron doped Copper oxide nanoparticles were synthesized by the co-precipitation method at different concentration (3%, 6%, 9%) at 300-400° C with Copper Acetate and Ferric Chloride as precursors in presence of Polyethylene Glycol and Sodium Hydroxide as stabilizing agent. Effect of doping on the structural and optical properties is studied. The obtained nanoparticles were characterized by X-Ray Diffraction and UV-Visible Spectroscopy for examining the size and the band gap respectively. The X-Ray Diffraction plots confirmed the monoclinic structure of Copper oxide suggesting the Cu atoms replaced by Fe atoms and no secondary phase was detected. The indirect band gap of Fe doped CuO nanoparticles is 2.4eV and increases to 3.4eV as the concentration of dopant increases. The majority of particle size is in range 8 nm to 35.55 nm investigated by X-ray diffractometer.

  11. Surfactant-assisted epitaxial growth and magnetism of Fe films on Cu(111)

    Energy Technology Data Exchange (ETDEWEB)

    Nino, M A; Camarero, J; Miguel, J J de; Miranda, R [Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales ' Nicolas Cabrera' , Universidad Autonoma de Madrid, Cantoblanco, 28049-Madrid (Spain); Gomez, L [Facultad de Ciencias Exactas, IngenierIa y Agrimensura, Instituto de Fisica Rosario, 2000-Rosario (Argentina); Ferron, J [Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Departamento de Materiales, Facultad de IngenierIa Quimica, UNL, 3000 Santa Fe (Argentina)

    2008-07-02

    The magnetic properties of thin epitaxial layers of Fe grown on Cu(111) depend sensitively on the films' structure and morphology. A combination of experiments and numerical simulations reveals that the use of a surfactant monolayer (ML) of Pb during molecular beam epitaxy (MBE) growth at room temperature reduces the amount of interdiffusion at the Cu-Fe interface, retards the fcc-to-bcc transformation by about 2 ML and substantially increases the films' coercivity. The origin of all these alterations to the magnetic behavior can be traced back to the structural modifications provoked by the surfactant during the early growth stages. These results open the way for the controlled fabrication of custom-designed materials with specific magnetic characteristics.

  12. Dilute Magnetic Semiconductor Cu2FeSnS4 Nanocrystals with a Novel Zincblende Structure

    Directory of Open Access Journals (Sweden)

    Xiaolu Liang

    2012-01-01

    Full Text Available Diluted magnetic semiconductor Cu2FeSnS4 nanocrystals with a novel zincblende structure have been successfully synthesized by a hot-injection approach. Cu+, Fe2+, and Sn4+ ions occupy the same position in the zincblende unit cell, and their occupancy possibilities are 1/2, 1/4, and 1/4, respectively. The nanocrystals were characterized by means of X-ray diffraction (XRD, transmission electron microscopy (TEM, selected area electron diffraction (SAED, energy-dispersive spectroscopy (EDS, and UV-vis-NIR absorption spectroscopy. The nanocrystals have an average size of 7.5 nm and a band gap of 1.1 eV and show a weak ferromagnetic behavior at low temperature.

  13. Enthalpy of formation of quasicrystalline phase and ternary solid solutions in the Al-Fe-Cu system

    Institute of Scientific and Technical Information of China (English)

    I.A. Tomilin; S.D. Kaloshkin; V. V. Tcherdyntsev

    2006-01-01

    Standard enthalpies of formation of quasicrystalline phase and the ternary solid solutions in the Al-Fe-Cu system and the intermetallic compound FeAl were determined by the means of solution calorimetry. The quasicrystalline phase was prepared using two different methods. The first method (Ⅰ) consisted of ball milling the mixture of powders of pure aluminum copper and iron in a planetary mill with subsequent compacting by hot pressing and annealing. The second method (Ⅱ) consisted of arc melting of the components in argon atmosphere followed by annealing. The latter method was used for preparing the compound FeAl and the solid solutions. The phases were identified using the XRD method. The enthalpy of the formation was determined for the quasicrystalline phase of the composition Al62Cu25.5Fe12.5 and the ternary BCC solid solutions Al35Cu14Fe51, Al40Cu17Fe43, and Al50.4Cu19.6Fe30. The measured enthalpy of formation of the intermetallic com pound FeAl is in good agreement with the earlier published data. The enthaipies of formation of the quasicrystalline phases prepared using two different methods are close to each other, namely, -22.7±3.4 (method Ⅰ) and -21.3±2.1 (method Ⅱ)k J/mol.

  14. Structure and energetics of high index Fe, Al, Cu and Ni surfaces using equivalent crystal theory

    Science.gov (United States)

    Rodriguez, Agustin M.; Bozzolo, Guillermo; Ferrante, John

    1993-01-01

    Equivalent crystal theory (ECT) is applied to the study of multilayer relaxations and surface energies of high-index faces of Fe, Al, Ni, and Cu. Changes in interplanar spacing as well as registry of planes close to the surface and the ensuing surface energies changes are discussed in reference to available experimental data and other theoretical calculations. Since ECT is a semiempirical method, the dependence of the results on the variation of the input used was investigated.

  15. Electrodeposition and characteristics of Ni{sub 80}Fe{sub 20}/Cu composite wires

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.P. [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore) and Division of Bioengineering, National University of Singapore, Singapore 119260 (Singapore)]. E-mail: mpelixp@nus.edu.sg; Seet, H.L. [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore); Fan, J. [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore); Yi, J.B. [Department of Mechanical Engineering, National University of Singapore, Singapore 119260 (Singapore)

    2006-09-15

    Electrodeposited Ni{sub 80}Fe{sub 20}/Cu composite wire has significant advantages over amorphous wire as sensing element for weak magnetic field sensors, such as orthogonal fluxgate sensors, due to its non-ferromagnetic and conductive core structure. In this study, the key processing parameters are investigated, including electrodeposition current density, duty cycle, electrolyte solution, pH value, applied magnetic field, effect of seeded layers, and post annealing.

  16. Structural ordering of laser-processed FePdCu thin alloy films

    Energy Technology Data Exchange (ETDEWEB)

    Perzanowski, Marcin, E-mail: Marcin.Perzanowski@ifj.edu.pl; Krupinski, Michal; Zarzycki, Arkadiusz; Zabila, Yevhen; Marszalek, Marta

    2015-10-15

    The Cu/Fe/Pd multilayers were transformed into L1{sub 0}-ordered FePdCu alloy by pulsed laser annealing. The initial multilayers were irradiated with 1, 10, 100, and 1000 laser pulses with duration time of 10 ns and energy density of 235 mJ/cm{sup 2}. The gradual change of the number of laser pulses allowed to investigate the structural and magnetic properties at early stages of the transformation and L1{sub 0}-ordering processes. The measurements were carried out using X-Ray Diffraction, SQUID magnetometry, and Magnetic Force Microscopy. We found that L1{sub 0} FePdCu (111)-oriented nanograins are formed by ordering of the coherent domains present in the as-deposited multilayer. The irradiation does not change the vertical size of the (111) crystallites. The L1{sub 0} (002)-oriented grains appear at the later stages of the transformation and their size increases with the number of applied laser pulses. Additionally, the laser annealing induces the magnetic ordering of the irradiated material, which was observed as an increase of the saturation magnetisation and the Curie temperature with the rising number of pulses. We also observed, that irradiation with 1000 pulses leads to the loss of order, which is reflected in the drop of the Curie temperature. - Highlights: • L1{sub 0}-ordered FePdCu alloy successfully fabricated by laser annealing. • The mechanism of (111) and (002) nanocrystallite formation was different. • Gradual change of annealing conditions showed early stages of transformation. • Saturation magnetisation and Curie temperature increased with the number of pulses.

  17. Pressure stress-impedance effect in FeCuNbSiB amorphours ribbons

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The stress-impedance effect in Fe73.5Cu1Nb3Si13.5B9 (at%) ribbons is measured to investigate the influences of vacuum annealing and pressure stress. The results can be explained by the influence of induced anisotropy in the magnetization processes at the chosen drive current frequency of 90 MHz. The maximum SI% value of the ribbon annealed at 300 ℃ is 2.52%.

  18. Density Of The Copper-Rich Cu-Pb-Fe Alloys

    Directory of Open Access Journals (Sweden)

    Sak T.

    2015-09-01

    Full Text Available Density of the copper-rich corner of the ternary Cu-Pb-Fe alloys was determined with the dilatometric method. Investigated alloys had constant copper content equal to 0.9, 0.8 and 0.7 mole fraction, and varied iron concentration up to 0.1 mole fraction. A model predicting the density of ternary solution from knowledge of density of pure component and the excess of molar volume for limiting binaries is proposed.

  19. Nanoindentation deformation of a bi-phase AlCrCuFeNi{sub 2} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yuan [School of Mechanical Engineering, Shanghai Dianji University, 200245 Shanghai (China); Zhao, Guangfeng [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Wen, Xiyu [Center for Aluminum Technology, University of Kentucky, Lexington, KY 40511 (United States); Qiao, Junwei [Taiyuan University of Technology, Taiyuan, 030024 (China); Yang, Fuqian, E-mail: fyang0@engr.uky.edu [Materials Program, Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)

    2014-09-01

    Highlights: • The AlCrCuFeNi{sub 2} HEA consisted of BCC solid solution and FCC solid solution. • The indentation hardness of the BCC crystals is larger than the FCC crystals. • The contact modulus of the FCC crystals is larger than the BCC crystals. - Abstract: High-entropy alloys (HEA) are multicomponent alloys with lattice structures, which have unique mechanical properties. Using X-ray diffraction, the structure of as cast AlCrCuFeNi{sub 2} HEA was characterized. The AlCrCuFeNi{sub 2} HEA consisted of body centered-cubic (BCC) solid solution and face centered-cubic (FCC) solid solution. Nanoindentation was used to characterize the indentation deformation of the FCC and BCC crystals in the AlCrCuFeNi{sub 2} HEA. Both the indentation hardness and the contact modulus of the FCC and BCC crystals decreased slightly with the increase in the indentation load and became constant for large indentation loads. For the indentation load larger than 500 μN, the contact modulus and the indentation hardness of the BCC crystals are 146 and 4.6 GPa, respectively, and the contact modulus and the indentation hardness of the FCC crystals are 207 and 2.8 GPa, respectively. The plastic energy dissipated in the nanoindentation increased with the indentation load and was proportional to the 1.77 and 1.88 power of the indentation load for the FCC and BCC crystals, respectively. The ratio of the dissipated plastic energy to the total energy in the indentations was a linear function of the ratio of the residual indentation depth to the corresponding maximum indentation depth. The slope of the energy ratio verse the indentation depth ratio for the BCC crystals is larger than that for the FCC crystals.

  20. Cavitation Erosion Behavior of as-Welded Cu12Mn8Al3Fe2Ni Alloy

    Institute of Scientific and Technical Information of China (English)

    Xiaoya LI; Yonggui YAN; Zhenming XU; Jianguo LI

    2004-01-01

    Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied by magnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance of the as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass loss and the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysis of eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-welded one. Microcracks causing cavitation damage initiate at the phase boundaries.

  1. Sonocatalytic Methylene Blue in The Presence of Fe3O4-CuO-TiO2 Nanocomposites Heterostructure

    Science.gov (United States)

    Fauzian, Malleo; Jalaludin, Shofianina; Taufik, Ardiansyah; Saleh, Rosari

    2016-04-01

    In this work, the emphasis was mainly placed on investigating the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The prepared samples were characterized by X-ray diffraction (XRD), Vibrating Sample Magnetometer (VSM), Brunauer-Emmett-Teller (BET) Surface Area Analysis. Methylene blue dye was selected to examine the sonocatalytic activity of Fe3O4-CuO-TiO2 nanocomposites heterostructure. The degradation reaction processes were monitored by UV-vis spectrophotometer. The influence on the activity of the Fe3O4-CuO-TiO2 nanocomposites heterostructure such as TiO2 loading was studied. The sonocatalyst Fe3O4-CuO-TiO2 with molar ratio of 1:1:5 showed the highest sonocatalytic activity. At last, the experiment also indicated that holes are the main reactive species in the photodegradation mechanism in methylene blue.

  2. High capacity and high rate capability of nanostructured CuFeO 2 anode materials for lithium-ion batteries

    Science.gov (United States)

    Lu, Lin; Wang, Jia-Zhao; Zhu, Xue-Bin; Gao, Xuan-Wen; Liu, Hua-Kun

    Non-toxic, cheap, nanostructured ternary transition metal oxide CuFeO 2 was synthesised using a simple sol-gel method at different temperatures. The effects of the processing temperature on the particle size and electrochemical performance of the nanostructured CuFeO 2 were investigated. The electrochemical results show that the sample synthesised at 650 °C shows the best cycling performance, retaining a specific capacity of 475 mAh g -1 beyond 100 cycles, with a capacity fading of less than 0.33% per cycle. The electrode also exhibits good rate capability in the range of 0.5 C-4 C. At the high rate of 4 C, the reversible capacity of CuFeO 2 is around 170 mAh g -1. It is believed that the ternary transition metal oxide CuFeO 2 is quite acceptable compared with other high performance nanostructured anode materials.

  3. Synthesis of copper–ferrous (CuFe) nanowires via electrochemical method and its investigations as a fluid sensor

    Indian Academy of Sciences (India)

    Saleem Khan; Sandeep Arya; Parveen Lehana; Suresh Kumar

    2014-06-01

    The special behaviour of nanowires with respect to electrical conductivity makes them suitable for sensing application. In this paper, we present a copper–ferrous (CuFe) nanowires based sensor for detection of chemicals. CuFe nanowires were synthesized by template-assisted electrochemical method. By optimizing the deposition parameters, continuous nanowires on a copper substrate were synthesized. The morphological and structural studies of the synthesized CuFe nanowires were carried out using scanning electron microscope (SEM) and X-ray diffraction (XRD). Substrates containing CuFe nanowires were moulded to form a capacitor. Different chemicals were used as dielectric in the capacitor which showed that the capacitance was a nonlinear function of the dielectric constant of fluid unlike the linear relation shown by conventional capacitors. This unique property of the nanowires based capacitors may be utilized for developing fluid sensors with improved sensitivity.

  4. Studies of De-excited Spectra of Heavy Ions FeI and CuI at Low Energy

    Institute of Scientific and Technical Information of China (English)

    王友德; 杨治虎; 马新文; 徐谦; 刘惠萍; 赵孟春

    1994-01-01

    The de-excited spectra of FeI and CuI after the interaction of Fe+ and Cu+ ions with a carbon foil (8.5μg/cm2) have been investigated by using the Beam-foil(BF) technique at an incident energy of 110 keV.The measured lines in the spectra are mainly from de-excited atoms FeI and CuI.The lifetime of stronger lines,including seven lines of FeI and three lines of CuI of the spectra are also measured.Some progress has been made in preparing foils with high quality and in adjusting the intensity of ion beams During measurements,the lifetime of carbon foil targets is more than 30 minutes.

  5. Elastic properties and inter-atomic bonding in layered Fe-Cu arsenide oxide Sr{sub 2}Fe{sub 2}CuAs{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Shein, Igor R.; Bannikov, Vyacheslav V.; Ivanovskii, Alexander L. [Institute of Solid State Chemistry, Ural Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2011-09-15

    Inspired by recent discovery of the layered five-component phase - the tetragonal arsenide oxide Sr{sub 2}Fe{sub 2}CuAs{sub 2}O{sub 2} uniting two types of [Fe{sub 2}As{sub 2}] and [CuO{sub 2}] blocks, which are the main building blocks inherent in two basic families of high-T{sub C} superconductors: so-called cuprates and iron-pnictides, we used the first principles calculations to predict the elastic properties and to find their interplay with inter-atomic bonding for this unique system. Our data reveal that the examined phase is a relatively soft material; the predicted bulk and shear modules are about 90 and 54 GPa, respectively. Besides, this system is mechanically stable, adopts considerable elastic anisotropy, and should demonstrate brittleness. These conclusions agree with the bonding picture for Sr{sub 2}Fe{sub 2}CuAs{sub 2}O{sub 2}, according to which the inter-atomic bonding in this system is highly anisotropic and includes ionic, covalent, and metallic contributions, where inside [Fe{sub 2}As{sub 2}] and [CuO{sub 2}] blocks covalent-ionic Fe-As, Cu-O and metallic-like Fe-Fe bonds take place, whereas inter-blocks bonding is basically of the ionic type. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. The influence of Cu, Al, or Fe on the insulating capacity of CF3I

    Science.gov (United States)

    Xiao, Song; Cressault, Yann; Zhang, Xiaoxing; Teulet, Philippe

    2016-12-01

    SF6 is widely used in electrical equipment as an insulating medium. However, SF6 is a serious greenhouse gas. CF3I is considered as one of its potential alternatives. This study verifies whether free metal particle (Cu, Al, or Fe) defects adversely affect CF3I insulation and investigates the incidence from different types and numbers of metal particles. This study is also devoted to calculating specific heat at constant pressure and electrical conductivity of CF3I-metal mixtures. The calculation results prove that with the increase of metal ions, temperature rises faster in the CF3I-Cu plasma or in the CF3I-Fe plasma than in the CF3I plasma without metal absorbing the same energy. The fast development of ionization can promote the increase of free electrons and the rise of electric conductivity. On the basis of the experiments and theoretical analysis, the influence of Cu and Al on the insulating capacity of CF3I is greater than that of Fe.

  7. Theoretical Scanning Tunnelling Microscopy Images of Metal (Fe, Co, Ni and Cu) Phthalocyanines

    Institute of Scientific and Technical Information of China (English)

    李群祥; 朱清时; 袁岚峰; 杨金龙; 侯建国

    2001-01-01

    The scanning tunnelling microscopy (STM) images of isolated iron phthalocyanine (FePc), cobalt phthalocyanine (CoPc), nickel phthalocyanine (NiPc) and copper phthalocyanine (CuPc) are simulated theoretically. All the simulated STM images show submolecular structures and reproduce well the features of the experimental images. The results show that there is a strong dependence of the STM images on the ion valence configuration of the metal ion. At the small tip bias voltages of less than 0.5 V, the central metal ions in NiPc and CuPc appear as holes in the molecular images, while they are the highlighted bumps in FePc and CoPc. The simulated images are interpreted by the fact that both FePc and CoPc systems have a significant dz2 character near the Fermi level while the NiPc and CuPc systems do not. Moreover, we predict that the central nickel ion for NiPc appears as a highlighted point when the tip bias voltage is larger than 0.7 V.

  8. The structure and thermal parameters of ordered Cu65Fe10Pd25 ternary alloy

    Science.gov (United States)

    Ahmad, N.; Ziya, A. B.; Ibrahim, A.; Atiq, S.; Ahmad, S.; Bashir, F.

    2015-03-01

    Structural and thermal parameters have been studied in Cu65Fe10Pd25 alloy during order-disorder (O-D) transformation using differential scanning calorimetry (DSC) and high temperature X-ray diffraction (HTXRD). The results reveal that the Cu65Fe10Pd25 alloy undergoes an O-D transformation at Tc=797 K. The alloy shows L12 type ordering below Tc and has disordered face centered cubic (fcc) structure above Tc. The lattice parameter shows a positive deviation from Vegard's rule which may be related to the weakening of interatomic forces by the addition of Fe. The integrated intensity data obtained from the diffraction experiments was utilized to determine the coefficient of thermal expansion (α(T)), mean square amplitude of vibration (u2 bar (T)) and Debye temperatures (ΘD) during the O-D transformation. The abrupt change in the value of lattice parameter and coefficient of thermal expansion at Tc shows that the nature of O-D transition is first order. These results have been discussed by comparing them to those for Cu3Pd alloy.

  9. Structural phase transition in CuFe{sub 2}O{sub 4} spinel

    Energy Technology Data Exchange (ETDEWEB)

    Balagurov, A. M., E-mail: bala@nf.jinr.ru; Bobrikov, I. A.; Maschenko, M. S.; Sangaa, D.; Simkin, V. G. [Joint Institute for Nuclear Research (Russian Federation)

    2013-09-15

    A structural transition with a reduction in symmetry of the high temperature cubic phase (sp. gr. Fd3m) to the tetragonal phase (sp. gr. I4{sub 1}/amd) and the appearance of a ferrimagnetic structure occur in CuFe{sub 2}O{sub 4} copper ferrite at T Almost-Equal-To 440 Degree-Sign C. It is established by an experiment on a high-resolution neutron diffractometer that the temperature at which long-range magnetic order occurs is higher than that of tetragonal phase formation. When cooling CuFe{sub 2}O{sub 4} spinel from 500 Degree-Sign C, the equilibrium coexistence of both phases is observed in a fairly wide temperature range ({approx}40 Degree-Sign C). The composition studied is a completely inverse spinel in the cubic phase, and in the tetragonal phase the inversion parameter does not exceed few percent (x = 0.06 {+-} 0.04). At the same time, the phase formed upon cooling has a classical value of tetragonal distortion ({gamma} Almost-Equal-To 1.06). The character of temperature changes in the structural parameters during the transition from cubic to tetragonal phase indicates that this transition is based on the Jahn-Teller distortion of (Cu,Fe)O{sub 6} octahedra rather than the mutual migration of copper and iron atoms.

  10. Thermal Stability and Reductive Property of CexZr1-xO2 Solid Solution Doped Simultaneously by Fe, Mn or Fe, Cu

    Institute of Scientific and Technical Information of China (English)

    Yan Zhongjun; Yang Dong; Wen Mingfen; Chen Jing; Wang Jinggang; Gu Yongwan

    2005-01-01

    CexZr1-xO2 complex oxides doped by transition metal(Fe, Mn, Cu) were prepared by precipitation method. Thermal stability of samples was characterized by XRD, surface areas were measured by BET method and reductive property was characterized by TPR. The results show that MnO2 can be dispersed in solid solution after calcined at 1273 K, when the loading is 12%, while Fe and Cu is easy to separate from samples at this temperature. Samples doped simultaneously by Fe, Mn or Fe, Cu demonstrated high reactive property at low temperature. The starting reduction temperature are 413 and 373 K, respectively. TPR results also show a broad range of reductive temperature exists in these bi-metal doped samples.

  11. High near-infrared absorbing Cu5FeS4 nanoparticles for dual-modal imaging and photothermal therapy

    Science.gov (United States)

    Zhao, Qi; Yi, Xuan; Li, Meifang; Zhong, Xiaoyan; Shi, Quanliang; Yang, Kai

    2016-07-01

    Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments.Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe3+ doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (~10% ID g-1) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr04444a

  12. Microstructure and solidification behavior of multicomponent CoCrCu{sub x}FeMoNi high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wu, P.H. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Liu, N., E-mail: lnlynn@126.com [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Yang, W. [School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nanchang, Jiangxi 330063 (China); Zhu, Z.X. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China); Lu, Y.P. [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024 (China); Wang, X.J. [School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212003 (China)

    2015-08-26

    (Fe, Co, Ni) rich dendrites nucleate primarily in CoCrFeMoNi and CoCrCu{sub 0.1}FeMoNi alloys, followed by peritetic and eutectic reactions. The quasi-peritectic reaction occurs between the primary Mo-rich dendrites and liquids in the CoCrCu{sub 0.3}FeMoNi melts, and transfers to a eutectic coupled-growth at the edge of the quasi-peritectic structure. Subsequently, eutectic reaction happens in the remnant liquids. Liquid-phase separations have occurred in CoCrCu{sub x}FeMoNi alloys when x≥0.5. Meanwhile, some nanoscale precipitates are obtained in the Cu-rich region. Two crystal structures, FCC and BCC, are identified in CoCrCu{sub x}FeMoNi high entropy alloys. Amazingly, a pretty high plastic strain (51.6%) is achieved in CoCrCu{sub 0.1}FeMoNi alloy when the compressive strength reaches to 3012 Mpa. With the increase of Cu content, atomic size difference (ΔR) and electro-negativity difference (ΔX) decrease while valence electron concentration (VEC), mixing enthalpy (ΔH) and mixing entropy (ΔS) increase. Consequently, the valence electron concentration (VEC) values range for the formation of mixture of FCC and BCC structures can be enlarged to 6.87–8.35 based on the study of this paper. It is the positive enthalpies of mixing that causes the liquid-phase separation in CoCrCu{sub x}FeMoNi high entropy alloys.

  13. Short-range ferromagnetism in alloy ribbons of Fe-Cr-Si-Nb-(Ag, Cu)

    Energy Technology Data Exchange (ETDEWEB)

    THANH, P. Q.; HOA, N. Q.; CHAU, N. [Vietnam National University, Hanoi (Viet Nam); HUU, C. X. [Danang University of Technology, Danang (Viet Nam); NGO, D. T. [Technical University of Denmark, Kgs. Lyngby (Denmark); PHAN, T. L. [Chungbuk National University, Cheongju (Korea, Republic of)

    2014-04-15

    We have studied the magnetic properties of two amorphous alloy ribbons Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Ag{sub 1} (FCSNB-Ag) and Fe{sub 72}Cr{sub 6}Si{sub 4}Nb{sub 5}B{sub 12}Cu{sub 1} (FCSNB-Cu), prepared by using a melt-spinning technique. Magnetization (M) measurements for various temperatures (T) and magnetic fields (H) indicate that ferromagnetic-paramagnetic (FM-PM) phase transitions take place in FCSNB-Ag and FCSNB-Cu at Curie temperatures (T{sub C} ) of about 308.3 K and 322.5 K, respectively. Analyses of M - H data at different temperatures in the vicinity of the FM-PM phase transition based on the modified Arrott plot method and scaling hypothesis yielded the exponent values of β = 0.369 ± 0.005, γ = 1.359 ± 0.005 and δ = 4.7 ± 0.1 for FCSNB-Ag, and β = 0.376 ± 0.002, γ = 1.315 ± 0.006 and δ = 4.5 ± 0.1 for FCSNB-Cu. Compared with the values from theoretical models, these values are close to those expected for the 3D Heisenberg model, demonstrating the existence of short-range FM order in the amorphous alloy ribbons.

  14. Theory of singlet-ground-state magnetism. Application to field-induced transitions in CsFeCl3 and CsFeBr3

    DEFF Research Database (Denmark)

    Lindgård, P.-A.; Schmid, B.

    1993-01-01

    the experimental data can be excellently described by the self-consistent random-phase approximation results. For magnetic fields near the critical magnetic field only qualitative conclusions can be obtained. Numerical results for the critical scattering, the correlation lengths, and the specific heat, which....... A sophisticated numerical and graphical method leads to a self-consistent determination of the induced magnetization and the quadrupole moment as well as to the determination of the excitation spectrum for CsFeBr3 and CsFeCl3 as a function of the magnetic field. For magnetic fields below the phase transition...

  15. Probing structure-property relationships in perpendicularly magnetized Fe/Cu(001) using MXLD and XPD

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, T.R.; Waddill, G.D. [Univ. of Missouri, Rolla, MO (United States); Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Magnetic X-ray Linear Dichroism (MXLD) in Photoelectron Spectroscopy and X-Ray Photoelectron Diffraction (XPD) of the Fe 3p core level have been used to probe the magnetic structure-property relationships of perpendicularly magnetized Fe/Cu(001), in an element-specific fashion. A strong MEXLD effect was observed in the high resolution photoelectron spectroscopy of the Fe 3p at {open_quotes}normal{close_quotes} emission and was used to follow the loss of perpendicular ferromagnetic ordering as the temperature was raised toward room temperature. In parallel with this, {open_quotes}Forward Focussing{close_quotes} in XPD was used as a direct measure of geometric structure in the overlayer. These results and the implications of their correlation will be discussed. Additionally, an investigation of the effect of Mn doping of the Fe/Cu(001) will be described. These measurements were performed at the Spectromicroscopy Facility (Beamline 7.0.1) of the Advanced Light Source.

  16. Stability analysis of alkaline nitrobenzene-containing wastewater by a catalyzed Fe-Cu treatment process

    Institute of Scientific and Technical Information of China (English)

    FAN Jinhong; XU Wenying; GAO Tingyao; MA Luming

    2007-01-01

    Iron and copper bimetallic system (catalyzed Fe-Cu process) is a promising technology for alkaline nitrobenzene-containing wastewater treatment.However,little is currently known about the changes of treatment efficiency with time going.This research investigated the long-term performance of the catalyzed Fe-Cu process to reduce nitrobenzene (NB) in alkaline wastewater.In addition,the changes of the metal surfaces morphologies and matters before and after the reaction were analyzed by scanning electron microscopy (SEM) in conjunction with energydispersion spectroscopy (EDS) and X-ray diffraction spectroscopy (XRD).The results showed that the surface properties of copper almost remained unchanged after weeks of operation,which spelled its strong chemical stability and resistance to poisoning.Moreover,the results indicated that there were two reasons for the treatment efficiency decreasing with time.One was the gradual iron element consumption due to corrosion.The other was iron reactivity weakened due to the precipitates accumulation on the surfaces that were mainly Fe3O4 and FeCO.

  17. Investigation of Structure and Properties of Barrier Layers in Metals (Fe, Cu) at Low Temperatures

    Science.gov (United States)

    Kuterbekov, K. A.; Nurkenov, S. A.; Kislitsin, S. B.; Kuketayev, T. A.; Tussupbekova, A. K.

    2016-11-01

    Experimental studies of the effect of a barrier layer on the kinetics of thermally induced diffusion procesess and phase transformations in a layered Fe-Be syatem are investigated at the energy 1.6 MeV. Thermal stability of the barrier layer in the Fe:O+ system is validated and a possibility of its use as a subsurface layer for a beryllium coating is demonstrated. For the Cu:O+ system it is shown that the implanted layer in the matrix comes apart already at the annealing temperature 180°C and could not be used in a copper matrix as a subsurface barrier layer. For the first time, a method is proposed for retardation of diffusion and phase formation processes and realized in a layered iron - beryllium system using an implanted layer of oxygen ions. The sequence and characteristic times of thermally-induced phase-transformation processes taking place in the subsurface layers and in the bulk of the Fe (10 μm) systems: O+ - Be (0.7 μm) - 57Fe (0.1 μm) and Fe (10 μm) - Be (0.7 μm) - 57Fe (0.1 μm) are determined.

  18. Estudio cinético de las reacciones de recocido en aleaciones de Cu-Ni-Fe

    Directory of Open Access Journals (Sweden)

    Donoso, Eduardo

    2014-09-01

    Full Text Available The thermal aging of a Cu-45Ni-4Fe, Cu-34Ni-11Fe and Cu-33Ni-22Fe alloys tempered from 1173 K have been studied from Differential Scanning Calorimetry (DSC and microhardness measurements. The analysis of DSC curves, from room temperature to 950 K, shows the presence of one exothermic reaction associated to the formation of FeNi3 phase nucleating from a modulate structure, and one endothermic peak attributed to dissolution of this phase. Kinetic parameters were obtained using the usual Avrami-Erofeev equation, modified Kissinger method and integrated kinetic functions. Microhardness measurements confirmed the formation and dissolution of the FeNi3 phase.Mediante Calorimetría Diferencial de Barrido (DSC y medidas de microdureza Vickers se ha estudiado el comportamiento durante el recocido de las aleaciones Cu-45Ni-4Fe, Cu-34Ni-11Fe y Cu-33Ni-22Fe templadas desde 1173 K. El análisis de las curvas DSC, desde temperatura ambiente hasta los 950 K, muestran la presencia de una reacción exotérmica asociada a la formación de la fase FeNi3 que nuclea a partir de una estructura modulada, y una reacción endotérmica que correspondería a la disolución de esta fase. Los parámetros cinéticos se calcularon a partir de la ecuación usual de Avrami-Erofeev, Kissinger modificado y funciones cinéticas integradas. Medidas de microdureza Vickers corroboraron la formación y disolución de fase FeNi3.

  19. Effects of FeCo magnetic nanoparticles on microstructure of Sn-Ag-Cu alloys

    Science.gov (United States)

    Xu, Siyang; Habib, Ashfaque H.; Prasitthipayong, Anya; McHenry, Michael E.

    2013-05-01

    Sn-Ag-Cu (SAC) alloys have been regarded as the most promising candidates for lead-free solders in the electronic packaging industry. We prepared SAC solder-FeCo magnetic nanoparticles (MNPs) composite paste with different MNP concentration and used AC magnetic fields localized heating to cause their reflow. Differential scanning calorimetry results show a reduced undercooling of the composite paste with the addition of MNPs. Transmission electron microscope prove that the FeCo MNPs are distributed in Sn matrix of the reflowed solder composites. Optical micrographs show a decrease in the amount of primary Ag3Sn and β-Sn dendrites, and an increase in the amount of eutectic microconstituents with increasing MNPs. The addition of FeCo MNPs is considered to promote the solidification of β-Sn by providing more heterogeneous nucleation sites at a relatively low undercooling, which results in the microstructural refinement in the as-prepared solder joints.

  20. Rapid solidification and dendrite growth of ternary Fe-Sn-Ge and Cu-Pb-Ge monotectic alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The phase separation and dendrite growth characteristics of ternary Fe-43.9%Sn- 10%Ge and Cu-35.5%Pb-5%Ge monotectic alloys were studied systematically by the glass fluxing method under substantial undercooling conditions. The maximum undercoolings obtained in this work are 245 and 257 K, respectively, for these two alloys. All of the solidified samples exhibit serious macrosegregation, indicating that the homogenous alloy melt is separated into two liquid phases prior to rapid solidification. The solidification structures consist of four phases including α-Fe, (Sn), FeSn and FeSn2 in Fe-43.9%Sn-10%Ge ternary alloy, whereas only (Cu) and (Pb) solid solution phases in Cu-35.5%Pb-5%Ge alloy under different undercool- ings. In the process of rapid monotectic solidification, α-Fe and (Cu) phases grow in a dendritic mode, and the transition "dendrite→monotectic cell" happens when alloy undercoolings become sufficiently large. The dendrite growth velocities of α-Fe and (Cu) phases are found to increase with undercooling according to an exponential relation.

  1. Rapid solidification and dendrite growth of ternary Fe-Sn-Ge and Cu-Pb-Ge monotectic alloys

    Institute of Scientific and Technical Information of China (English)

    ZHANG XueHua; RUAN Ying; WANG WeiLi; WEI BingBo

    2007-01-01

    The phase separation and dendrite growth characteristics of ternary Fe-43.9%Sn- 10%Ge and Cu-35.5%Pb-5%Ge monotectic alloys were studied systematically by the glass fluxing method under substantial undercooling conditions. The maximum undercoolings obtained in this work are 245 and 257 K, respectively, for these two alloys. All of the solidified samples exhibit serious macrosegregation, indicating that the homogenous alloy melt is separated into two liquid phases prior to rapid solidification. The solidification structures consist of four phases including α-Fe, (Sn), FeSn and FeSn2 in Fe-43.9%Sn-10%Ge ternary alloy, whereas only (Cu) and (Pb) solid solution phases in Cu-35.5%Pb-5%Ge alloy under different undercoolings. In the process of rapid monotectic solidification, α-Fe and (Cu) phases grow in a dendritic mode, and the transition "dendrite→monotectic cell" happens when alloy undercoolings become sufficiently large. The dendrite growth velocities of α-Fe and (Cu) phases are found to increase with undercooling according to an exponential relation.

  2. Magnetic anisotropy and magneto optical property of Fe/Co/Cu(001): role of the interface alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dongyoo; Yang, Jeonghwa; Hong, Jisang [Pukyong National University, Busan (Korea, Republic of)

    2010-01-15

    Using the full potential linearized augmented plane wave (FLAPW) method, we have investigated the role of interface alloy type on the thickness dependent magnetic properties of ultrathin Fe/Co/Cu(001) films. We have observed that the Co underlayer induces an antiferromagnetic (AFM) state in Fe/Co/Cu(001) film, but the position of AFM layer is strongly sensitive to both Fe and Co coverage. It is found that the magnetic anisotropy of Fe/Co/Cu alloy films is significantly influenced by the alloy type and the Fe film thickness. For instance, a thickness-dependent spin reorientation transition from in-plane to perpendicular to the film surface or vice versa is observed in CoFe alloy configuration whereas the perpendicular magnetization is always achieved in CuCo alloy. In particular, a large perpendicular magnetic anisotropy energy (MAE) about 270 {mu}eV /atom at 4 ML Fe thickness is observed in the CuCo alloy. In addition, we find that the magnitude of Kerr rotation angle in the presence of antiferromagnetic layer is greatly suppressed compared with that of fully ferromagnetic films.

  3. Effect of Co and Ge addition on soft magnetic properties of Fe-Zr-B-Cu alloys

    Energy Technology Data Exchange (ETDEWEB)

    Blazquez, J.S. [Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany) and Departamento de Fisica de la Materia Condensada - ICMSE-CSIC, Universidad de Sevilla, P.O. Box 1065. 41080 Sevilla (Spain)]. E-mail: jsebas@us.es; Roth, S. [Leibniz Institute for Solid State and Materials Research Dresden, Helmholtzstrasse 20, 01069 Dresden (Germany); Conde, A. [Departamento de Fisica de la Materia Condensada. ICMSE-CSIC, Universidad de Sevilla, P.O. Box 1065. 41080 Sevilla (Spain)

    2005-04-15

    Microstructure and magnetic properties are studied for Fe{sub 78}Co{sub 5}Zr{sub 6}Ge{sub 5}B{sub 5}Cu{sub 1} alloy. Curie temperature of the amorphous phase is increased by 200 K with respect to Fe-Zr-B-Ge-Cu alloys, without losing the ultrasoft magnetic properties exhibited at room temperature (H {sub C}{approx}10 A/m). Nanocrystalline microstructure shows a high crystalline volume fraction of {alpha}-Fe nanocrystals ({approx}0.85) with size below 13 nm. Ge content in the crystalline phase is found to decrease continuously during nanocrystallization.

  4. Magnetic phase diagram of multiferroic delafossite CuFe{sub 1-y}Ga{sub y}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Terada, N; Kitazawa, H [National Institute for Materials Science, Tsukuba, Ibaraki, Japan 305-0047 (Japan); Nakajima, T; Mitsuda, S, E-mail: terada.noriki@nims.go.j [Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo 162-8601 (Japan)

    2009-01-01

    We report magnetic susceptibility measurements on nonmagnetic impurity-doped multiferroic CuFe{sub 1-y}Ga{sub y}O{sub 2} with 0 <= y <= 0:08. The temperature versus Ga concentration magnetic phase diagram was obtained. Comparing the presently obtained phase diagram of CuFe{sub 1-y}Ga{sub y}O{sub 2} with that of CuFe{sub 1-x}Al{sub x}O{sub 2}, we find that the stability of 4SL ground state for substitution of nonmagnetic ions does not depend on the nonmagnetic ionic radius significantly. On the other hand, the FEIC phase in CuFe{sub 1-y}Ga{sub y}O{sub 2} exists in a wider region of 0:02 <= y <= 0:05 than CuFe{sub 1-x}Al{sub x}O{sub 2}. We thus find that the local lattice distortion caused by large difference in ionic radii between Al3{sup +} and Fe3{sup +} affects the stability of the FEIC phase for nonmagnetic ion substitution significantly.

  5. Magnetic properties of CaCu5-type RNi3TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds

    Science.gov (United States)

    Morozkin, A. V.; Knotko, A. V.; Yapaskurt, V. O.; Yao, Jinlei; Yuan, Fang; Mozharivskyj, Y.; Nirmala, R.; Quezado, S.; Malik, S. K.

    2015-12-01

    Magnetic properties and magnetocaloric effect of CaCu5-type RNi3TSi (R=Gd and Tb, T=Mn, Fe, Co and Cu) compounds have been investigated. Magnetic measurements of RNi3TSi display the increasing of Curie temperature and the decreasing of magnetocaloric effect and saturated magnetic moment in the row of 'RNi3CuSi-RNi3NiSi-RNi3CoSi-RNi3MnSi-RNi3FeSi'. In contrast to GdNi3{Mn, Fe, Co}Si, TbNi3{Mn, Fe, Co}Si exhibit significant magnetic hysteresis. The coercive field increases from TbNi4Si ( 0.5 kOe) to TbNi3CoSi (4 kOe), TbNi3MnSi (13 kOe) and TbNi3FeSi (16 kOe) in field of 50 kOe at 5 K, whereas TbNi3CuSi exhibits a negligible coercive field.

  6. Distribution of Ca, Fe, Cu and Zn in primary colorectal cancer and secondary colorectal liver metastases

    Science.gov (United States)

    Al-Ebraheem, A.; Mersov, A.; Gurusamy, K.; Farquharson, M. J.

    2010-07-01

    A microbeam synchrotron X-ray fluorescence (μSRXRF) technique has been used to determine the localization and the relative concentrations of Zn, Cu, Fe and Ca in primary colorectal cancer and secondary colorectal liver metastases. 24 colon and 23 liver samples were examined, all of which were formalin fixed tissues arranged as microarrays of 1.0 mm diameter and 10 μm thickness. The distribution of these metals was compared with light transmission images of adjacent sections that were H and E stained to reveal the location of the cancer cells. Histological details were provided for each sample which enable concentrations of all elements in different tissue types to be compared. In the case of liver, significant differences have been found for all elements when comparing tumour, normal, necrotic, fibrotic, and blood vessel tissues (Kruskal Wallis Test, Pcolon samples (Kruskal Wallis Test, Pcolon tissues. Comparing liver tumour and colon tumour samples, significant differences have been found for all elements (Mann Whitney, Pcolon areas (independent T test, P=0.007 for Zn and Mann Whitney test P<0.0001 for Cu, Fe and Ca). For the blood vessel tissue, the analysis revealed that the difference was only significant for Fe ( P=0.009) from independent T test.

  7. Experimental investigation of inhomogeneities, nanoscopic phase separation, and magnetism in arc melted Fe-Cu metals with equal atomic ratio of the constituents

    KAUST Repository

    Hassnain Jaffari, G.

    2015-12-16

    Composition gradient and phase separation at the nanoscale have been investigated for arc-melted and solidified with equiatomic Fe-Cu. Diffraction studies revealed that Fe and Cu exhibited phase separation with no trace of any mixing. Microscopy studies revealed that immiscible Fe-Cu form dense bulk nanocomposite. The spatial distribution of Fe and Cu showed existence of two distinct regions, i.e., Fe-rich and Cu-rich regions. Fe-rich regions have Cu precipitates of various sizes and different shapes, with Fe forming meshes or channels greater than 100 nm in size. On the other hand, the matrix of Cu-rich regions formed strips with fine strands of nanosized Fe. Macromagnetic response of the system showed ferromagnetic behavior with a magnetic moment being equal to about 2.13 μB/Fe atom and a bulk like negligible value of coercivity over the temperature range of 5–300 K. Anisotropy constant has been calculated from various laws of approach to saturation, and its value is extracted to be equal to 1350 J/m3. Inhomogeneous strain within the Cu and Fe crystallites has been calculated for the (unannealed) sample solidified after arc-melting. Annealed sample also exhibited local inhomogeneity with removal of inhomogeneous strain and no appreciable change in magnetic character. However, for the annealed sample phase separated Fe exhibited homogenous strain.

  8. Electrical conductivity of Cu/(10NiO-NiFe2O4) cermet inert anode for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cu/(10NiO-NiFe2O4) cermets containing mass fractions of Cu of 5%, 10%, 15% and 20% were prepared, and their electrical conductivities were measured at different temperatures. The effects of temperature and content of metal Cu on the electrical conductivity were investigated especially. The results indicate that the metallic phase Cu distributes evenly in 10NiO-NiFe2O4 ceramic matrix. The mechanism of electrical conductivity of Cu/(10NiO-NiFe2O4) cermets obeys the rule of electrical mechanism of semiconductor, the electrical conductivity for cermet containing 5% Cu increases from 2.70 to 20.41 S/cm with temperature increasing from 200 to 900 ℃. The change trend of electrical conductivity with temperature is similar with each other and it increases with increasing temperature and content of metal Cu. At 960 ℃, the electrical conductivity of cermet increases from 2.88 to 82.65 S/cm with the content of metal Cu increasing from 0 to 20%.

  9. Crystal structure of CuFe{sub 2}InSe{sub 4} from X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, G.E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)], E-mail: gerzon@ula.ve; Mora, A.J. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, P.; Quintero, M. [Centro de Estudio de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2008-04-24

    The crystal structure of the semiconductor compound CuFe{sub 2}InSe{sub 4} was analyzed using X-ray powder diffraction data. The powder pattern refined by the Rietveld method was composed of 86.6% of the principal phase CuFe{sub 2}InSe{sub 4} and 13.4% of the binary phase FeSe. CuFe{sub 2}InSe{sub 4} crystallizes in the tetragonal space group I4-bar2m (no. 121), Z = 2, with unit cell parameters a = 5.7694(3) A, c = 11.495(1) A, V = 382.62(4) A{sup 3}. FeSe crystallizes in the tetragonal space group P4/nmm (no. 129), Z = 2, and a = 3.784(1) A, c 5.502(2) A, V = 78.78(4) A{sup 3}. The refinement of 28 instrumental and structural parameters led to R{sub p} = 8.2%, R{sub wp} = 10.7%, R{sub exp} = 6.7% and S = 1.7; R{sub B} = 9.9% (CuFe{sub 2}InSe{sub 4}), R{sub B} = 8.8% (FeSe) for 76 and 36 independent reflections, respectively.

  10. Room temperature deposition of amorphous p-type CuFeO$_2$ and fabrication of CuFeO$_2$/n-Si heterojunction by RF sputtering method

    Indian Academy of Sciences (India)

    TAO ZHU; ZANHONG DENG; XIAODONG FANG; WEIWEI DONG; JINGZHEN SHAO; RUHUA TAO; SHIMAO WANG

    2016-06-01

    Transparent conducting amorphous p-type CuFeO$_2$ (CFO) thin film was prepared by radio-frequency (RF) magnetron sputtering method at room temperature using polycrystalline CuFeO$_2$ target. Amorphous structureof as-deposited film was confirmed by XRD. XPS analysis convinced that the chemical state of Cu$^{+}$ and Fe$^{3+}$ in the film, and the chemical composition of the thin films is close to the stoichiometry of CuFeO$^2$. Surface morphology of the film was analysed by SEM studies. p-type nature and concentration of carriers was investigated by Hall effect measurement. The p–n heterojunction in the structure of Al/n-Si/p-CuFeO$_2$/Al showed good rectifying behaviour with a forward and reverse currents ratio of 555 at 2 V. The turn-on voltage and reverse leakage current values were found to be 0.9 V and 4 $\\mu$A at $−$2 V. Further, the conduction mechanism of forward bias voltage was controlled by thermionic emission (TE) and trap-space charge limited current (TCLC) mechanisms.

  11. Epitaxial Cu(001) films grown on a Cr/Ag/Fe/GaAs(001) buffer system

    Energy Technology Data Exchange (ETDEWEB)

    Gottlob, Daniel M., E-mail: d.gottlob@fz-juelich.de [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Fakultät für Physik and Center for Nanointegration Duisburg-Essen (CeNIDE), Universität Duisburg-Essen, 47048 Duisburg (Germany); Jansen, Thomas [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Jülich-Aachen Research Alliance, Fundamentals for Future Information Technology (JARA-FIT), Forschungszentrum Jülich, 52425 Jülich (Germany); Hoppe, Michael [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Bürgler, Daniel E. [Peter Grünberg Institut, Electronic Properties (PGI-6), Forschungszentrum Jülich, 52425 Jülich (Germany); Jülich-Aachen Research Alliance, Fundamentals for Future Information Technology (JARA-FIT), Forschungszentrum Jülich, 52425 Jülich (Germany); and others

    2014-07-01

    We present a procedure to prepare single-crystalline, high-purity Cu(001) films (templates) suitable as substrates for subsequent epitaxial thin-film growth. The template films were grown in a dedicated molecular-beam epitaxy system on a Cr/Ag/Fe/GaAs(001) buffer layer system. Low-energy electron diffraction and X-ray diffraction were applied to determine the surface orientation and the epitaxial relationship between all layers of the stack. Post-annealing at moderate temperatures enhances the quality of the film as shown by low-energy electron diffraction and atomic force microscopy. X-ray photoemission and Auger electron spectroscopy confirm that no atoms of the buffer layers diffuse into the Cu film during the initial preparation and the post-annealing treatment. The completed Cu(001) template system can be exposed to air and afterwards refurbished by Ar{sup +}-ion bombardment and annealing, enabling the transfer between vacuum systems. The procedure provides suitable conductive thin film templates for studies of epitaxial thin films, e.g. on the magnetic and magnetotransport properties of Co and Ni based films and multilayers. - Highlights: • Preparation of epitaxial Cu(001) template films on an insulating substrate • Characterization of template structure, orientation, cleanness, and roughness • Template films can be exposed to air and refurbished in different vacuum system. • Template films are suitable for further thin film growth at up to 570 K.

  12. Reinforcement of bulk Y-Ba-Cu-O superconductors by using Fe-Mn-Si-Ni shape memory alloy rings

    Science.gov (United States)

    Seki, H.; Honma, Y.; Nomura, M.; Nakayama, C.; Koshizuka, N.; Maruyama, T.; Murakami, M.

    Bulk Y-Ba-Cu-O superconductors are brittle ceramics and their tensional strengths are very low. Therefore, reinforcement of the bulk superconductor is needed for practical applications. Pre-compression load has been shown to be effective in enforcing the bulk superconductors. Fe-Mn-Si alloys exhibit shape-memory effects and the size change due to the shape recovery is large. Therefore, the Fe-Mn-Si shape memory alloy rings will function as effective reinforcement material for the bulk superconductors. We prepared Y-Ba-Cu-O bulk superconductors with top-seeded melt-growth process and the Ni added Fe-Mn-Si (Fe-Mn-Si-Ni) alloy ring which exhibited better shape memory performances than Ni-free Fe-Mn-Si alloys. The ring was extended by inserting a steel rod and heated to 623K. The amount of shape recovery strain was about 2%. Based on these results, the TSMG-processed bulk YBa- Cu-O superconductor 39.0 mm in diameter was inserted into the Fe-Mn-Si-Ni ring whose inner diameter was 39.3 mm at room temperature. With heating to 623K, the Fe-Mn-Si-Ni ring shrank and firmly encapsulated the bulk Y-Ba-Cu-O superconductor. Cracking was not observed in the bulk superconductor. It was interesting to note that the trapped magnetic field of the Y-Ba-Cu-O superconductor at 77K was increased from 2,550 G to 3,795 G through Fe-Mn-Si-Ni ring reinforcement. These results clearly show that the reinforcement treatment with Fe-Mn-Si-Ni alloy ring or pre-compression load is effective in improving the field trapping ability in addition to thee improvement of the mechanical properties.

  13. The CU ground MAX-DOAS instrument: characterization of RMS noise limitations and first measurements near Pensacola, FL of BrO, IO, and CHOCHO

    Science.gov (United States)

    Coburn, S.; Dix, B.; Sinreich, R.; Volkamer, R.

    2011-11-01

    We designed and assembled the University of Colorado Ground Multi AXis Differential Optical Absorption Spectroscopy (CU GMAX-DOAS) instrument to retrieve bromine oxide (BrO), iodine oxide (IO), formaldehyde (HCHO), glyoxal (CHOCHO), nitrogen dioxide (NO2) and the oxygen dimer (O4) in the coastal atmosphere of the Gulf of Mexico. The detection sensitivity of DOAS measurements is proportional to the root mean square (RMS) of the residual spectrum that remains after all absorbers have been subtracted. Here we describe the CU GMAX-DOAS instrument and demonstrate that the hardware is capable of attaining RMS of ∼6 × 10-6 from solar stray light noise tests using high photon count spectra (compatible within a factor of two with photon shot noise). Laboratory tests revealed two critical instrument properties that, in practice, can limit the RMS: (1) detector non-linearity noise, RMSNLin, and (2) temperature fluctuations that cause variations in optical resolution (full width at half the maximum, FWHM, of atomic emission lines) and give rise to optical resolution noise, RMSFWHM. The non-linearity of our detector is low (∼10-2) yet - unless actively controlled - is sufficiently large to create RMSNLin of up to 2 × 10-4. The optical resolution is sensitive to temperature changes (0.03 detector pixels °C-1 at 334 nm), and temperature variations of 0.1°C can cause RMSFWHM of ~1 × 10-4. Both factors were actively addressed in the design of the CU GMAX-DOAS instrument. With an integration time of 60 s the instrument can reach RMS noise of 3 × 10-5, and typical RMS in field measurements ranged from 6 × 10-5 to 1.4 × 10-4. The CU GMAX-DOAS was set up at a coastal site near Pensacola, Florida, where we detected BrO, IO and CHOCHO in the marine boundary layer (MBL), with daytime average tropospheric vertical column densities (average of data above the detection limit), VCDs, of ∼2 × 1013 molec cm-2, 8 × 1012 molec cm-2 and 4 × 1014 molec cm-2, respectively. HCHO and

  14. Comparative TPR and TPD Studies of Cu and Ca Promotion on Fe-Zn- and Fe-Zn-Zr-Based Fischer-Tropsch Catalysts

    Directory of Open Access Journals (Sweden)

    James Olusola O.

    2015-03-01

    Full Text Available The present study demonstrates the effect of zirconium promotion on Fe-Zn-based catalysts to boost the active sites of Fischer-Tropsch (FT catalysts. The catalysts are also promoted by Cu and Ca and the active sites are examined using Temperature-Programmed Reduction (TPR with H2 and CO and Temperature-Programmed Desorption (TPD with NH3 and CO2. The results are presented as a comparative study between Fe-Zn- and Fe-Zn-Zr-based catalysts. The results show that addition of Zr to Fe-Zn catalysts increases the availability and dispersion of the precursor to the active sites and promotion with Cu and Ca independently and synergistically enhances reduction of Fe-Zn-Zr-based catalysts. The presence of Ca promotes carburisation, while Cu inhibits carburisation. The impact of the Ca and Cu on the surface acidity/basicity is governed by the nature of the interaction between the phases in the catalysts. The extent of reduction reflects the availability and dispersion of the precursor to the active phase, while the extent of carburisation will impact on the selectivity of the catalysts.

  15. Oxidation of Refractory Benzothiazoles with PMS/CuFe2O4: Kinetics and Transformation Intermediates

    KAUST Repository

    Zhang, Tao

    2016-05-04

    Benzothiazole (BTH) and its derivatives, 2-(methylthio)bezothiazole (MTBT), 2-benzothiazolsulfonate (BTSA) and 2-hydroxybenzothiazole (OHBT), are refractory pollutants ubiquitously existing in urban runoff at relatively high concentrations. Here, we report their oxidation by CuFe2O4-activated peroxomonosulfate (PMS/CuFe2O4), focusing on kinetics and transformation intermediates. These benzothiazoles can be efficiently degraded by this oxidation process which is confirmed to generate mainly sulfate radicals (with negligible hydroxyl-radical formation) under slightly acidic to neutral pH conditions. The molar exposure ratio of sulfate radical to residual PMS (i.e. Rct) of this process is a constant which is related to reaction condition and can be easily determined. Reaction rate constants of these benzothiazoles towards sulfate radical are (3.3 ± 0.3) × 109, (1.4 ± 0.3) × 109, (1.5 ± 0.1) × 109 and (4.7 ± 0.5) × 109 M-1s-1, respectively (pH 7 and 20 oC). Based on Rct and these rate constants, their degradation in the presence of organic matter can be well predicted. A number of transformation products were detected and tentatively identified using triple-quadruple/linear ion trap MS/MS and high-resolution MS. It appears that sulfate radicals attack BTH, MTBT and BTSA on their benzo ring via electron transfer, generating multiple hydroxylated intermediates which are reactive towards common oxidants. For OHBT oxidation, it prefers to break down the thiazole ring. Due to competitions of the transformation intermediates, a minimum PMS/pollutant molar ratio of 10-20 is required for effective degradation. The flexible PMS/CuFe2O4 could be a useful process to remove the benzothiazoles from low DOC waters like urban runoff or polluted groundwater.

  16. The Effect of Substitution of Fe By Co on Rapidly Quenched (FeCoMoCuB Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Clara F. Conde

    2005-01-01

    Full Text Available (Fe1-xCox79Mo8Cu1B15 amorphous alloys ware prepared in the form of ribbons by rapid quenching for x=0. 0.25 and 0.5. The effect of variation of Co/Fe ratio is analyzed with respect to the formation of amorphous state and to transformation of the structure into nancrystalline phases formed after subsequent thermal treatment. Selected properties and atomic structure in as-quenched state are studied by TEM, AFM, XRD any by measurement of magnetoresistance characteristics. The influence of heat treatment on transport and magnetic properties is shown on temperature dependencies of electrical resistivity and magnetization. It was founf that while the increase of Co content leads to the increase of Curie temperature of as-quenched structure, transition to nanocrystalline state is not affected in a significant manner. The as-quenched state for alloy without Co was found to contain thin crystal-containing layer which, however, was observed, contary to general behavior, at the side of the ribbon exposed to higher quenching rates.

  17. Anisotropic Magnetoresistance Effect in Amorphous and Nanocrystalline Fe(Cu,Nb)-Si-B Alloys

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The magnetoresistance effect and magnetic properties in amorphous and nanocrystalline Fe(Cu, Nb)-Si-B ribbons have been investigated. It was observed that the anisotropic magnetoresistance (AMR) of nanocrystalline alloy is much smaller than that of amorphous alloy, indicating that the anisotropy of nanocrystalline alloy becomes smaller after crystallizing, and the smallest AMR is coincident with the excellent soft magnetic characteristics. It is believed that the smaller magnetic crystalline anisotropy is the origin of the excellent soft magnetic characteristics of nanocrystalline alloy.

  18. Some aspects of thermally induced martensite in Fe-30% Ni-5% Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Guener, M. [Department of Physics, Faculty of Science and Arts, University of Kirikkale, 71450 Yahsihan, Kirikkale (Turkey)]. E-mail: martensite@email.com; Gueler, E. [Department of Physics, Faculty of Science and Arts, University of Hitit, 19030, Corum (Turkey); Yasar, E. [Department of Physics, Faculty of Science and Arts, University of Kirikkale, 71450 Yahsihan, Kirikkale (Turkey); Aktas, H. [Department of Physics, Faculty of Science and Arts, University of Kirikkale, 71450 Yahsihan, Kirikkale (Turkey)

    2007-05-31

    Kinetical, morphological, crystallographical and several thermal properties of thermally induced martensite in the austenite phase of Fe-30% Ni-5% Cu alloy were investigated. Scanning electron microscope (SEM), transmission electron microscope (TEM) and differential scanning calorimetry (DSC) techniques were used during study. Kinetics of the transformation was found to be as athermal type. SEM and TEM observations revealed {alpha}' (BCC) martensite formation in the austenite phase of alloy by thermal effect. These thermally induced {alpha}' martensites exhibited a thin plate-like morphology with twinnings.

  19. Kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with inert gases

    Directory of Open Access Journals (Sweden)

    B. Oleksiak

    2011-04-01

    Full Text Available Discussion of the kinetics of lead removal from the Cu-Pb-Fe alloy by barbotage with argon and helium. The values of the mass penetration coefficient for the liquid and solid phase as well as the mass transfer coefficient were calculated for the temperatures of 1 473 K and 1 548 K, and for the gas flow rate of 5,55 • 10-6, 6,94 • 10-6, 8,33 • 10-6 and 9,72 • 10-6 m • s-1.

  20. Cu, Mn, Fe, and Zn Levels in Soils of Shika Area, Nigeria

    Institute of Scientific and Technical Information of China (English)

    S. A. MASHI; S. A. YARO; A. S. HAIBA

    2004-01-01

    Heavy metals presented in toxic amounts can become injurious to human health. In areas where there is a high level of human activities on soils (such as agriculture and grazing) studies are therefore required from time to time to monitor levels of such metals in the soils in order to identify the point in time when toxicity problems become real. The 英文摘要: of this paper is to determine the concentrations of some trace metals (Cu, Mn, Fe, and Zn) in soils under cultivation and grazing practices in Shika, a rural area of Kaduna state of Nigeria. Method In this study, soil samples collected from three different categories of locations (cultivated, grazed, and uncultivated/non- grazed serving as a control) across Shika area, Nigeria, were analysed for some trace metal levels (Cu, Mn, Fe, and Zn) using atomic absorption spectrophotometry. For each category, multiple sites were chosen to accommodate all possible intra-category variations, especially in terms of land use and management history and topographic characteristics. Topsoil (0-15 cm) and subsoil (20-30 cm) samples were collected from every site and analysed for the above metals. Averaged values of the metals for the three categories revealed that Zn is the most abundant metal, followed by Fe, then Mn and Cu the least. Results The results obtained indicate that the cultivation practices, and to a lesser extent grazing, in the area result in higher levels of all the metals than in the control, suggesting that crop immobilization of the metals from soils of the area is low, and that their systematic accumulation is taking place in cultivated soils of the area. Prospects of having elevated soil levels of the metals due to cultivation practices in the area therefore seem quite high. Conclusion On the basis of the results obtained, it was concluded that grazing and cultivation practices have in general caused some significant elevations in the bioavailable (i.e the plant available forms) levels of Zn, Fe, Mn

  1. An investigation on microwave sintering of Fe, Fe–Cu and Fe–Cu–C alloys

    Indian Academy of Sciences (India)

    Raja Annamalai; Anish Upadhyaya; Dinesh Agrawal

    2013-06-01

    The powder characteristics of metallic powders play a key role during sintering. Densification and mechanical properties were also influenced by it. The current study examines the effect of heating mode on densification, microstructure, phase compositions and properties of Fe, Fe–2Cu and Fe–2Cu–0.8C systems. The compacts were heated in 2.45 GHz microwave sintering furnaces under forming gas (95%N2–5%H2) at 1120 °C for 60 min. Results of densification, mechanical properties and microstructural development of the microwave-sintered samples were reported and critically analysed in terms of various powder processing steps.

  2. Physical, mechanical, and tribological properties of quasicrystalline Al-Cu-Fe coatings prepared by plasma spraying

    Science.gov (United States)

    Lepeshev, A. A.; Rozhkova, E. A.; Karpov, I. V.; Ushakov, A. V.; Fedorov, L. Yu.

    2013-12-01

    The physical, mechanical, and tribological properties of quasicrystalline coatings based on the Al65Cu23Fe12 alloy prepared by plasma spraying have been investigated. The specific features of the phase formation due to the competitive interactions of the icosahedral ψ and cubic β phases have been elucidated. A correlation between the microhardness and the content of the icosahedral phase in the coating has been determined. The decisive role of the quasicrystalline phase in the formation of high tribological characteristics of the coatings has been revealed and tested.

  3. Characterization of pillared clays containing Fe{sup 3+} and Cu

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Vidal, H.; Custodio-Garcia, E.; Morales-Hidalgo, J. [Division Academica de Ciencias Basicas, Universidad Juarez Autonoma de Tabasco, Km 1.5 Carretera Cunduacan-Jalpa, CP. 86690, Cunduacan, Tabasco (Mexico); Lopez-Alejandro, E.; Frias-Marquez, D.M. [Division Academica de Ingenieria y Arquitectura, Universidad Juarez Autonoma de Tabasco, Km 1.5 Carretera Cunduacan-Jalpa, CP. 86690, Cunduacan, Tabasco (Mexico)

    2006-04-14

    We report the synthesis of pillared clays from natural Mexican bentonites and pillared solutions as a support for Cu and Fe{sup 3+} catalyst. The study shows a favorable cationic exchange capacity on the clays. This is observed with a change of the specific areas: from 66m{sup 2}/g for the natural clay to 202m{sup 2}/g for the pillared clay. The molar relation of 4.91 for the Si/Al structure in the natural clay and 3.72 for the pillared clay shows the entrance of aluminum as pillaring ion. We were able to increase the microporosity on the catalytic material observed through a porous volume variation (0.1-0.8cm{sup 3}/g) at different Fe{sup 3+} concentrations. We obtained an increase on the specific area of more than 200% over the natural clay. (author)

  4. Mechanical alloying in Fe2O3-MO (M: Zn, Ni, Cu, Mg) systems

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gerward, Leif; Mørup, Steen

    1999-01-01

    of MFe2O4 ferrites are critically discussed. No significant with respect to ferrite formation rates was observed in open and closed containers used here. In the Fe2O3/ZnO system, a single ferrite phase can be synthesized but in other systems no significant amounts of ferrites are formed by high......Mechanical alloying processes in four Fe2O3MO (M: Zn, Ni, Cu, Mg) systems by high-energy ball milling from simple oxide powder mixtures in both open and closed tungsten carbide containers have been investigated by x-ray powder diffraction and Mossbauer spectroscopy. Mechanisms for the formation......-energy ball milling under the conditions used here. The dominant alloying mechanism depends on the interdiffusion at relatively low temperatures. The experimental results may also be explained by the crystal structures of the reactants and the ferrites....

  5. Effects of surface crystallization and oxidation in nanocrystalline FeNbCuSiB(P) ribbons

    Science.gov (United States)

    Butvinová, B.; Butvin, P.; Brzózka, K.; Kuzminski, M.; Maťko, I.; Švec, P., Sr.; Chromčíková, M.

    2017-02-01

    Si-poor Fe74Nb3Cu1Si8B14-xPx, (x=0, 3) nanocrystalline ribbon-form alloys often form surfaces, which exert in-plane force on underlying ribbon interior when nanocrystallized in even modest presence of oxygen. Mostly unwanted hard-ribbon-axis magnetic anisotropy is standard result. Essential sources of the surface-caused stress have been sought and influence of P instead of B substitution on this effect was studied too. Preferred surface crystallization (PSC) was found to be the major reason. However P substitution suppresses PSC and promotes Fe-oxide formation, which eases the stress, softens the surfaces and provides different annealing evolution of surface properties.

  6. Magnetic properties of (Zn,Cd,Cu) Co Fe Ti spinel oxides

    Science.gov (United States)

    Moyo, T.; Giordanengo, B.; de Melo, M. A. C.; Takeuchi, A. Y.; Silva, P. R. J.; Saitovitch, H.; Baggio-Saitovitch, E.

    1999-09-01

    AC susceptibility, magnetization and Mössbauer spectra have been measured for (Zn,Cd,Cu)0.5Co0.9Fe1.2Ti0.4O4 and Zn0.3Co0.9Fe1.4Ti0.4O4 spinel oxides. The variation of coercive field below the spin glass transition temperature Tsg is found to fit a double exponential function of the form H_c left( T right) = H_{1e} ^{ - β _1 T} + H_{2e} ^{ - β _2 T} , where Hi and βi are constants. Mössbauer spectra and analysis show superparamagnetic fluctuations associated with magnetic clusters. Symmetric doublets above Tsg are decomposed into quadrupole doublets associated with tetrahedral (A) and octahedral (B) sites.

  7. Induced Ferromagnetism at BiFeO3/YBa2Cu3O7 Interfaces

    Science.gov (United States)

    Zhu, Jian-Xin; Wen, Xiao-Dong; Haraldsen, J. T.; He, Mi; Panagopoulos, C.; Chia, Elbert E. M.

    2014-06-01

    Transition metal oxides (TMOs) exhibit many emergent phenomena ranging from high-temperature superconductivity and giant magnetoresistance to magnetism and ferroelectricity. In addition, when TMOs are interfaced with each other, new functionalities can arise, which are absent in individual components. Here, we report results from first-principles calculations on the magnetism at the BiFeO3/YBa2Cu3O7 interfaces. By comparing the total energy for various magnetic spin configurations inside BiFeO3, we are able to show that a metallic ferromagnetism is induced near the interface. We further develop an interface exchange-coupling model and place the extracted exchange coupling interaction strengths, from the first-principles calculations, into a resultant generic phase diagram. Our conclusion of interfacial ferromagnetism is confirmed by the presence of a hysteresis loop in field-dependent magnetization data. The emergence of interfacial ferromagnetism should have implications to electronic and transport properties.

  8. Formation dynamics of FeN thin films on Cu(100)

    KAUST Repository

    Heryadi, Dodi

    2012-01-01

    To investigate the structural and magnetic properties of thin films of FeN we have performed ab initio molecular dynamics simulations of their formation on Cu(100) substrates. The iron nitride layers exhibit a p4gm(2 × 2) reconstruction and order ferromagnetically in agreement with experiment. We establish the dynamics and time scale of the film formation as a function of the film thickness. The process is split in two phases: formation of almost flat FeN layers and optimization of the distance to the substrate. Our calculated magnetic moments are 1.67 μ B, 2.14 μ B, and 2.21 μ B for one, two, and three monolayers of iron nitride. © 2011 Elsevier B.V. All rights reserved.

  9. Study on the Growth and Photorefractive Properties of In:Fe:Cu:LiNbO3 Crystals

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fe(0.2 mol%):Cu(0.04 mol%):LiNbO3 crystals with different doping concentration of In3+ (0, 1.0, 2.0, 3.0mol%) were grown by Czochralski method, and then oxidized and reduced. The infrared transmittance spectra of crystals were measured to investigate the location of doping ion and its threshold concentration. The photorefractive properties of the crystals were tested by two beam coupling experiment. The results showed that the threshold concentration of In ions is 2.0~3.0 mol% and In ions take the place of NbLi4+ to form (InLi2+) before reaching its threshold concentration, and then the location of normal Mb ions. In the (2.0 mol%):Fe:Cu:LiNbO3 crystal with the oxidation treatment having the highest diffraction efficiency (η = 45.8%), the photo-damage resistance threshold value R of In(3.0 mol%):Fe:Cu:LiNbO3 was 3.67×104 W/cm2 which was two orders of magnitude higher than that of Fe:Cu:LiNbO3 crystal (4.30×102 W/cm2). And the photo-damage resistance ability was enhanced by oxidized treatment. The In(2.0~3.0 mol%):Fe:Cu:LiNbO3 crystals with oxidized treatment have the best photorefractive properties.

  10. Investigation of optical and structural properties of Fe, Cu co-doped SnO2 nanoparticles

    Science.gov (United States)

    Nilavazhagan, S.; Muthukumaran, S.

    2015-07-01

    The undoped Sn0.98Fe0.02O2 and Cu-doped Sn0.98Fe0.02O2 nanoparticles have been synthesized by a simple chemical co-precipitation method. Structural and optical properties of the synthesized samples have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible spectrophotometer and photoluminescence (PL) spectroscopy. The tetragonal rutile structure was confirmed by XRD with no other phases observed. The crystallite size of the nanoparticles calculated from the XRD peaks was in the nanometer range (5-6 nm) which is in good agreement with the transmission electron microscopy (TEM) results. Substitution of Cu into the Sn0.98Fe0.02O2 nanoparticles can be confirmed by the shifting of peaks in XRD patterns. Sudden decrease in crystallite size at Cu = 6% doped sample could have resulted in blue shift in energy gap which revealed the domination of quantum confinement effect. The shift of lattice mode around 637-693 cm-1 and the change in shape of the band confirmed the presence of Cu in Sn-Fe-O. A strong violet peak around 391 nm and a weak blue photoluminescence peak around 459 nm were observed, while a blue peak appeared only after introducing Cu into the Fe-SnO2 host.

  11. Electrospun CuFe2O4 nanotubes as anodes for high-performance lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Shengjie Peng; Linlin Li; Madhavi Srinivasan

    2014-01-01

    Herein, we report on the synthesis and lithium storage properties of electrospun one-dimensional (1D) CuFe2O4 nanomaterials. 1D CuFe2O4 nanotubes and nanorods were fabricated by a single spinneret electrospinning method followed by thermal decomposition for removal of polymers from the precursor fibers. The as-prepared CuFe2O4 nanotubes with wall thickness of∼50 nm presented diameters of∼150 nm and lengths up to several millimeters. It was found that phase separation between the electrospun composite materials occured during the electrospinning process, while the as-spun precursor nanofibers composed of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP) and metal salts might possess a core-shell structure (PAN as the core and PVP/metal salts composite as the shell) and then transformed to a hollow structure after calcination. Moreover, as a demonstration of the functional properties of the 1D nanostructure, CuFe2 O4 nanotubes and nanorods were investigated as anodes for lithium ion batteries (LIBs). It was demonstrated that CuFe2O4 nanotubes not only delivered a high reversible capacity of ∼816 mAh·g-1 at a current density of 200 mA·g-1 over 50 cycles, but also showed superior rate capability with respect to counterpart nanorods. Probably, the enhanced electrochemical performance can be attributed to its high specific surface areas as well as the unique hollow structure.

  12. Meso-macroporous Fe-doped Cu O: Synthesis, characterization, and structurally enhanced adsorption and visible-light photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    朱剑飞; 肖奇

    2015-01-01

    The meso-macroporous Fe-doped Cu O was prepared by a simple hydrothermal method combined with post-annealing. The samples were characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), Brunauer-Emmett-Teller N2 adsorption-desorption analyses and UV-vis diffuses reflectance spectroscopy. The Fe-doped Cu O sample shows higher adsorption capacity and photocatalytic activity for xanthate degradation than pure Cu O under visible light irradiation. In addition, the adsorption process is found to fit Langmuir isotherms and pseudo-second-order kinetics. The the first order kinetic Langmuir Hinshelwood model was used to study the reaction kinetics of photocatalytic degradation, and the apparent rate constant( k) was calculated. The value of k for Fe-doped Cu O is 1.5 times that of pure Cu O. The higher photocatalytic activity of Fe-doped Cu O is attributed to higher specific surface area together with stronger visible light absorption.

  13. Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

    Directory of Open Access Journals (Sweden)

    Muad Saleh

    2016-05-01

    Full Text Available Magnetic Barkhausen noise (MBN, hysteresis measurements, first order reversal curves (FORC, Vickers microhardness, and Transmission Electron Microscopy (TEM analyses were performed on Fe-1wt.%Cu (Fe-Cu samples isothermally aged at 700°C for 0.5 – 25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEM measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850°C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures.

  14. Effects of aging time and temperature of Fe-1wt.%Cu on magnetic Barkhausen noise and FORC

    Science.gov (United States)

    Saleh, Muad; Cao, Yue; Edwards, Danny J.; Ramuhalli, Pradeep; Johnson, Bradley R.; McCloy, John S.

    2016-05-01

    Magnetic Barkhausen noise (MBN), hysteresis measurements, first order reversal curves (FORC), Vickers microhardness, and Transmission Electron Microscopy (TEM) analyses were performed on Fe-1wt.%Cu (Fe-Cu) samples isothermally aged at 700°C for 0.5 - 25 hours to obtain samples with different sized Cu precipitates and dislocation structures. Fe-Cu is used to simulate the thermal and irradiation-induced defects in copper-containing nuclear reactor materials such as cooling system pipes and pressure vessel materials. The sample series showed an initial increase followed by a decrease in hardness and coercivity with aging time, which is explained by Cu precipitates formation and growth as observed by TEM measurements. Further, the MBN envelope showed a continuous decrease in its magnitude and the appearance of a second peak with aging. Also, FORC diagrams showed multiple peaks whose intensity and location changed for different aging time. The changes in FORC diagrams are attributed to combined changes of the magnetic behavior due to Cu precipitate characteristics and dislocation structure. A second series of samples aged at 850°C, which is above the solid solution temperature of Fe-Cu, was studied to isolate the effects of dislocations. These samples showed a continuous decrease in MBN amplitude with aging time although the coercivity and hardness did not change significantly. The decrease of MBN amplitude and the appearance of the second MBN envelope peak are attributed to the changes in dislocation density and structure. This study shows that the effect of dislocations on MBN and FORC of Fe-Cu materials can vary significantly and should be considered in interpreting magnetic signatures.

  15. Magnetic analysis of a melt-spun Fe-dilute Cu{sub 60}Ag{sub 35}Fe{sub 5} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kondo, Shin-ichiro, E-mail: kondou@nagasaki-u.ac.jp [Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan); Kaneko, Kazuhiro; Morimura, Takao; Nakashima, Hiromichi [Faculty of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan); Kobayashi, Shin-Taro; Michioka, Chishiro; Yoshimura, Kazuyoshi [Department of Chemistry, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2015-04-15

    The magnetic properties of a melt-spun Fe-dilute Cu{sub 60}Ag{sub 35}Fe{sub 5} alloy are examined by X-ray diffraction, magnetic measurements, and transmission electron microscopy (TEM). The X-ray diffraction patterns show that the as-spun and annealed (773 K×36 ks) samples contain Cu and Ag phases and no Fe phases; thus, most Fe atoms are dispersed as clusters. Magnetic measurements indicate that the as-spun and annealed samples exhibit superparamagnetic behavior at 300 K, whereas ferromagnetic and superparamagnetic behaviors coexist at 4.2 K. The magnetic moments of small clusters at 300 K are determined by the nonlinear least squares method as 5148 and 4671 μ{sub B} for as-spun and annealed samples, respectively, whereas those at 300 K are experimentally determined as 3500 and 3200 μ{sub B}. This decrease in magnetic moments may imply the formation of anti-ferromagnetic coupling by annealing. TEM observation of the melt-spun sample suggests that there are three regions with different compositions: Cu-rich, Ag-rich, and Fe-rich with no precipitation in the matrix. In addition, these regions have obscure interfaces. The magnetic clusters are attributed to the Fe-rich regions.

  16. S, Zn, Cr, Cu and Fe changes during fluvial sediments oxidation Transformaciones del S, Zn, Cr, Cu y Fe en sedimentos fluviales durante el proceso de secado

    Directory of Open Access Journals (Sweden)

    María Pía Di Nanno

    2009-12-01

    Full Text Available Acidification of dredged sediments which have been disposed on land is highly dependent on redox shifts. The aim of the present work was to assess changes in sulphur, metal speciation (Zn, Fe, Cr y Cu and acidity caused by a polluted sediment oxidation event. Sediments were dessicated under controlled conditions and sulphide compounds (acid volatile sulphides-AVS- and sulphate, pH and neutralization potential were measured through time during 36 days. Zinc, Cu, Cr and Fe speciation (BCR metal sequential extraction procedure were measured at the beginning of the experiment and at day 22. An acid-base equilibrium method based on the BCR procedure was employed to assess the sediment acidification risk. Some of the re-suspension experiments were inoculated with an Acidithiobacillus ferrooxidans strain to assess biological catalysis on sulphide oxidation. Acid-base equilibrium results indicated the sediment sample had a significant acidification potential. Oxidation increased sulphate levels (56 to 2300 mg S kg-¹ in the desiccation experiment with a temporal evolution adjusted by a logistic model, and a 2100 to 3000 mg SO4 -² L-¹ increase for the resuspension experiments. Sulphide oxidation rates varied between 0 to 3.1.10-9 mg O2 kg-¹ s-¹ for the drying sediment. Zinc changes could be explained partially by ZnS conversion to ZnSO4 during oxidation. Iron reduction could be attributed to an increase in Fe oxides crystallinity. Acid-base equilibrium for the sample indicated it was a potentially acid-generating material. Zinc increased its bioavailability during drying and was the only metal that appeared in significant amounts in solution during re-suspension. Land-filling with dredged sediments could present increased metals bioavailability problems despite having an important and effective neutralization potential.La evaluación de los riesgos de acidificación por deposición de sedimentos dragados en superficie es muy dependiente de los

  17. Deciphering a multistage history affecting U-Cu(-Fe) mineralization in the Singhbhum Shear Zone, eastern India, using pyrite textures and compositions in the Turamdih U-Cu(-Fe) deposit

    Science.gov (United States)

    Pal, Dipak C.; Barton, Mark D.; Sarangi, A. K.

    2009-01-01

    The ˜200-km-long intensely deformed Singhbhum Shear Zone (SSZ) in eastern India hosts India’s largest U and Cu deposits and related Fe mineralization. The SSZ separates an Archaean cratonic nucleus to the south from a Mesoproterozoic fold belt in the North and has a complex geologic history that obscures the origin of the contained iron-oxide-rich mineral deposits. This study investigates aspects of the history of mineralization in the SSZ by utilizing new petrographic and electron microprobe observations of pyrite textures and zoning in the Turamdih U-Cu(-Fe) deposit. Mineralization at Turamdih is hosted in intensively deformed quartz-chlorite schist. Sulfides and oxides include, in inferred order of development: (a) magmatic Fe(-Ti-Cr) oxide and Fe-Cu(-Ni) sulfide minerals inferred to be magmatic (?) in origin; followed by (b) uranium, Fe-oxide, and Fe-Cu(-Co) sulfide minerals that predate most or all ductile deformation, and are inferred to be of hydrothermal origin; and (c) Fe-Cu sulfides that were generated during and postdating ductile deformation. These features are associated with the formation of three compositionally and texturally distinct pyrites. Pyrite (type-A), typically in globular-semiglobular composite inclusions of pyrite plus chalcopyrite in magnetite, is characterized by very high Ni content (up to 30,700 ppm) and low Co to Ni ratios (0.01-0.61). The textural and compositional characteristics of associated chalcopyrite and rare pyrrhotite suggest that this pyrite could be linked to the magmatic event via selective replacement of magmatic pyrrhotite. Alternatively, this pyrite and associated sulfide inclusions might be cogenetic with hydrothermal Fe-oxide. Type-B pyrite that forms elongate grains and irregular relics and cores of pyrite with high Co contents (up to 23,630 ppm) and high Co to Ni ratios (7.2-140.9) are interpreted to be related to hydrothermal mineralization predating ductile deformation. A third generation of pyrite (type C

  18. Thermoelectric transport properties of diamond-like Cu1-xFe1+xS2 tetrahedral compounds

    Science.gov (United States)

    Li, Yulong; Zhang, Tiansong; Qin, Yuting; Day, Tristan; Jeffrey Snyder, G.; Shi, Xun; Chen, Lidong

    2014-11-01

    Polycrystalline samples with the composition of Cu1-xFe1+xS2 (x = 0, 0.01, 0.03, 0.05, 0.1) were synthesized by a melting-annealing-sintering process. X-ray powder diffraction reveals all the samples are phase pure. The backscattered electron image and X-ray map indicate that all elements are distributed homogeneously in the matrix. The measurements of Hall coefficient, electrical conductivity, and Seebeck coefficient show that Fe is an effective n-type dopant in CuFeS2. The electron carrier concentration of Cu1-xFe1+xS2 is tuned within a wide range leading to optimized power factors. The lattice phonons are also strongly scattered by the substitution of Fe for Cu, leading to reduced thermal conductivity. We use Debye approximation to model the low temperature lattice thermal conductivity. It is found that the large strain field fluctuation introduced by the disordered Fe ions generates extra strong phonon scatterings for lowered lattice thermal conductivity.

  19. FePtCu alloy thin films: Morphology, L1{sub 0} chemical ordering, and perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, C.; Schletter, H.; Daniel, M.; Matthes, P.; Joehrmann, N.; Makarov, D.; Hietschold, M.; Albrecht, M. [Institute of Physics, Chemnitz University of Technology, D-09107 Chemnitz (Germany); Maret, M. [Laboratory of Science and Engineering of Materials and Processes (SIMaP), INP-Grenoble/CNRS/UJF, F-38402 Saint-Martin d' Heres (France)

    2012-10-01

    Rapid thermal annealing was applied to transform sputter-deposited Fe{sub 51}Pt{sub 49}/Cu bilayers into L1{sub 0} chemically ordered ternary (Fe{sub 51}Pt{sub 49}){sub 100-x}Cu{sub x} alloys with (001) texture on amorphous SiO{sub 2}/Si substrates. It was found that for thin film samples, which were processed at 600 Degree-Sign C for 30 s, the addition of Cu strongly favors the L1{sub 0} ordering and (001) texture formation. Furthermore, it could be revealed by transmission electron microscopy and electron backscatter diffraction that the observed reduction of the ordering temperature with Cu content is accompanied by an increased amount of nucleation sites forming L1{sub 0} ordered grains. The change of the structural properties with Cu content and annealing temperature is closely related to the magnetic properties. While an annealing temperature of 800 Degree-Sign C induces strong perpendicular magnetic anisotropy (PMA) in binary Fe{sub 51}Pt{sub 49} films, the addition of Cu systematically reduces the PMA. However, due to the enhancement of both the A1-L1{sub 0} phase transformation and the development of the (001) texture with increasing Cu content, lowering of the annealing temperature leads to a shift of the maximum perpendicular magnetic anisotropy towards alloys with higher Cu content. Thus, for an annealing temperature of 600 Degree-Sign C, the highest perpendicular magnetic anisotropy energy is found for the (Fe{sub 51}Pt{sub 49}){sub 91}Cu{sub 9} alloy. The smooth surface morphology, adjustable PMA, and high degree of intergranular exchange coupling make these films suitable for post-processing required for specific applications such as for sensorics or magnetic data storage.

  20. Nuclear excitation functions of proton-induced reactions (Ep = 35-90 MeV) from Fe, Cu, and Al

    Science.gov (United States)

    Graves, Stephen A.; Ellison, Paul A.; Barnhart, Todd E.; Valdovinos, Hector F.; Birnbaum, Eva R.; Nortier, Francois M.; Nickles, Robert J.; Engle, Jonathan W.

    2016-11-01

    Fe, Cu, and Al stacked foils were irradiated by 90 MeV protons at the Los Alamos Neutron Science Center's Isotope Production Facility to measure nuclear cross sections for the production of medically relevant isotopes, such as 52gMn, 54Mn, 48Cr, 55Co, 58mCo and 57Ni. The decay of radioactive isotopes produced during irradiation was monitored using high-purity germanium gamma spectroscopy over the months following irradiation. Proton fluence was determined using the natAl(p,x)22Na, natCu(p,x)62Zn natCu(p,x)65Zn, and natCu(p,x)56Co monitor reactions. Calculated cross sections were compared against literature values and theoretical TALYS predictions. Notably this work includes the first reported independent cross section measurements of natCu(p,x)58mCo and natCu(p,x)58gCo.

  1. Structure and properties of FeCoNiCrCu0.5Alx high-entropy alloy%FeCoNiCrCu0.5Alx高熵合金的结构和性能

    Institute of Scientific and Technical Information of China (English)

    李宝玉; 彭坤; 胡爱平; 周灵平; 朱家俊; 李德意

    2013-01-01

    Effects of Al content and heat treatment on the structure,hardness and electrochemical properties of FeCoNiCrCu0.5Alx high-entropy alloys were investigated.The phase structure of as-cast alloys evolves from FCC phase to BCC phase with the increase of Al content.The stable phase of FeCoNiCrCu0.5Alx high-entropy alloys will transform from FCC phase to FCC+BCC duplex phases when x value increases from 0.5 to 1.5.The hardness of BCC phase is higher than that of FCC phase,and the corrosion resistance of BCC phase is better than FCC phase in chlorine ion and acid medium.High hardness and good corrosion resistance can be obtained in as-cast FeCoNiCrCu05Al1.0 alloy.%研究Al含量和热处理对FeCoNiCrCu0.5Alx多主元高熵合金的相结构、硬度和电化学性能的影响规律.随着Al含量的增加,铸态合金的相结构由FCC相向BCC相转变.当x从0.5增加到1.5时,FeCoNiCrCu0.5Alx高熵合金的稳定结构由FCC结构向FCC+BCC双相结构转变.BCC相的硬度高于FCC相的,在氯离子及酸性介质中BCC相的耐腐蚀性均优于FCC相的.FeCoNiCrCu0.5Al1.0铸态合金具有高硬度和良好的抗腐蚀性能.

  2. Energy Parameters of Interfacial Layers in Composite Systems: Graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and Semiconductor (Si,Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb

    Directory of Open Access Journals (Sweden)

    B.P. Koman

    2015-12-01

    Full Text Available On the basis of the non-equilibrium thermodynamics relations and the surface physics phenomena we calculate adhesion and energy parameters to characterize the interfacial interactions in graphene – (Si, Cu, Fe, Co, Au, Ag, Al, Ru, Hf, Pb and semiconductor (Si, Ge – (Fe, Co, Cu, Al, Au, Cr, W, Pb systems. We analyze trends of the interfacial energy, interfacial tension, work of adhesion and the energy of adhesive bonds on the contacting element’s atomic number in the periodic table and on the electronegativity difference of interacting elements. Thus, this work provides theoretical basis for the development of new composite materials.

  3. 高质量尺寸可调CuFeS2纳米晶的合成与光电性质%Synthesis and Photoelectric Properties of High Quality CuFeS2 Nanocrystals with Tunable Sizes

    Institute of Scientific and Technical Information of China (English)

    张卓磊; 李冬泽; 刘志辉; 解仁国

    2014-01-01

    制备了单分散性良好且尺寸可调的具有荧光性质的CuFeS2纳米晶,利用紫外-可见吸收光谱( UV-Vis)、荧光光谱、透射电子显微镜( TEM)、X射线粉末衍射( XRD)、元素分析和光电流测试等技术对其组分和结构进行了表征,分析了CuFeS2纳米晶尺寸变化对吸收光谱和光电响应行为的影响规律。随着CuFeS2纳米晶尺寸增大,其吸收峰位表现出符合量子尺寸效应的相应红移;具有荧光性质的CuFeS2纳米晶可控制备预示其在生物医学成像和光电器件等领域具有应用前景。%The mono-dispersed CuFeS2 nanocrystals( NCs) with tunable sizes were synthesized and characte-rized by UV-Vis-NIR absorption spectroscopy, transmission electron microscopy( TEM) , X-ray powder diffrac-tion( XRD) and inductively coupled plasma( ICP) . It is found that the as-prepared CuFeS2 NCs show photolu-minescence in visible region. The photo-responsive properties of CuFeS2 NCs further reveal their suitability as optically active components for optoelectronic devices and the growth in size due to the quantum size effect. All the experimental results indicate that as-prepared CuFeS2 NCs with characteristics of fluorescence has potential application in biomedical imaging and optoelectronic devices.

  4. Influence of Al and Cu elements on the microstructure and properties of (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.C., E-mail: fanqichao@126.com [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Li, B.S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Y. [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2014-11-25

    Highlights: • Relationship between entropy and enthalpy on phase formation was specified. • Phase changed from fcc to fcc plus bcc and then bcc phase. • Mechanical properties changed from plasticity to brittleness. • Young’s modulus, hardness and yield strength increased with Al element. - Abstract: (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys were designed using the strategy of equiatomic ratio, high entropy of mixing and different mixing enthalpies of atom-pairs. The effects of entropy and enthalpy on phase forming process of the alloys were clearly studied and the influences of Al and Cu elements on the microstructure and mechanical properties were investigated. As long as Al element level increased from 0.5 to 1, the microstructure of the alloy system changed from fcc structure to duplex fcc plus bcc structure and then a single bcc structure. Increase of Al element greatly enhanced the Young’s modulus, hardness and yield strength of these alloys. (FeCrNiCo)Al{sub 0.75}Cu{sub 0.5} alloy got the most excellent comprehensive mechanical properties; its fracture strength and plastic strain were as high as 2270 MPa, and 42.70%, respectively. Cu-rich phase formed in the alloys when Cu element was in high levels. Increase of Cu element greatly decreased fracture strength of the high-entropy alloys when Al element was in the high level of x = 1.

  5. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    Science.gov (United States)

    Mao, J.; Fan, S.; Jacob, D. J.; Travis, K. R.

    2013-01-01

    The hydroperoxyl radical (HO2) is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions Cu(I)/Cu(II) and Fe(II)/Fe(III) to rapidly convert HO2 to H2O in aqueous aerosols. The implied HO2 uptake and conversion to H2O significantly affects global model predictions of tropospheric OH, ozone, carbon monoxide (CO) and other species, improving comparisons to observations in the GEOS-Chem model. It represents a previously unrecognized positive radiative forcing of aerosols through the effects on the chemical budgets of major greenhouse gases including methane and hydrofluorocarbons (HFCs).

  6. REE and Trace Element Geochemistry of Yinachang Fe-Cu-REE Deposit, Yunnan Province, China

    Institute of Scientific and Technical Information of China (English)

    杨耀民; 涂光炽; 胡瑞忠

    2004-01-01

    REE and other trace elements in ores, wall rocks, alkaline volcanic rocks and diabase dikes have been determined in the Yinachang Fe-Cu-REE deposit. Comparative studies of REE and trace element geochemical characteristics of these geological bodies indicate that the ores and alkaline volcanic rocks contain abundant REE and Y (65.9-4633)×10-6, with higher abundances of As, Mo, Nb, Co and U than those of the crust. Their chondrite-normalized patterns show a strong enrichment of LREE and a positive Eu anomaly, in contrast to those of the dolomites which are characterized by slight LREE enrichment and moderate negative Eu anomaly. The REE patterns of ores are similar to those of hydrothermal sediment cores in the East Pacific Rise, whereas the REE patterns of dolomites are similar to those of PAAS (Post-Archean Average Shale). In combination with the geological setting of the deposit, the primary ore-forming fluids might have higher REE and volatile elements, and might have been derived from mantle degassing, or the alkaline volcanic magmas. The Yinachang Fe-Cu-REE ore deposit is considered to be of volcanic exhalation-hydrothermal sedimentary origin.

  7. Thermodynamics of Fe Cu alloys as described by a classic potential

    Science.gov (United States)

    Caro, A.; Caro, M.; Lopasso, E. M.; Turchi, P. E. A.; Farkas, D.

    2006-03-01

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. [M. Ludwig, D. Farkas, D. Pedraza, S. Schmauder, Model. Simul. Mater. Sci. Eng. 6 (1998) 19]. In this work we extract thermodynamic information from this interatomic potential. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials. Improved potentials, primarily for the pure components, should be developed to account for proper phase stability in the solid phase up to melting. Finally we suggest an approach to improve existing potentials for this system.

  8. Thermodynamics of Fe-Cu alloys as described by a classic potential

    Energy Technology Data Exchange (ETDEWEB)

    Caro, A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States)]. E-mail: caro2@llnl.gov; Caro, M. [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Lopasso, E.M. [Centro Atomico Bariloche, 8400 Bariloche (Argentina); Turchi, P.E.A. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States); Farkas, D. [Department of Materials Science and Engineering, Virginia Tech., Blacksburg, VA 24061 (United States)

    2006-03-01

    The Fe-Cu system is of relevance to the nuclear industry because of the deleterious consequences of Cu precipitates in the mechanical properties of Fe. Several sets of classical potentials are used in molecular dynamics simulations studies of this system, in particular that proposed by Ludwig et al. [M. Ludwig, D. Farkas, D. Pedraza, S. Schmauder, Model. Simul. Mater. Sci. Eng. 6 (1998) 19]. In this work we extract thermodynamic information from this interatomic potential. We obtain equilibrium phase diagram and find a reasonable agreement with the experimental phases in the regions of relevance to radiation damage studies. We compare the results with the predicted phase diagram based on other potential, as calculated in previous work. We discuss the disagreements found between the phase diagram calculated here and experimental results, focusing on the pure components and discuss the applicability of these potentials. Improved potentials, primarily for the pure components, should be developed to account for proper phase stability in the solid phase up to melting. Finally we suggest an approach to improve existing potentials for this system.

  9. DETERMINATION OF Cu, Fe, Mn, Zn AND FREE FATTY ACIDS IN PEQUI OIL

    Directory of Open Access Journals (Sweden)

    Aparecida M. S. Mimura

    2016-06-01

    Full Text Available Pequi (Caryocar brasiliense Camb., a typical fruit of the Brazilian Cerrado, is an important source of micronutrients and fatty acids. In this work, a new approach for the acid digestion (using H2SO4, HNO3 and H2O2 of pequi oil samples and the determination of Cu, Fe, Zn and Mn by flame atomic absorption spectrometry (F AAS was employed. Capillary zone electrophoresis (CZE was used for free fatty acid (FFA determination after simple and fast extraction with heated ethanol. Good results regarding precision (RSD < 10%, in most cases, sensitivity and adequate LOD and LOQ values were obtained. The accuracy was evaluated using spike tests and the recoveries were from 97 to 107%. The analytes were investigated in four different pequi oil samples. Fe was the trace element with the highest concentration (from 1.99 to 10.3 mg/100 g, followed by Zn, Mn and Cu (1.15 to 3.19, 0.42 to 0.91 and 0.31 to 0.56 mg/100 g, respectively. The main FFA found were oleic acid and palmitic acid (1.61 to 10.7 and 0.82 to 2.69 g/100 g, respectively, while linoleic acid (0.50 g/100 g was detected in only one sample. The pequi oil chemical composition showed good characteristics to be used as a food additive, in cosmetic formulations and for traditional medicine.

  10. High plastic Zr-Cu-Fe-Al-Nb bulk metallic glasses for biomedical applications

    Science.gov (United States)

    Wang, Shu-shen; Wang, Yun-liang; Wu, Yi-dong; Wang, Tan; Hui, Xi-dong

    2015-06-01

    Four Zr-Cu-Fe-Al-based bulk metallic glasses (BMGs) with Zr contents greater than 65at% and minor additions of Nb were designed and prepared. The glass forming abilities, thermal stabilities, mechanical properties, and corrosion resistance properties of the prepared BMGs were investigated. These BMGs exhibit moderate glass forming abilities along with superior fracture and yield strengths compared to previously reported Zr-Cu-Fe-Al BMGs. Specifically, the addition of Nb into this quaternary system remarkably increases the plastic strain to 27.5%, which is related to the high Poisson's ratio and low Young's and shear moduli. The Nb-bearing BMGs also exhibit a lower corrosion current density by about one order of magnitude and a wider passive region than 316L steel in phosphate buffer solution (PBS, pH 7.4). The combination of the optimized composition with high deformation ability, low Young's modulus, and excellent corrosion resistance properties indicates that this kind of BMG is promising for biomedical applications.

  11. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    WANG HaiPeng; LUO BingChi; CHANG Jian; WEI BingBo

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calorimeter over a wide temperature range from 1482 to 1818 K. A maximum undercooling of 221 K (0.13 Tm) was achieved and the specific heat was determined as 44.71 J·mol-1·K-1. The excess specific heat, enthalpy change, entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results. It was found that the calculated results by traditional estimating methods can only describe the solidification process under low undercooling conditions. Only the experimental results can reflect the reality under high undercooling conditions. Meanwhile, the thermal diffusivity, thermal conductivity, and sound speed were derived from the present experimental results. Furthermore, the solidified microstructural morphology was examined, which consists of (Fe) and (Cu) phases. The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  12. Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Tanhong Cai

    2002-12-31

    Three papers are included in this dissertation. The first paper: ''Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED studies'', is in press with ''Surface Science''. The second paper: ''An STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface'' is submitted to ''Physical Review B, Rapid Communication''. The third paper: ''Pseudomorphic starfish: arrangement of extrinsic metal atoms on a quasicrystalline substrate'' is submitted to ''Nature''. Following the third paper are general conclusions and appendices that document the published paper ''Structural aspects of the three-fold surface of icosahedral Al-Pd-Mn'' (appearing in volume 461, issue 1-3 of ''Surface Science'' on page L521-L527, 2000), the design as well as the specifications of the aluminum evaporator used in the aluminum deposition study in this dissertation, an extended discussion of the aluminum deposition on the quasicrystalline surface, and the STM database.

  13. Specific heat and related thermophysical properties of liquid Fe-Cu-Mo alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The specific heat and related thermophysical properties of liquid Fe77.5Cu13Mo9.5 monotectic alloy were investigated by an electromagnetic levitation drop calo-rimeter over a wide temperature range from 1482 to 1818 K.A maximum under-cooling of 221 K(0.13 Tm)was achieved and the specific heat was determined as 44.71 J·mol1·K1.The excess specific heat,enthalpy change,entropy change and Gibbs free energy difference of this alloy were calculated on the basis of experimental results.It was found that the calculated results by traditional esti-mating methods can only describe the solidification process under low under-cooling conditions.Only the experimental results can reflect the reality under high undercooling conditions.Meanwhile,the thermal diffusivity,thermal conductivity,and sound speed were derived from the present experimental results.Furthermore,the solidified microstructural morphology was examined,which consists of(Fe)and(Cu)phases.The calculated interface energy was applied to exploring the correlation between competitive nucleation and solidification microstructure within monotectic alloy.

  14. Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Tanhong [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Three papers are included in this dissertation. The first paper: ''Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED studies'', is in press with ''Surface Science''. The second paper: ''An STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface'' is submitted to ''Physical Review B, Rapid Communication''. The third paper: ''Pseudomorphic starfish: arrangement of extrinsic metal atoms on a quasicrystalline substrate'' is submitted to ''Nature''. Following the third paper are general conclusions and appendices that document the published paper ''Structural aspects of the three-fold surface of icosahedral Al-Pd-Mn'' (appearing in volume 461, issue 1-3 of ''Surface Science'' on page L521-L527, 2000), the design as well as the specifications of the aluminum evaporator used in the aluminum deposition study in this dissertation, an extended discussion of the aluminum deposition on the quasicrystalline surface, and the STM database.

  15. Heat treatment of the EN AC-AlSi9Cu3(Fe alloy

    Directory of Open Access Journals (Sweden)

    J. Pezda

    2010-04-01

    Full Text Available Silumins are widely used in automotive, aviation and shipbuilding industries; as having specific gravity nearly three times lower than specific gravity of cast iron the silumins can be characterized by high mechanical properties. Additionally, they feature good casting properties, good machinability and good thermal conductivity. i.e. properties as required for machinery components operating in high temperatures and at considerable loads. Mechanical properties of the silumins can be upgraded, implementing suitably selected heat treatment. In the paper is presented an effect of modification and heat treatment processes on mechanical properties of the EN AC-AlSi9Cu3(Fe alloy. Investigated alloy has undergone typical processes of modification and refining, and next heat treatment. Temperature range of the heat treatment operations was determined on base of curves from the ATD method. Obtained results concern registered melting and solidification curves from the ATD method and strength tests. On base of the performed tests one has determined range of the heat treatment parameters which would assure obtainment of the best possible mechanical properties of the EN AC-AlSi9Cu3(Fe alloy.

  16. X?-DVM modelling of oxygen transport in YBa2Cu3O7-? and SrFeO3

    Science.gov (United States)

    Yuryeva, Elmira I.

    The reasons for oxygen transport in YBa2Cu3O7-? and SrFeO3 were investigated, using the X?-discrete variation method. Reduced binding energy and other parameters of the electronic energy structure were calculated for a number of crystal fragments within the T and O phases of YBa2Cu3O7-? and the cubic phase of SrFeO3. The following results were obtained: (i) test calculations of reduced binding energy confirmed that high temperature should be a condition of existence of the T phase, as compared with the O phase of YBa2Cu3O7-?; (ii) an increase in temperature up to ?400°C points to the beginning of the Jahn-Teller dynamic effect in SrFeO3; and (iii) transport of neutral and charged oxygen atoms results in distributions of stable and unstable oxygen vacancies, respectively.

  17. Effect of Co element on microstructure and mechanical properties of FeCoxNiCuAl alloys

    Institute of Scientific and Technical Information of China (English)

    Yanxin ZHUANG; Wenjie LIU; Pengfei XING; Fei WANG; Jicheng HE

    2012-01-01

    FeCoxNiCuAl (x values in molar ratio,x=0.2,0.5,1,1.5,2 and 3) alloys were prepared using a suck-casting method.The effect of Co element on phase constituents,microstructure and mechanical properties of the FeCoxNiCuAl alloys was investigated using X-ray diffraction,scanning electron microscopy,optical microscopy and compressive tests.It was found that the Co addition has a significant influence on the structure and properties of the FeCoxNiCuAl alloys.The alloys have typical dendrite microstructure,and are composed of a simple fcc structure and bcc structure.The addition of Co promotes the formation of fcc phase in the alloys,retards the compressive strength and hardness of the alloys,and enhances the plasticity of the alloys.

  18. Structural and magnetic properties of epitaxial delafossite CuFeO{sub 2} thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Toyanath; Senty, Tess R.; Trappen, Robbyn; Zhou, Jinling; Borisov, Pavel; Holcomb, Mikel B.; Bristow, Alan D.; Lederman, David [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Chen, Song; Song, Xueyan [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506-6070 (United States); Ferrari, Piero; Cabrera, Alejandro L. [Pontificia Universidad Catolica, Instituto de Física, Santiago (Chile)

    2015-01-07

    Growth of pure phase delafossite CuFeO{sub 2} thin films on Al{sub 2}O{sub 3} (00.1) substrates by pulsed laser deposition was systematically investigated as a function of growth temperature and oxygen pressure. X-ray diffraction, transmission electron microscopy, Raman scattering, and x-ray absorption spectroscopy confirmed the existence of the delafossite phase. Infrared reflectivity spectra determined a band edge at 1.15 eV, in agreement with the bulk delafossite data. Magnetization measurements on CuFeO{sub 2} films demonstrated a phase transition at T{sub C} ≈ 15 ± 1 K, which agrees with the first antiferromagnetic transition at 14 K in the bulk CuFeO{sub 2}. Low temperature magnetic phase is best described by commensurate, weak ferromagnetic spin ordering along the c-axis.

  19. Bio-active trace elements (cd, cu, fe, ni) in the oligotrophic south china sea

    Science.gov (United States)

    Wen, L.-S.; Jiann, K.-T.; Liu, K.-K.

    2003-04-01

    Bio-active trace elements (Cu, Ni, Cd, Fe) in seawater play a critical role in regulating oceanic phytoplankton growth and, hence, may influence global carbon cycle. However, their in-situ speciation and bio-reactivity are poorly understood. Dissolved copper and nickel are believed to be present in seawater predominantly as low molecular weight soluble organic complexes which are readily available to marine organism and immune from particle scavenging. Dissolved iron is believed to exist predominantly as high molecular weight colloidal species. Using ultraclean ultrafiltration and ion exchange/affinity chelating chemistry, we demonstrate that in the oligotrophic ocean waters, these four bio-active elements have distinctive characteristics of speciation and reactivity, even though they display similar nutrient-type distributions. For dissolved Cu, the concentration increased from 0.9 nM in the surface water to 3 nM at depths below 500 m; for dissolved Ni, 2˜9 nM; for dissolved Cd, 0.01˜0.9 nM; for dissolved Fe, 0.1˜0.6 nM. All four elements showed a subsurface minimum around 60 m deep, which corresponded to the subsurface Chl a maximum, indicating strong biological interactions with these elements. Detailed analysis revealed distinct size distribution and chemical reactivity for each element. For Cu, more than 50% in surface water was in smaller than 1kDa labile forms; the strongly complexed inert form increased from 28% at surface to 50% below 500 meter; the colloidal form Cu decreased from 12% at surface to a minimum of 6% at 60 meter, and then gradually increased to 16% in deeper water. For Ni, more than 80% was in smaller than 1kDa labile form, and very small fraction (˜5%) in colloidal from. For Cd, almost all dissolved fraction was in smaller than 1kDa labile form. As for Fe, its dynamic nature in water column caused by complicated bio-interactions was evident. This study indicated that, with preferential uptake of trace elements by different phytoplankton

  20. Tectono-metallogenetic evolution of the Fe-Cu deposit of Dominga, northern Chile

    Science.gov (United States)

    Veloso, E.; Cembrano, J.; Arancibia, G.; Heuser, G.; Neira, S.; Siña, A.; Garrido, I.; Vermeesch, P.; Selby, D.

    2016-10-01

    The Dominga district in northern Chile (2082 Mt at 23.3 % Fe, 0.07 % Cu) shows a spatial and genetic affinity among distinctive structural elements and Fe-Cu-rich paragenetic mineral assemblages. Deep seated, NE-to-E striking structural elements form a right-lateral duplex-like structural system (early structural system, ESS) that cuts a regionally extensive alteration (stage I) zone. The EES system served as a locus and as path for the emplacement of biotite-magnetite alteration/mineralization (stage IIa) as veins and Fe-bearing layers following altered volcano sedimentary strata. NW-striking actinolite-magnetite hydrothermal breccias, coeval with and part of the ESS, include apatite (stage IIb) crystallized at 127 ± 15 Ma (U-Pb, 2σ). The ESS was also the locus of subsequent alteration/mineralization represented by K-feldspar, epidote, and albite (stage IIIa) and Fe-Cu-rich (vermiculite-anhydrite-chalcopyrite, stage IIIb) mineral associations. Shallowly developed, NNE-striking, left-lateral structural elements defining the El Tofo Structural System (ETSS)—probably part of the Atacama Fault System—clearly crosscut the ESS. Minerals associated with alteration/mineralization stage IIIb also occur as veins and as part of hydrothermal breccias of the ETSS, marking the transition from the ESS to ETSS. Molybdenite associated with alteration/mineralization stage IIIb yielded a Re-Os age of 127.1 ± 0.7 Ma (2σ). Both the ESS and ETSS were cut by left-lateral, NW- to E-striking shallowly developed structural elements (Intermediate Structural System, ISS) on which a hematite-calcite assemblage (stage IV) occurs mostly as infill material of veins and fault veins. The ISS is cut by N-striking, left-lateral, and shallowly developed structural elements (Late Structural System, LSS) showing no evidence of alteration/mineralization. Estimated strain and stress fields indicate an overall NW-trending shortening/compression and NE-trending stretching/tension strike-slip regime

  1. Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-Cu4FeAlCO3

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunxia; XU Chenghua; FENG Liangrong; SUO Jishuan; QIU Fali

    2005-01-01

    The present work synthesizes La-Cu4FeAlCO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-Cu4FeAlCO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-Cu4FeAlCO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hydroxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-Cu4FeAlCO3, under the reaction conditions of the molar ratio of phenol/H2O2 1/2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 120 min, 10 mL distilled water as solvent. Moreover, a kinetic equation of and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-Cu+-OH species are detected in La-Cu4FeAlCO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is proposed, which is supposed that HO-Cu+-OH species are transition state in this reaction.

  2. Study of structural and magnetic properties of (Co–Cu)Fe{sub 2}O{sub 4}/PANI composites

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, Mohd., E-mail: md.hashim09@gmail.com [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Alimuddin [Department of Applied Physics, Aligarh Muslim University, Aligarh 202 002 (India); Shirsath, Sagar E. [Spin Device Technology Centre, Department of Information Engineering, Shinshu University, Nagano 380-8553 (Japan); Meena, S.S. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kotnala, R.K. [National Physical Laboratory (CSIR), Dr. K.S. Krishnan Road, New Delhi 110 012 (India); Kumar, Shalendra [Department of Physics, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Bhatt, Pramod [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Jotania, R.B. [Department of Physics, School of Science, Gujarat University, Ahmedabad 380 009 (India); Kumar, Ravi [Centre for Material Science Engineering, National Institute of Technology, Hamirpur 171 005, HP (India)

    2013-08-15

    The nanocomposites of the polyaniline and Co{sub 1−x}Cu{sub x}Fe{sub 2}O{sub 4} (PANI/CoCuFe) were prepared by in-situ oxidative polymerization of aniline. Prepared nanocomposites samples were characterized by using various experimental techniques like X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), Mössbauer spectroscopy and ultraviolet–visible spectrophotometry (UV–VIS). The elemental analysis as obtained from the energy dispersive X-ray spectroscopy (EDAX) measurement is in close agreement with the expected composition from the stoichiometry of the reactant solutions. XRD result confirms that all the samples have the single phase cubic spinel structure. Unit cell parameter ‘a’ is found to decrease with the increase in copper ion substitution. The crystallite size was investigated by using the Debye–Scherer formula and it was found in the range of ∼28–37 nm. FE-SEM confirmed the homogeneous and well defined surface morphology of the synthesized samples. FT-IR study showed the main absorption bands corresponding to the spinel structure those arose due to the tetrahedral and octahedral stretching vibrations. Cation distribution was estimated using XRD data. Hysteresis measurements revealed that the saturation magnetization decreased with increase in Cu{sup 2+} substitution. Magnetic environment of {sup 57}Fe in Cu-doped cobalt ferrite was investigated by using Mössbauer spectroscopy. Mössbauer study evidenced the ferrimagnetic behavior of the synthesized samples. - Highlights: • Crystallite size decreases with increasing Cu{sup 2+} substitution. • The prepared samples show the formation of single phase cubic spinel structure. • Cation distribution shows that Cu and Co ions shows strong preference toward octahedral B site. • Magnetization decreases with increasing Cu{sup 2+} substitution. • Mössbauer study shows

  3. Simultaneously degradation of 2,4-dichlorophenol and EDTA in aqueous solution by the bimetallic Cu-Fe/O₂ system.

    Science.gov (United States)

    Liu, Xin; Fan, Jin-Hong; Ma, Lu-Ming

    2015-01-01

    Oxidative degradation of aqueous organic contaminants 2,4-dichlorophenol (2,4-DCP) using ethylenediaminetetraacetic acid (EDTA)-enhanced bimetallic Cu-Fe system in the presence of dissolved oxygen was investigated. The proposed process was applied for the pH range of 3~7 with the degradation efficiency of 2,4-DCP and EDTA varying within 10 %, and achieved at 100 % degradation of 40 mg L(-1) 2,4-DCP in 1 h, at the initial pH of 3, 25 g L(-1) of bimetallic Fe-Cu powder (WCu/WFe = 0.01289) and initial EDTA of 0.57 mM. However, the removal efficiency of 2,4-DCP in control tests were 7.52 % (Cu-Fe/O2 system) and 84.32 % (EDTA-enhanced Fe/O2 process), respectively, after 3 h, reaction. The proposed main mechanism, involves the in situ generation of H2O2 by the electron transfer from Fe(0) to O2 which was enhanced by ethylenediaminetetraacetic acid (EDTA), and the in situ generation of ·OH via advanced oxidation reaction. Accordingly, 2,4-DCP was attacked by ·OH to achieve complete dechlorination and low molecular weight organic acids, even mineralized. Systematic studies on the effects of initial EDTA and 2,4-DCP concentration, Cu-Fe dosing, Cu content, and pH revealed that these effects need to be optimized to avoid the excessive consumption of ·OH and new EDTA and heavy metal Cu pollution.

  4. Synthesis of mesoporous Cu/Mg/Fe layered double hydroxide and its adsorption performance for arsenate in aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    Yanwei Guo; Zhiliang Zhu; Yanling Qiu; Jianfu Zhao

    2013-01-01

    The mesoporous Cu/Mg/Fe layered double hydroxide (Cu/Mg/Fe-LDH) with carbonate intercalation was synthesized and used for the removal of arsenate from aqueous solutions.The Cu/Mg/Fe-LDH was characterized by Fourier transform infrared spectrometry,X-ray diffraction crystallography,scanning electron microscopy,X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller.Effects of various physico-chemical parameters such as pH,adsorbent dosage,contact time and initial arsenate concentration on the adsorption of arsenate onto Cu/Mg/Fe-LDH were investigated.Results showed that it was efficient for the removal of arsenate,and the removal efficiency of arsenate increased with the increment of the adsorbent dosage,while the arsenate adsorption capacity decreased with increase of initial pH from 3 to 11.The adsorption isotherms can be well described by the Langmuir model with R2 > 0.99.Its adsorption kinetics followed the pseudo second-order kinetic model.Coexisting ions such as HPO42-,CO32-,SO42-and NO3-could compete with arsenate for adsorption sites on the Cu/Mg/Fe-LDH.The adsorption of arsenate on the adsorbent can be mainly attributed to the ion exchange process.It was found that the synthesized Cu/Mg/Fe-LDH can reduce the arsenate concentration down to a final level of < 10 μg/L under the experimental conditions,and makes it a potential material for the decontamination of arsenate polluted water.

  5. Correlation between K, Mn, Fe, Cu and Zn in natural honeys from Eucalyptus sources

    Directory of Open Access Journals (Sweden)

    Silvânia V. M. Mattos

    1998-01-01

    Full Text Available Thirty-five natural honey samples from three apicultural regions of the state of Minas Gerais, Brazil, were collected from honeybee hives under various climatic conditions over a two-year period. The beehives were located in the districts of Bom Jesus do Amparo, Barão de Cocais and São Gonçalo do Rio Abaixo, all within a 100 km radius of Belo Horizonte, Minas Gerais, Brazil. The pollinic spectrum, color and ash, moisture, K, Fe, Mn, Cu and Zn contents were determined. Elemental analysis were done by flame atomic absorption spectrometry. Accuracy and precision were verified by recovery tests and relative standard deviation, respectively. The mean mineral contents encountered were K = 1130; Mn = 3.88; Fe = 2.79; Zn = 2.34 and Cu = 0.54 µ g/g. During the dry season, several species of Eucalyptus pollen grains predominated, with Vernonia pollen grains present in lower abundance. In the rainy season, there was an inversion of dominance. Statistical treatment of results, separated according to comb and season, showed statistically equivalent means, although some good correlation indices (p = 0.05 were obtained, e.g. between percent Eucalyptus pollen grains and Mn content (0.450, between Fe and Zn (0.698 and between K and Mn (0.738.Foram coletadas 35 amostras de mel natural em diferentes condições climáticas, por um período de dois anos. Os apiários se localizavam nos distritos de Bom Jesus do Amparo, Barão de Cocais e São Gonçalo do Rio Abaixo, a cerca de 100 km de Belo Horizonte, a capital do Estado de Minas Gerais, Brasil. As amostras foram analisadas quanto aos teores de K, Fe, Mn, Cu, Zn, espectro polínico, cor, cinzas e umidade. As médias encontradas foram: K = 1130; Mn = 3,88; Fe = 2,79; Zn = 2,34 e Cu = 0,54 µ g/g. No período de seca houve predomínio de grãos de pólen de origem de espécies de Eucalyptus e, em menor extensão de Vernonia. No período chuvoso, houve uma inversão dessa proporção. O tratamento estat

  6. Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Maciej Kapkowski

    Full Text Available In this study, we investigated different metal pairings of Au nanoparticles (NPs as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE. Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63% and selectivity (ca. 70% to HYNE.

  7. Crystal structure of CuFeInSe{sub 3} from X-ray powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Mora, Asiloe J.; Delgado, Gerzon E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela); Grima-Gallardo, Pedro [Centro de Estudios de Semiconductores, Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101 (Venezuela)

    2007-02-15

    The crystal structure of the adamantane compound CuFeInSe{sub 3}, belonging to the system (CuInSe{sub 2}){sub 1-x}(FeSe){sub x} with x=0.5, was analyzed using X-ray powder diffraction data. Several model structures were derived from the structure of the selenium rich phase CuInSe{sub 2.3} by permuting the cations in the available Wyckoff positions. The refinement of the best model by the Rietveld method in the tetragonal space group P anti 42c (N 112), Z=1, with unit cell parameters a=5.7762(2) Aa, c=11.5982(7) Aa and V=386.97(3) Aa{sup 3} led to R{sub p}=8.0%, R{sub wp}=9.6%, R{sub exp}=6.2% and {chi}{sup 2}=1.7 for 134 independent reflections. The model that best fitted the diffraction data has the following atomic distribution: Cu in Wyckoff site 2f; Fe in Wyckoff site 2d; In in Wyckoff site 2b and 1/3Cu, 1/3Fe, 1/3In in Wyckoff site 2f; Se in Wyckoff site 8n. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Bleaching effect and nonvola-tile holographic storage in doubly doped LiNbO3:Fe:Cu crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The bleaching effect, i. e. the crystal shows that decoloration after it is illuminated by ultraviolet light, has been observed in congruent LiNbO3:Fe :Cu crystals. Based on this bleaching effect, a new technique including the reco rding phase by two interfering red beams and fixing phase by both UV light and a coherent red beam has been experimentally investigated to realize nonvolatile holographic storage in LiNbO3:Fe:Cu. The results of proof-of-concept experiments confirm that bleaching effect becomes an alternative physical mechanism for nonv olatile holographic storage with high recording sensitivity and weak light-induced scattering noise.

  9. Heterogeneous UV/Fenton catalytic degradation of wastewater containing phenol with Fe-Cu-Mn-Y catalyst

    Institute of Scientific and Technical Information of China (English)

    郑展望; 雷乐成; 徐生娟; 岑沛霖

    2004-01-01

    The heterogeneous UV/Fenton process with the appropriate amount of Fe-Mn-Cu-Y as catalyst was developed and various operation conditions for the degradation of phenol were evaluated. The results indicated that by using the heterogeneous UV/Fenton process, the CODcr removal rate reached almost 100% for wastewater containing phenol. Compared with the homogeneous process, the developed catalyst could be used at wider pH range in the UV/Fenton process. Comparison of various heterogeneous process showed that heterogeneous UV/Fenton process was best. The heterogeneous UV/Fenton process with Fe-Mn-Cu-Y catalyst is highly efficient in degrading various organic pollutants.

  10. Efficiency of Chitosan for the Removal of Pb (II), Fe (II) and Cu (II) Ions from Aqueous Solutions

    OpenAIRE

    Soheil Sobhanardakani; Raziyeh Zandipak; Hassan Parvizimosaed; Arash Javanshir Khoei; Mehran Moslemi; Mahsa Tahergorabi; Seyed Mehdi Hosseini; Parisa Delfieh

    2014-01-01

    Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II), Fe(II) and Cu(II) ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II), Fe(II) and Cu(II) from aqueous s...

  11. Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity

    Science.gov (United States)

    Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.

    2016-12-01

    Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.

  12. An insight into the metal coordination and spectroscopic properties of artistic Fe and Fe/Cu logwood inks

    Science.gov (United States)

    Bronzato, Maddalena; Zoleo, Alfonso; Biondi, Barbara; Centeno, Silvia A.

    2016-01-01

    Fe- and Fe/Cu-based logwood inks were synthesized following recipes in nineteenth and early twentieth century manuals and were characterized by EPR, ESI-MS, FTIR, and Raman spectroscopies. This multi-technique approach allowed us to shed light on the structures of the complexes responsible for the inks' colors and to obtain vibrational signatures that can be used to identify the different inks in works of art and in historic documents. Information on the nature and chemical properties of the complexes formed between a dye and a mordant is important as these determine, at least in part, their lightfastness. EPR permitted to determine the coordination environment of the metallic ions. The results of the ESI-MS analysis demonstrated, for the first time, the breakdown of the hematein molecule during the ink preparation, and that the colorants are formed by the complexation of the metallic ions by hematein breakdown products, mainly catechol and/or bicyclic compounds. The FTIR spectra obtained were found to be dominated by bands due to the binding medium and sulfates used as reagents. The Raman analysis showed that the characteristic features for the different inks studied depend on the historic recipe used, attesting to the challenges that their identification and characterization in works of art present. In the Raman spectra of the inks applied on paper, broadening of bands in the 750-400 cm- 1 range are observed when compared to the spectra of the inks' powders, possibly due to the interaction of the compounds with the cellulose in the substrate.

  13. Synthesis, identification and thermal decomposition of double sulfites like Cu2SO3·MSO3·2H2O (M=Cu, Fe, Mn or Cd)

    OpenAIRE

    2000-01-01

    Texto completo: acesso restrito. p.17–27 Double sulfites with empirical formula Cu2SO3·MSO3·2H2O (where M is Cu, Fe, Mn, or Cd) were obtained by saturation with sulfur dioxide gas of an aqueous mixture of MII sulfate and copper sulfate at room temperature. The salts obtained were identified by infrared spectra, X-ray powder diffraction and elemental analysis. The compounds studied are isostructural with the CuII replacement by MnII, FeII, and CdII in Chevreul’s salt (Cu2SO3·CuSO3·2H2O). Th...

  14. Suppression of spin pumping between Ni{sub 80}Fe{sub 20} and Cu by a graphene interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Gannett, Will; Keller, Mark W., E-mail: mark.keller@nist.gov; Nembach, Hans T.; Silva, Thomas J.; Chiaramonti, Ann N. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2015-06-07

    We compare ferromagnetic resonance measurements of Permalloy Ni{sub 80}Fe{sub 20} (Py) films sputtered onto Cu(111) films with and without a graphene (Gr) interlayer grown by chemical vapor deposition before Py deposition. A two-angle sputtering method ensured that neither Gr nor Py was degraded by the sample preparation process. We find the expected damping enhancement from spin pumping for the Py/Cu case and no detectable enhancement for the Py/Gr/Cu case. Since damping is sensitive to effects other than spin pumping, we used magnetometry to verify that differences in Py magnetostatic properties are not responsible for the difference in damping. We attribute the suppression of spin pumping in Py/Gr/Cu to the large contact resistance of the Gr/Cu interface.

  15. EXAFS study on solute precipitation in FeCu alloy induced by energetic electron bombardments and thermal aging

    Science.gov (United States)

    Fujimura, Y.; Yoshizaki, H.; Nakagawa, Shou; Okamoto, Y.; Ishikawa, N.; Saitoh, Y.; Hori, F.; Iwase, A.

    2015-07-01

    The extended X-ray absorption fine structure (EXAFS) measurement is a useful tool for the observation of local atomic arrangements around selected atoms. We performed EXAFS measurements for the electron-irradiated and the thermally-aged Fe-0.6 wt.% Cu alloy and compared the experimental result with that of the simulation by the FEFF simulation code in order to investigate the local atomic structure around Cu atoms. Cu precipitates which were produced by the thermal aging at 773 K transformed from the bcc structure to the fcc structure as the precipitates grow large enough. However, for electron-irradiated specimens, although the hardness greatly increased, the transformation of Cu precipitates from the bcc to the fcc structure was not clearly confirmed. This result indicates that small sized Cu precipitates which had the bcc structure were produced by the electron irradiation and they could hardly coarsen during the irradiation.

  16. Effects of Cu-doping on the magnetic state of Zn(0.9-x)Fe0.1Cu(x)O.

    Science.gov (United States)

    Ziq, Kh A; Ismail, A; Salem, A F; Ahmed, Shakeel; Ghannam, A

    2011-03-01

    Magnetization measurements were performed on a series of Zn(0.9-x)Fe0.1Cu(x)O samples (0 magnetization and enhances the hysteresis losses. Curie behavior of the susceptibility at high temperature indicates the presence of ferromagnetic exchange interaction. Moreover, we found that the exchange interaction and the molecular field coefficient are both ferromagnetic and greatly enhanced with Cu-doping; however, the Arrott-Belov-Kouvel plot did not reveal the presence of spontaneous magnetization down to 4.2 K.

  17. Impact of CrSiTi and NiSi on the Thermodynamics, Microstructure, and Properties of AlCoCuFe-Based High-Entropy Alloys

    Science.gov (United States)

    Wang, Xiao-Rong; Wang, Zhao-Qin; Lin, Tie-Song; He, Peng; Sekulic, Dusan P.

    2016-05-01

    Aiming to solve the problem of spontaneous combustion on titanium via electrospark deposition (ESD), two AlCoCuFe-based high-entropy alloys (HEAs), AlCoCuFe- x ( x = CrSiTi, NiSi), were produced by vacuum arc melting as electrodes in ESD process. The thermodynamic analysis of AlCoCuFe-based HEAs were carried out using the concept of mixing enthalpy matrix and a powerful thermodynamic calculation toolbox (HEA-Thermo-Calcu). The microstructure and mechanical properties of the two alloys were investigated. The AlCoCuFeCrSiTi alloy contains a body-centered cubic (BCC) phase and a face-centered cubic (FCC) phase. The AlCoCuFeNiSi alloy is composed of two BCC phases and an FCC phase. Addition of CrSiTi and NiSi to AlCoCuFe-based alloys makes the enthalpy of mixing to be sizably more negative than for the other AlCoCuFe-based HEAs. Notwithstanding the fact that the thermodynamic parameters do not agree with Yang's proposition, the two alloys form simple solid solutions. The electronegativity difference (Δ χ) favors a formation of the solid solution when Δχ ≤ 14.2. The hardness of AlCoCuFe- x ( x = CrSiTi, NiSi) alloys reaches 935 HV and 688 HV, respectively. The yield strength, fracture strength, and ultimate strain of AlCoCuFeNiSi are larger, i.e., 29, 30, and 45%, respectively, than those of the AlCoCuFeCrSiTi alloy.

  18. A new combined process for efficient removal of Cu(II) organic complexes from wastewater: Fe(III) displacement/UV degradation/alkaline precipitation.

    Science.gov (United States)

    Xu, Zhe; Gao, Guandao; Pan, Bingcai; Zhang, Weiming; Lv, Lu

    2015-12-15

    Efficient removal of heavy metals complexed with organic ligands from water is still an important but challenging task now. Herein, a novel combined process, i.e., Fe(III)-displacement/UV degradation/alkaline precipitation (abbreviated as Fe(III)/UV/OH) was developed to remove copper-organic complexes from synthetic solution and real electroplating effluent, and other processes including alkaline precipitation, Fe(III)/OH, UV/OH were employed for comparison. By using the Fe(III)/UV/OH process, some typical Cu(II) complexes, such as Cu(II)-ethylenediaminetetraacetic acid (EDTA), Cu(II)-nitrilotriacetic acid (NTA), Cu(II)-citrate, Cu(II)-tartrate, and Cu(II)-sorbate, each at 19.2 mg Cu/L initially, were efficiently removed from synthetic solution with the residual Cu below 1 mg/L. Simultaneously, 30-48% of total organic carbon was eliminated with exception of Cu(II)-sorbate. Comparatively, the efficiency of other processes was much lower than the Fe(III)/UV/OH process. With Cu(II)-citrate as the model complex, the optimal conditions for the combined process were obtained as: initial pH for Fe(III) displacement, 1.8-5.4; molar ratio of [Fe]/[Cu], 4:1; UV irradiation, 10 min; precipitation pH, 6.6-13. The mechanism responsible for the process involved the liberation of Cu(II) ions from organic complexes as a result of Fe(III) displacement, decarboxylation of Fe(III)-ligand complexes subjected to UV irradiation, and final coprecipitation of Cu(II) and Fe(II)/Fe(III) ions. Up to 338.1 mg/L of Cu(II) in the electroplating effluent could be efficiently removed by the process with the residual Cu(II) below 1 mg/L and the removal efficiency of ∼99.8%, whereas direct precipitation by using NaOH could only result in total Cu(II) removal of ∼8.6%. In addition, sunlight could take the place of UV to achieve similar removal efficiency with longer irradiation time (90 min).

  19. Multilayer epitaxial growth of lead phthalocyanine and C(70) using CuBr as a templating layer for enhancing the efficiency of organic photovoltaic cells.

    Science.gov (United States)

    Kim, Tae-Min; Shim, Hyun-Sub; Choi, Min-Soo; Kim, Hyo Jung; Kim, Jang-Joo

    2014-03-26

    The molecular orientation and crystallinity of donor and acceptor molecules are important for high-efficiency organic photovoltaic cells (OPVs) because they significantly influence both the absorption of light and charge-transport characteristics. We report that the templating effect extends to multilayers to increase the crystallinity and to modify the orientation of the crystals of lead phthalocyanine (PbPc) and C70 layers at the same time by adopting CuBr as a new templating layer on indium tin oxide (ITO). The formation of a monoclinic phase with a preferred orientation of (320) for PbPc and a fcc phase with a preferred orientation of (220) for C70 on the PbPc layer is revealed by X-ray diffraction (XRD) patterns. The multilayer epitaxy results in an increase of the exciton diffusion lengths from 5.6 to 8.8 nm for PbPc and from 6.9 to 13.8 nm for C70 to enhance the power conversion efficiency (PCE) of the planar heterojunction OPVs composed of PbPc and C70 from 1.4 to 2.3%. The quasi-epitaxy model is proposed to explain the multilayer epitaxy.

  20. Double negative electromagnetic properties of percolated Fe53Ni47/Cu granular composites

    Science.gov (United States)

    Tsutaoka, Takanori; Massango, Herieta; Kasagi, Teruhiro; Yamamoto, Shinichiro; Hatakeyama, Kenichi

    2016-05-01

    Electromagnetic properties of hybrid composite materials containing copper and permalloy (Fe53Ni47 alloy) particles have been investigated in the RF to microwave frequency range up to 20 GHz. Double negative permittivity and permeability spectra have been observed in the percolated state of the hybrid composite material. The negative permittivity spectra in this composite can be attributed to the low frequency plasmonic state produced by the percolated Cu and permalloy cluster chains as well as the dielectric resonance of the isolated metal clusters. The refractive index spectra which were calculated from the measured permittivity and permeability data indicated the negative refraction from 200 MHz to 1.8 GHz. The near zero or zero refractive index state can be obtained near the two zero crossing frequencies in the refractive index spectra.

  1. Sintered Fe-Ni-Cu-Sn-C Alloys Made of Ball-Milled Powders

    Directory of Open Access Journals (Sweden)

    Romański A.

    2014-10-01

    Full Text Available The main objective of this paper was to perform sinterability studies of ball-milled Fe-12%Ni-6.4%Cu-1.6%Sn-0.6%C powders. A mixture of precisely weighed amounts of elemental iron, nickel and graphite, and pre-alloyed 80/20 bronze powders was ball-milled for 8, 30 and 120 hours. After cold-pressing at 400 MPa the specimens were sintered at 900oC for 30 minutes in a reducing atmosphere and subsequently tested for density and hardness as well as subjected to structural studies using scanning electron microscopy (SEM and X-ray diffraction (XRD analysis.

  2. Domain wall pinning in FeCoCu bamboo-like nanowires

    Science.gov (United States)

    Berganza, Eider; Bran, Cristina; Jaafar, Miriam; Vázquez, Manuel; Asenjo, Agustina

    2016-07-01

    The three dimensional nature of cylindrical magnetic nanowires has opened a new way to control the domain configuration as well as the magnetization reversal process. The pinning effect of the periodic diameter modulations on the domain wall propagation in FeCoCu individual nanowires is determined by Magnetic Force Microscopy, MFM. A main bistable magnetic configuration is firstly concluded from MFM images characterized by the spin reversal between two nearly single domain states with opposite axial magnetization. Complementary micromagnetic simulations confirm a vortex mediated magnetization reversal process. A non-standard variable field MFM imaging procedure allows us to observe metastable magnetic states where the propagating domain wall is pinned at certain positions with enlarged diameter. Moreover, it is demonstrated that it is possible to control the position of the pinned domain walls by an external magnetic field.

  3. Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

    Energy Technology Data Exchange (ETDEWEB)

    Alves, M. J. P.; Gonzalez-Chavez, D. E.; Sommer, R. L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2015-03-28

    We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing.

  4. The content of Ca, Cu, Fe, Mg and Mn and antioxidant activity of green coffee brews.

    Science.gov (United States)

    Stelmach, Ewelina; Pohl, Pawel; Szymczycha-Madeja, Anna

    2015-09-01

    A simple and fast method of the analysis of green coffee infusions was developed to measure total concentrations of Ca, Cu, Fe, Mg and Mn by high resolution-continuum source flame atomic absorption spectrometry. The precision of the method was within 1-8%, while the accuracy was within -1% to 2%. The method was used to the analysis of infusions of twelve green coffees of different geographical origin. It was found that Ca and Mg were leached the easiest, i.e., on average 75% and 70%, respectively. As compared to the mug coffee preparation, the rate of the extraction of elements was increased when infusions were prepared using dripper or Turkish coffee preparation methods. Additionally, it was established that the antioxidant activity of green coffee infusions prepared using the mug coffee preparation was high, 75% on average, and positively correlated with the total content of phenolic compounds and the concentration of Ca in the brew.

  5. Effect of particle size on the exchange bias of Fe-doped CuO nanoparticles

    Science.gov (United States)

    Yin, S. Y.; Yuan, S. L.; Tian, Z. M.; Liu, L.; Wang, C. H.; Zheng, X. F.; Duan, H. N.; Huo, S. X.

    2010-02-01

    Effect of particle size on exchange bias in Fe-doped CuO nanoparticles is investigated, which are sintered at different temperatures from 350 to 650 °C, respectively. The structure and magnetic properties for different particle size samples were probed. It is found that the system shows magnetic properties transition from paramagnetic to ferromagnetic with increasing grain size, and exhibits the variations in exchange bias field (HEB) and coercivity (HC) at low temperature after field-cooled from 300 K. With the increase in the particles size, HEB decreases monotonously. Furthermore, vertical magnetization shift was also observed for the small particles. Exchange bias is attributed to the exchange coupling interactions between ferromagnetic and spin-glass-like (or antiferromagnetic) phase interface layers.

  6. Change in magnetic properties of a cold rolled and thermally aged Fe-Cu alloy

    Science.gov (United States)

    Park, D. G.; Ryu, K. S.; Kobayashi, S.; Takahashi, S.; Cheong, Y. M.

    2010-05-01

    The variation in magnetic properties of a Fe-1%Cu model alloy due to a cold rolling and a thermal aging has been evaluated to simulate the radiation damage of reactor pressure vessel of nuclear power plant. The thermal aging was conducted at 500 °C with different aging times in series. The hysteresis loops, magnetic Barkhausen noise (BN) and Vickers microhardness were measured for prestrained, strained, and thermal aged samples. The coercivity increased by a plastic strain and decreased by thermal aging, The BN decreased in the prestrained and strained samples but large changes were observed in the strained sample. These results were interpreted in terms of the domain wall motion signified by a change in the mean free path associated with microinternal stress and copper rich precipitates.

  7. Hydrogen absorption of NdDyFeCoNbCuB sintered magnets

    Institute of Scientific and Technical Information of China (English)

    LUO Jianjun; De Rango P; Fruchart D; MEI Jinna; HU Rui; LI Jinshan; ZHOU Lian

    2009-01-01

    Hydrogen absorption and desorption charactersfics for high coereivity NdDyFeCoNbCuB sintered bulk magnets were studied, by differential scanning calorimetry (DSC) measurement and hydrogenation kinetics measurement. The DSC measurements showed that hy-drogenation of Nd-rich phase occurred in the temperature range of 40-185 ℃, hydrogenation of the tetragonal (φ) phase in the temperature range of 185-220 ℃, as well as the disproportionation of the φ phase that occurred in a broad temperature range from around 500 to 800℃. The hydrogenation kinetics measurements indicated that hydrogen absorption of the bulk magnets at 50 ℃ absorbed more hydrogen than at 150 ℃, although this procedure was slower at 50 ℃ than at 150 ℃. This phenomenon was discussed by means of pres-sure-concentration-temperature (p-c-T) diagrams.

  8. Study of Fe2O3, CuO, ZnO catalyzed efficient Hantzsch reaction under different conditions

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Shushizadeh

    2015-05-01

    Full Text Available 1,4-dihydropyridine derivatives one-pot synthesis under different condition was described. CuO nanoparticle as a catalyst in microwave irradiation (100w gives product with excellent yields (≥87% and short reaction time. No significant difference was observed between the obtained yield by using ZnO and Fe2O3.

  9. Mossbauer studies of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy

    DEFF Research Database (Denmark)

    Jiang, Jianzhong

    1996-01-01

    This paper reports a Mossbauer study of amorphous Fe73.5Cu1Nb3Si13.5B9 alloy between 10 and 673 K. The Curie temperature Tc is found to be 620-+ 1 K. The temperature dependence of the reduced average hyperfine field can be explained on the basis of Handrich's model of amorphous ferromagnetism...

  10. Meta-analysis of Zn, Cu and Fe in the hair of Chinese children with recurrent respiratory tract infection.

    Science.gov (United States)

    Mao, Song; Zhang, Aihua; Huang, Songming

    2014-10-01

    Trace elements play an important role in maintaining the normal metabolic and immune function. The onset of recurrent respiratory tract infection (RRI) is associated with the immune function, genetic factors and nutritional status. However, the association between the levels of trace elements and RRI remains inconclusive. We aimed to investigate the alterations of hair levels of zinc (Zn), copper (Cu) and iron (Fe) in Chinese children with RRI by performing a meta-analysis. A predefined electronic databases search was performed to identify eligible studies for the analysis of hair Zn, Cu or Fe levels in Chinese children with RRI. Thirteen studies were included. RRI patients displayed significantly lower levels of hair Zn (13 studies, random effects SMD: - 1.215, 95% CI: - 1.704 to - 0.725, p < 0.0001), Cu (11 studies, random effects SMD: - 0.384, 95% CI: - 0.717 to - 0.052, p = 0.023) and Fe (12 studies, random effects SMD: - 0.569, 95% CI: - 0.827 to - 0.312, p < 0.0001) compared with controls. No evidence of publication bias was observed. Sensitivity analysis did not change the results significantly. In conclusion, the deficiency of Zn, Cu and Fe may be contributing factors for the susceptibility of RRI in Chinese children. However, more studies in different ethnicities should be performed in the future.

  11. Influence of quench rates on the properties of rapidly solidified FeNbCuSiB alloy

    Indian Academy of Sciences (India)

    A K Panda; I Chattoraj; S Basu; A Mitra

    2002-11-01

    FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques. The crystallization, magnetic, mechanical and corrosion behaviour were studied for the prepared materials as a function of quenching rate from liquid to the solid state. Higher quench rates produced a more amorphous structure exhibiting superior soft magnetic properties with improved corrosion resistance.

  12. Synthesis and structural, magnetic, and resonance properties of the LiCuFe2(VO4)3 compound

    Science.gov (United States)

    Drokina, T. V.; Petrakovskii, G. A.; Bayukov, O. A.; Vorotynov, A. M.; Velikanov, D. A.; Molokeev, M. S.

    2016-10-01

    Complex studies have been performed for the structural, static magnetic, and resonance properties of a new magnet LiCuFe2(VO4)3 prepared by solid-phase synthesis. The temperature dependence of the susceptibility has an anomaly at temperature T max = 9.6 K. At high temperatures, the LiCuFe2(VO4)3 sample is in the paramagnetic state described by the Curie-Weiss law at T > 50 K and mainly determined by iron ions with effective magnetic moment μeff(exp) = 8.6μB per formula unit. At low temperatures, a long-range magnetic order is observed in the magnetic subsystem of the sample; the order is predominantly characterized by the antiferromagnetic exchange interaction and high frustration level. The exchange interaction parameters are estimated in a six-sublattice representation of the LiCuFe2(VO4)3 magnet. It is shown that the LiCuFe2(VO4)3 compound is an antiferromagnet with strong intrachain and frustrating interchain exchange interactions.

  13. Iron atoms redistribution in oxide films of Zr-Fe, Zr-Fe-Cu alloys during corrosion in autoclave at 350°C

    Science.gov (United States)

    Filippov, V.; Bateev, A.

    2016-04-01

    The data on changes of iron atoms state in the oxide films of binary Zr-1.24 mas.%Fe and ternary Zr-1.39 mas.%Fe-0.60 mas.%Cu zirconium alloys are obtained. Alloys are subjected to corrosion tests under autoclave conditions at 350°C temperature in a steam-water environment under pressure p = 16.8 MPa. In initial specimens of the alloys the iron atoms are in the form of intermetallic compounds. In oxide films the decomposition of intermetallic compounds and formation of new compounds occurs with structural phase distortion. In the oxide films metallic the metallic iron particles α-Fe, iron oxide in the form of hematite α-Fe2O3, solid solutions of iron ions in ZrO2 are formed. The phase composition of the oxide films depends on the alloy composition and changes during the growth process of the oxide film.

  14. A study on atomic skips in AlFeCu perfect quasicrystals: application of the isotopic substitution method in neutron diffusion; Etude des sauts atomiques dans les quasicristaux parfaits AlFeCu: une application de la methode de substitution isotopique dans la diffusion des neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Coddens, G. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France); Soulie, E. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. de Recherche sur l`Etat Condense, les Atomes et les Molecules

    1994-12-31

    In order to better understand the crystal structure and the atomic skip or phason in quasi-crystals, three samples of the AlFeCu ternary alloy have been experimentally studied: Al{sub 62}Cu{sub 25.5}Fe{sub 12.5} (perfect sample), Al{sub 63}Cu{sub 24.5}Fe{sub 12.5} (non-perfect sample), Al{sub 50}Cu{sub 25}Fe{sub 25} (beta phase). Quasielastic neutron scattering variations with temperature and Q were recorded and signals have been enhanced through the use of isotope labelled samples. 4 figs., 2 tabs., 19 refs.

  15. Radical loss in the atmosphere from Cu-Fe redox coupling in aerosols

    Directory of Open Access Journals (Sweden)

    J. Mao

    2013-01-01

    Full Text Available The hydroperoxyl radical (HO2 is a major precursor of OH and tropospheric ozone. OH is the main atmospheric oxidant, while tropospheric ozone is an important surface pollutant and greenhouse gas. Standard gas-phase models for atmospheric chemistry tend to overestimate observed HO2 concentrations, and this has been tentatively attributed to heterogeneous uptake by aerosol particles. It is generally assumed that HO2 uptake by aerosol involves conversion to H2O2, but this is of limited efficacy as an HO2 sink because H2O2 can photolyze to regenerate OH and from there HO2. Joint atmospheric observations of HO2 and H2O2 suggest that HO2 uptake by aerosols may in fact not produce H2O2. Here we propose a catalytic mechanism involving coupling of the transition metal ions Cu(I/Cu(II and Fe(II/Fe(III to rapidly convert HO2 to H2O in aqueous aerosols. The implied HO2 uptake and conversion to H2O significantly affects global model predictions of tropospheric OH, ozone, carbon monoxide (CO and other species, improving comparisons to observations in the GEOS-Chem model. It represents a previously unrecognized positive radiative forcing of aerosols through the effects on the chemical budgets of major greenhouse gases including methane and hydrofluorocarbons (HFCs.

  16. Large magnetic anisotropy in strained Fe/Co multilayers on AuCu and the effect of carbon doping

    Directory of Open Access Journals (Sweden)

    G. Giannopoulos

    2015-04-01

    Full Text Available A tetragonally distorted FeCo structure is obtained in Fe/Co multilayers epitaxially grown on Au50Cu50 buffer using MgO single crystal substrates as a result of the lattice mismatch between the buffer and the FeCo ferromagnetic layer. The presence of large magnetic anisotropy energy (MAE of the order of 1 MJ/m3 has been confirmed by ferromagnetic resonance. Furthermore, the effect of carbon (C doping to maintain the tetragonal distortion throughout the thickness of 3 nm FeCo has been investigated. Our study shows that FeCo alloys maintain large magnetic moment and possess high MAE properties that are required for designing permanent magnets.

  17. Effect of Cu, Nb and Ta addition on the structural and magnetic properties of amorphous Fe-Si-B alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, A. E-mail: agupta@iucindore.ernet.inkane_sn@yahoo.com; Kane, S.N.; Bhagat, N.; Kulik, T

    2003-01-01

    The effect of successive additions of Cu, Nb and Ta in amorphous Fe{sub 77.5}Si{sub 13.5}B{sub 9} has been studied using X-ray diffraction and Moessbauer spectroscopy. Addition of Nb/Ta results in an increased near-neighbor distance as well as a decrease in topological order in the system. On the other hand, Cu addition results in a significant increase in the topological order. Addition of Cu does not significantly change the average hyperfine field, whereas, addition of Nb/Ta decreases the hyperfine field. Nb and Ta addition results in appearance of an additional hump in B{sub hf} around 13 T due to Fe atoms with Nb/Ta near neighbors. Thermal annealing of the specimens at 390 deg. C results in changes in the short-range order, which are mainly chemical in nature.

  18. Domain wall pinning sites in Sm(CoFeCuZr) x magnets

    Science.gov (United States)

    Wong, Bunsen Y.; Willard, Matthew; Laughlin, David E.

    1997-05-01

    The magnetic domain structure of Sm(CoFeCuZr) x magnets was studied along various crystallographic zone axes with high resolution Focault mode Lorentz microscopy. The domain wall has been observed to be pinned at (1) 60° hexagonal (H) SmCo 5 cell boundaries, (2) features parallel to RSm 2Co 17c-axis, (3) features parallel to the RSm 2Co 17 basal plane, and (4) linear features with no specific crystallographic direction. The wall pinning features which are parallel to the c-axis were determined to be RSm 2Co 17 antiphase boundaries (APB) and possibly vertical section of HSmCo 5 cell boundaries. Both these microstructure features were found to have a higher Cu content than the RSm 2Co 17 matrix. This chemical inhomogeneity leads to local variations in magnetocrystalline anisotropy assists domain wall pinning, similar to the role of HSmCo 5 suggested previously. Since not all the domain wall pinning features observed are in a strained state, this suggested that chemical segregation to nanostructural features such as HSmCo 5 cell boundaries and APB play a more important role than coherency strain in determining Hci.

  19. Domain wall pinning sites in Sm(CoFeCuZr){sub x} magnets

    Energy Technology Data Exchange (ETDEWEB)

    Wong, B.Y. [Pittsburgh Univ., PA (United States). Dept. of Materials Science and Engineering; Willard, M. [Pittsburgh Univ., PA (United States). Dept. of Materials Science and Engineering; Laughlin, D.E. [Pittsburgh Univ., PA (United States). Dept. of Materials Science and Engineering

    1997-05-01

    The magnetic domain structure of Sm(CoFeCuZr){sub x} magnets was studied along various crystallographic zone axes with high resolution Focault mode Lorentz microscopy. The domain wall has been observed to be pinned at (1) 60 hexagonal (H) SmCo{sub 5} cell boundaries, (2) features parallel to RSm{sub 2}Co{sub 17} c-axis, (3) features parallel to the RSm{sub 2}Co{sub 17} basal plane, and (4) linear features with no specific crystallographic direction. The wall pinning features which are parallel to the c-axis were determined to be RSm{sub 2}Co{sub 17} antiphase boundaries (APB) and possibly vertical section of HSmCo{sub 5} cell boundaries. Both these microstructure features were found to have a higher Cu content than the RSm{sub 2}Co{sub 17} matrix. This chemical inhomogeneity leads to local variations in magnetocrystalline anisotropy which assists domain wall pinning, similar to the role of HSmCo{sub 5} suggested previously. Since not all the domain wall pinning features observed are in a strained state, this suggested that chemical segregation to nanostructural features such as HSmCo{sub 5} cell boundaries and APB play a more important role than coherency strain in determining H{sub ci}. (orig.).

  20. 制备态Fe21Ni79/Cu/Fe21Ni79三明治薄膜的纵向巨磁阻抗效应%Longitudinal Giant Magneto-Impedance in As-deposited Fe21Ni79/Cu/Fe21Ni79 Sandwiched Films

    Institute of Scientific and Technical Information of China (English)

    商干兵; 周勇; 丁文; 余先育; 曹莹; 周志敏

    2006-01-01

    采用直流电镀结合正胶光刻工艺制备了Fe21Ni79/Cu/ Fe21Ni79三明治薄膜,并在0.1~40MHz范围内研究了它的纵向巨磁阻抗效应特性.实验结果表明,Fe21Ni79/Cu/ Fe21Ni79三明治薄膜有十分明显的纵向GMI效应,GMI先随外加磁场的增高而迅速增大,在Hext=0.96kA/m达到最大值后开始逐渐下降.在频率为1.2MHz,外加磁场为0.96kA/m时薄膜的纵向GMI最大值达到88.3%.

  1. Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2014-09-01

    Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

  2. Microstructure Evolution in a Rapidly Solidified Cu85Fe15 Alloy Undercooled into the Metastable Miscibility Gap

    Institute of Scientific and Technical Information of China (English)

    Jie HE; Jiuzhou ZHAO

    2005-01-01

    A model has been developed to describe the microstructure evolution in the atomized droplets of Cu-Fe alloy during cooling through the metastable miscibility gap. Calculations have been performed for Cu85Fe15 alloy to investigate the process of liquid-liquid phase transformation. The numerical results indicate that the minority phase droplets are nucleated in a temperature region around the peak of the supersaturation. The average radius of the Fe-rich droplets decreases and the number density of the minority phase droplets increases with decreasing the atomized droplet size.The simulated results were compared with the experimental ones. The kinetic process of the liquid-liquid phase transformation was discussed in detail.

  3. Ferromagnetic Fe on Cu(001) throughout the fcc-like phase: arguing from the viewpoint of the electronic structure.

    Science.gov (United States)

    Donath, M; Pickel, M; Schmidt, A B; Weinelt, M

    2009-04-01

    The scientific enthusiasm for ultrathin Fe films on Cu(001) has now lasted for more than 20 years. Is there ferromagnetic iron with a face-centred cubic (fcc) structure? Does ferromagnetism in Fe hinge on the body-centred cubic (bcc) structure? In this contribution, we try to establish that the electron system gives evidence of ferromagnetic behaviour with fcc-like electronic bands. We examine a crystal-induced surface state, which is characteristic of fcc surface order. Furthermore, we compare electronic signatures of fcc and bcc: the d-band exchange splitting, image-potential-state energies and the work function. We conclude that, from the viewpoint of the electronic structure, Fe on Cu(001) is found to be ferromagnetic throughout the fcc-like phase. This result raises a new question: how much deviation from the relaxed fcc order is acceptable without losing the electronic signature of fcc?

  4. Mechanical properties of FeCo magnetic particles-based Sn-Ag-Cu solder composites

    Science.gov (United States)

    Xu, Siyang; Prasitthipayong, Anya; Pickel, Andrea D.; Habib, Ashfaque H.; McHenry, Michael E.

    2013-06-01

    We demonstrate magnetic nanoparticles (MNPs) in enabling lead-free solder reflow in RF fields and improved mechanical properties that impact solder joint reliability. Here, we report on Sn-Ag-Cu (SAC) alloys. SAC solder-FeCo MNP composites with 0, 1, 2, 3, and 4 wt. % FeCo MNP and the use of AC magnetic fields to achieve localized reflow. Electron microscopy of the as-reflowed samples show a decrease in the volume of Sn dendrite regions as well as smaller and more homogeneously dispersed Ag3Sn intermetallic compounds (IMCs) with increasing MNP concentrations. Mechanical properties of the composites were measured by nanoindentation. In pure solder samples and solder composites with 4 wt. % MNP, hardness values increased from 0.18 GPa to 0.20 GPa and the modulus increased from 39.22 GPa to 71.22 GPa. The stress exponent, reflecting creep resistance, increased from 12.85 of pure solder to 16.47 for solder composites with 4 wt. % MNP. Enhanced mechanical properties as compared with the as-prepared solder joints are explained in terms of grain boundary and dispersion strengthening resulting from the microstructural refinement.

  5. Magnetic properties of (Zn,Cd,Cu)-Co-Fe-Ti spinel oxides

    Energy Technology Data Exchange (ETDEWEB)

    Moyo, T.; Giordanengo, B.; Melo, M.A.C. de; Takeuchi, A.Y.; Silva, P.R.J.; Saitovitch, H.; Baggio-Saitovitch, E. [University of Natal, Department of Physics (South Africa)

    1999-09-15

    AC susceptibility, magnetization and Moessbauer spectra have been measured for (Zn,Cd,Cu){sup 0.5}Co{sub 0.9}Fe{sub 1.2}Ti{sub 0.4}O{sub 4} and Zn{sub 0.3}Co{sub 0.9}Fe{sub 1.4}Ti{sub 0.4}O{sub 4} spinel oxides. The variation of coercive field below the spin glass transition temperature T{sub sg} is found to fit a double exponential function of the form H{sub c}(T)=H{sub 1e}{sup -{beta}{sub 1}}{sup T}+H{sub 2e}{sup -{beta}{sub 2}}{sup T}, where H{sub i} and {beta}{sub i} are constants. Moessbauer spectra and analysis show superparamagnetic fluctuations associated with magnetic clusters. Symmetric doublets above T{sub sg} are decomposed into quadrupole doublets associated with tetrahedral (A) and octahedral (B) sites.

  6. Study of the behaviour of the dielectric constant in Cu, Fe: BaTiO3

    Institute of Scientific and Technical Information of China (English)

    Alioune OUEDRAOGO; Kalifa PALM; Issaka OUEDRAOGO; Guy CHANUSSOT

    2008-01-01

    In this work we study the behaviour of the dielectric constant of BaTiO3 single crystals doped with Cu and Fe for different ion percentages, particularly, the influence of these heterovalent substitutions on the ferroelectric-paraelectric phase transition whose temperature is found at Tc=120 ℃ for pure samples. The dielectric constant ε in terms of temperature shows that the Curie temperature decreases when the quantity of impurities increases and presents a broadening and flattering of the maximum of ε(T) within higher values, with the transition becoming more and more diffuse. It is interesting to have a material with very high permittivity (high-k) because of its capacity to store an important quantity of electric charges. The ε anisotropy and the Curie-Weiss law are also verified with a good ratio between the slopes ofε-1(T) from both sides of the transition, leading to a Curie constant: C= 13×104 K for BaTiO3:1.6%Fe in the polar phase. BaTiO3 is a displacive ferroelectric going through a first-order phase transition. The substitutions have an effect on the dynamics of the perovskite lattice. They induce charges transfer to Ti and a diminution of elastic forces in BaTiO3. Then we discuss the fact that the maximum of permittivity does not depend on the phase transition but on the nature of the material.

  7. Effects of Fe-deficiency on magnetic properties and Brillouin function characteristics for NiCuZn ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Linglong; Yu, Zhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yang, Yan [Department of Communication Engineering, Chengdu Technological University, Chengdu 611730 (China); Guo, Rongdi; Jiang, Xiaona; Sun, Ke; Wu, Chuanjian; Lan, Zhongwen [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2015-08-01

    The polycrystalline Ni{sub 0.56}Cu{sub 0.10}Zn{sub 0.34}Fe{sub 2−x}O{sub 4−3/2x} (x=0.00~0.14) ferrites have been prepared by conventional oxide ceramics process. The effects of Fe-deficiency content on magnetic properties and Brillouin function characteristics for NiCuZn ferrites have been investigated in details. With the increase of Fe-deficiency content, the opposite variation trend are observed for the saturation magntic induction B{sub s} and the coercivity H{sub c}. More importantly, based on the Néel molecular field theory, for the spinel ferrites which do not only contain Fe{sup 3+} but also some other multiple magnetic ions (Ni{sup 2+} and Cu{sup 2+}), the molecular field coefficients ω{sub aa}, ω{sub bb} and ω{sub ab=}ω{sub ba} are calculated by non-linear fitting method, and the Curie temperature T{sub c} formula has been modified. With the increase of Fe-deficiency content, the values of ω{sub aa} and ω{sub bb} increase gradually, however, the value of ω{sub ab}=ω{sub ba} has a contrary trend which results in the decrease of the Curie temperature. In addition, the fitting Curie temperatures values are coincided well with the Curie temperatures calculated by the modified formula. - Highlights: • Néel molecular field theory model of multi-magnetic ions (Fe{sup 3+}, Ni{sup 2+}, Cu{sup 2+}) is completed and the correlation formula of Curie temperature has been derived. • The calculating for the molecular field coefficients has been completed from absolute zero degree to Curie temperature. • The corresponding values and variation trend of molecular field coefficients have been completely investigated.

  8. NdFeB磁性材料表面化学镀Ni-Cu-P实验研究%Electroless plating of Ni-Cu-P alloy on the surface of NdFeB permanent magnets

    Institute of Scientific and Technical Information of China (English)

    王憨鹰; 李增生; 李成荣; 陈焕铭

    2011-01-01

    In order to improve corrosion resistance of electroless plating Ni-Cu-P coating, plating bath and plating parameters of eletroless deposition of Ni-Cu-P alloy on the surface of NdFeB magnets was optimized by an orthogonal experiment. The optimal formula of electroless Ni-Cu-P plating bath was obtained as follows: 25 g/L of nickel sulfate, 0.4 g/L of copper sulfate, 35 g/L of sodium hypophosphite, 48 g/L of complexant, 50 g/L of buffering agent and pH value of 9. The effect of pH and CuSO4 ? 5H2O content in solution on plating rate and deposit composition was investigated. It is found that the plating rate and the copper and nickel contents of the deposit increase with increasing pH, while phosphorus content decreases; with increasing CuSO4?5H2O content in solution, the copper content of the deposit increases, while the phosphorus contents first increase and then decrease with a simultaneous decrease in the nickel content.%为提高Ni-Cu-P合金镀层的耐腐蚀性,采用正交试验法对NdFeB磁体表面化学镀Ni-Cu-P合金的镀液配方和施镀工艺进行优化,获得NdFeB磁体表面化学镀Ni-Cu-P合金的最佳成分配方为:硫酸镍25g/L,硫酸铜0.4 g/L,次亚磷酸钠35 g/L,络合剂48 g/L,缓冲剂50 g/L,pH值9.分析镀液pH值和镀液中CuS04·5H20浓度对沉积速度和镀层成分的影响.结果表明:随镀液pH值增加,沉积速度提高,镀层中Cu和Ni含量略升高,P含量逐渐降低;随镀液中CuS04·5H20浓度的增加,镀层中Cu含量升高,P含量先升高后降低,Ni含量降低.

  9. Heterotrimetallic coordination polymers: {Cu(II)Ln(III)Fe(III)} chains and {Ni(II)Ln(III)Fe(III)} layers: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Alexandru, Maria-Gabriela; Visinescu, Diana; Andruh, Marius; Marino, Nadia; Armentano, Donatella; Cano, Joan; Lloret, Francesc; Julve, Miguel

    2015-03-27

    The use of the [Fe(III) (AA)(CN)4](-) complex anion as metalloligand towards the preformed [Cu(II) (valpn)Ln(III)](3+) or [Ni(II) (valpn)Ln(III) ](3+) heterometallic complex cations (AA=2,2'-bipyridine (bipy) and 1,10-phenathroline (phen); H2 valpn=1,3-propanediyl-bis(2-iminomethylene-6-methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu(II) (valpn)Ln(III) (H2O)3 (μ-NC)2 Fe(III) (phen)(CN)2 {(μ-NC)Fe(III) (phen)(CN)3}]NO3 ⋅7 H2O}n (Ln=Gd (1), Tb (2), and Dy (3)) and the trinuclear complex [Cu(II) (valpn)La(III) (OH2 )3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ]⋅NO3 ⋅H2O⋅CH3 CN (4) were obtained with the [Cu(II) (valpn)Ln(III)](3+) assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni(II) (valpn)Ln(III) (ONO2 )2 (H2 O)(μ-NC)3 Fe(III) (bipy)(CN)]⋅2 H2 O⋅2 CH3 CN}n (Ln=Gd (5), Tb (6), and Dy (7)) resulted with the related [Ni(II) (valpn)Ln(III) ](3+) precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu(II) (valpn)La(III) (OH2)3 (O2 NO)(μ-NC)Fe(III) (phen)(CN)3 ](+), nitrate counterions, and non-coordinate water and acetonitrile molecules. The heteroleptic {Fe(III) (bipy)(CN)4} moiety in 5-7 acts as a tris-monodentate ligand towards three {Ni(II) (valpn)Ln(III)} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu(II)-Ln(III) (1-3) and Ni(II)-Ln(III) (5-7) units, as well as through the single cyanide bridge between the Fe(III) and either Ni(II) (5-7) or Cu(II) (4) account for the overall ferromagnetic behavior observed in 1-7. DFT-type calculations were performed to substantiate the magnetic interactions in 1, 4, and 5. Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out-of-phase ac signals below 4.0 K in the lack of a dc field, the values of the pre

  10. Synthesis and characterization of the 1.1 adducts of copper(I) halides with bidentate N,N′-bis(benzophenone)-1,2-diiminoethane Schiff base: Crystal structures of [Cu(bz2en)2][CuX2] (X = Br, I) complexes

    NARCIS (Netherlands)

    Kia, Reza; Mirkhani, Valiollah; Harkema, Sybolt; Hummel, van Gerrit J.

    2007-01-01

    1:1 adducts of N,N′-bis(benzophenone)-1,2-diiminoethane (bz2en) with copper(I) chloride, bromide and iodide, [Cu(bz2en)2][CuX2] (X = Cl, Br, and I), have been synthesized and the structures of the solid bromide and iodide adducts were determined by X-ray crystallography from single-crystal data. The

  11. Magnetoimpedance effect of the Ni80Fe20/Cu composite wires: The influence of DC current imposed on the Cu base

    Directory of Open Access Journals (Sweden)

    Delu Chen

    2014-06-01

    Full Text Available In this paper, the copper composite wires of 75 μm in diameter with a sputtered layer of Ni80Fe20 permalloy were prepared, with a DC current applied to the basal Cu terminals during the fabrication process. The influence of the DC current on the magnetic configuration and Magneto-Impedance (MI effect was studied. The results indicate that both the current amplitude and actuation duration have significant effect on the magnetic properties of the Ni80Fe20 layer. With appropriate current applied, the induced magnetic field leads to a circumferential magnetic domain structure and reduces significantly the equivalent anisotropy field of Ni80Fe20 layer. Then, the GMI ratio of the composite wires was significantly increased. A maximum GMI of 194.8% can be reached when the current was fixed at 100 mA and the Ni80Fe20 thickness is 780 nm. If the Ni80Fe20 thickness is above 780 nm, the coercivity of the coating layer increases while the GMI ratio of the composite wire reduces, since the magnetic anisotropy of the Ni80Fe20 layer varies from circumferential to longitudinal. The results were explained combining the thermal and magnetic effects of current.

  12. Preparation of polypyrrole-coated CuFe2O4 and their improved electrochemical performance as lithium-ion anodes

    Institute of Scientific and Technical Information of China (English)

    Huayun Xu; Yunpo Wang; Long Zheng; Xinhui Duan; Lihui Wang; Jian Yang; Yitai Qian

    2014-01-01

    CuFe2O4 network, prepared via the electrostatic spray deposition technique, with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported. The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole (PPy). At the current density of 100 mA·g-1, Li/CuFe2O4 electrode delivers a reversible capacity of 842.9 mAh·g-1 while the reversible capac-ity of Li/PPy-coated CuFe2O4 electrode increases up to 1106.7 mAh·g-1. A high capacity of 640.7 mAh·g-1 for the Li/PPy-coated CuFe2O4 electrode is maintained in contrast of 398.9 mAh·g-1 for Li/CuFe2O4 electrode after 60 cycles, which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity. The electrochemical impedance spectroscopy (EIS) further reveals that the Li/PPy-coated CuFe2O4 electrode has a lower charge transfer resistance than the Li/CuFe2O4 electrode.

  13. Effect of Element Cobalt on Microstructure and Properties of AlFeCuCrNi High Entropy Alloys%钴对AlFeCuCrNi高熵合金组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    朱海云; 孙宏飞; 高绪

    2013-01-01

    AlFeCuCrNiCo, (χ=0, 0. 5, 1. 0) high entropy alloys were prepared by vacuum arc furnace. The microstructure and phase structure change of AlFeCuCrNi alloys after addition of element cobalt were investigated by ()M, SEM, EMP, XRD and TEM. And hardness, thermal stability and corrosion resistance of these alloys were also studied. The results show the microstructure of AlFeCuCrNiCo., alloys was typically dendritic structure, the phases of these alloys consisted of simple face-centered cubic (FCC) and body-centered cubic (BCC), and adding of element cobalt reduced the lattice constants both of FCC and BCC. Compositions segregation existed in all alloys, and addition of element cobalt promoted segregation of element copper and homogenization of all the other elements. The hardness and corrosion resistance of the alloys were increased after addition of element cobalt and all alloys possessed good thermal stability.%采用真空电弧熔炼技术制备了AlFeCuCrNiCox(x=0,0.5,1.0)合金体系,通过光学显微镜、扫描电镜、电子探针、X射线衍射仪以及透射电镜研究了在AlFeCuCrNi合金中加入钴元素后显微组织及结构的变化,并对合金系的显微硬度、热稳定性及耐腐蚀性进行了研究.结果表明:AlFeCuCrNiCox(x=0,0.5,1.0)合金的显微组织均为树枝晶;合金的物相组成均为简单的体心立方和面心立方的混合结构,钴元素的加入会使合金中体心立方和面心立方的晶格常数均有所减小;所有合金均存在成分偏析现象,钴元素的加入加剧了合金中铜元素的偏析,但促进了其他元素的均匀化;钴元素的加入使合金显微硬度提高,耐腐蚀性增加;所有合金均具有较好的热稳定性.

  14. Study on the covalence of Cu and chemical bonding in an inorganic fullerene-like molecule, [CuCl]20[Cp*FeP5]12[Cu-(CH3CN)2+Cl-]5, by a density functional approach

    Institute of Scientific and Technical Information of China (English)

    WANG Bingwu; XU Guangxian; CHEN Zhida

    2004-01-01

    The electronic structure and chemical bonding in a recently synthesized inorganic fullerene-like molecule, {[CuCl]20[Cp*FeP5]12 [Cu(CH3CN)+2Cl-]5}, has been studied by a density functional approach. Geometrical optimization of the three basic structural units of the molecule is performed with Amsterdam Density Functional Program. The results are in agreement with the experiment. Localized MO's obtained by Boys-Foster method give a clear picture of the chemical bonding in this molecule. The reason why CuCl can react with Cp*FeP5 in solvent CH3CN to form the fullerene-like molecule is explained in terms of the soft-hard Lewis acid base theory and a new concept of covalence.

  15. Effect of component substitution on the microstructure and mechanical properties of MCoCrFeNiTix (M = Cu,Al) solid-solution alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    MCoCrFeNiTix (M = Cu,Al;x:molar ratio,x = 0,0.5) alloys were prepared using the new alloy-design strategy of equal-atomic ratio and high entropy.By the component substitution of Al for Cu,the microstructure changes from the face-centered cubic solid solution of original CuCoCrFeNiTix alloys to the body-centered cubic solid solution of AICoCrFeNiTix alloys.Compared with original CuCoCrFeNiTix alloys,AICoCrFeNiTix alloys keep the similar good ductility and simultaneously possess a much higher compressive strength,which are even superior to most of the reported high-strength alloys like bulk metallic glasses.

  16. Spin polarized low energy electron microscopy of quantum well resonances in Fe films on the Cu-covered W(110) surface.

    Science.gov (United States)

    Wu, Qiang; Altman, M S

    2013-07-01

    Spin polarized low energy electron microscopy has been used to investigate the quantum size effect (QSE) in electron reflectivity from Fe films grown on a pseudomorphic Cu layer on a W(110) surface. Intensity oscillations caused by the QSE as functions of Fe film thickness and incident electron energy identify quantum well resonance conditions in the film. Evaluation of these intensity oscillations using the phase accumulation model provides information on the unoccupied spin polarized band structure in the Fe film above the vacuum level. We also find evidence that the presence of the non-magnetic Cu layer shifts spin polarized quantum well resonances in the Fe layer uniformly downward in energy by 1.1eV compared to Fe/W(110) films without an interface Cu layer, suggesting that the Cu layer gives a small degree of control over the quantum well resonances.

  17. Structure properties of nanostructured Fe films grown on c(2 x 2) N/Cu(1 0 0) self-organised surface

    Energy Technology Data Exchange (ETDEWEB)

    Finetti, P.; Borgatti, F.; Felici, R.; Gunnella, R.; D' Addato, S

    2003-05-15

    The growth of Fe on the c(2x2) N/Cu(1 0 0) surface was studied with X-ray absorption fine structure (XAFS) assisted by LEED. Previous STM work had shown that atomic N on Cu(1 0 0) forms periodic arrays of c(2x2) N islands with a size of about 5 nmx5 nm channelling the growth of Fe onto the clean Cu areas. From XAFS multishell analysis we describe the growth in terms of face-centred cubic (fcc) phase with strong lattice distortion, deviation from layer by layer growth, and presence of complex surface phases, some with different geometry. The differences between the Fe growth mode on the clean and on the N-saturated Cu(1 0 0) surface are explained in terms of Fe-N atom interactions, and we obtained the adsorption geometry of Fe on the N-saturated surface.

  18. Nanostructured Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode for efficient hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Dipika; Upadhyay, Sumant; Verma, Anuradha [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Satsangi, Vibha R. [Department of Physics Computer Sciences, Dayalbagh Educational Institute, Agra-282 110 India (India); Shrivastav, Rohit [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India); Dass, Sahab, E-mail: drsahabdas@gmail.com [Department of Chemistry, Dayalbagh Educational Institute, Agra-282 110 India (India)

    2015-01-01

    Nanostructured thin films of pristine Fe{sub 2}O{sub 3}, Ti-doped Fe{sub 2}O{sub 3}, Cu{sub 2}O, and Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-doped Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction were deposited on tin-doped indium oxide (Sn:In{sub 2}O{sub 3}) glass substrate using spray pyrolysis method. Ti doping is done to improve photoelectric conversion efficiency and electrical conductivity of hematite thin films. Further enhanced photocurrent is achieved for Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction electrodes. All samples were characterized using X-ray diffractometry, scanning electron microscopy, atomic force microscopy, and UV-Vis spectrometry. Photoelectrochemical properties were also investigated in a three-electrode cell system. UV-Vis absorption spectrum for pristine Fe{sub 2}O{sub 3}, Ti-Fe{sub 2}O{sub 3}, Cu{sub 2}O, Fe{sub 2}O{sub 3}/Cu{sub 2}O, and Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction thin films exhibited absorption in visible region. Nanostructured thin films as prepared were used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 2.60 mA/cm{sup 2} at 0.95 V/SCE was exhibited by 454 nm thick Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction photoelectrode. Increased photocurrent density and enhanced incident photon-to-electron conversion efficiency, offered by the heterojunction thin films may be attributed to improved conductivity and efficient separation of the photogenerated charge carriers at the Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O interface. - Highlights: • Heterojunction thin films were deposited using spray pyrolysis techniques. • Titanium doping in Fe{sub 2}O{sub 3} played a significant role in PEC response. • Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O heterojunction shows the absorption in visible range. • Improved charge separation and enhanced PEC response were achieved in Ti-Fe{sub 2}O{sub 3}/Cu{sub 2}O.

  19. Highly Efficient Synthesis of 1,2,3-Triazoles Catalyzed by Silane Coupled Chitosan-CuBr Catalyst%硅烷偶联化壳聚糖负载CuBr高活性催化合成1,2,3-三唑化合物

    Institute of Scientific and Technical Information of China (English)

    江云兵; 王彦龙; 韩骞; 朱荣俊; 熊兴泉

    2014-01-01

    N-(2-Aminoethyl)-3-aminopropyltriethoxysilane-modified chitosan (CS-AAPTS) was successfully prepared by simply refluxing the corresponding CS and AAPTS in toluene solution. Subsequently, CS-AAPTS bound CuBr (CS-CuBr) was synthesized by the reaction of CS-AAPTS with CuBr in DMF at room temperature under N2 atmosphere. The obtained catalyst was characterized by FT-IR, TGA, XRD and EDX. The catalytic performances were evaluated in one-pot multicom-ponent copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction under microwave-assisted condition. CS-CuBr was found to exhibit obvious catalytic activity to rapidly prepare 1,2,3-triazole compounds under the microwave irradiation power of 480 W and 70 ℃ operating conditions. Furthermore, the catalyst could be easily recovered by simple filtration and recy-cled at least 4 cycles without significant loss of activity, and the preparation of 1,2,3-triazoles could be scaled up to multi-ple-gram conveniently with a yield up to 94%.%以壳聚糖为原料,将其与 N-(2-氨乙基)-3-氨丙基三乙氧基硅烷(AAPTS)反应制得胺基功能化的壳聚糖(CS-AAPTS),然后将CS-AAPTS与CuBr进行络合制备得到负载型催化剂(CS-CuBr)。通过FT-IR, TGA, XRD以及EDX等分析方法对CS-CuBr催化剂进行表征。结合微波辐射技术以及“一锅法”合成策略,以CS-CuBr为催化剂催化有机炔、卤代烷以及NaN3之间的环加成反应制备1,2,3-三唑。结果表明, CS-CuBr具有良好的催化性能,微波辐射功率为480 W,温度为70℃条件下,可快速合成出1,2,3-三唑类化合物。 CS-CuBr易回收和重复使用,重复使用4次后仍可保持良好收率。初步放大实验表明,1,2,3-三唑类化合物能够以94%的收率以十数克规模制备。

  20. Hyperfine interaction and tuning of magnetic anisotropy of Cu doped CoFe2O4 ferrite nanoparticles

    Science.gov (United States)

    Batoo, Khalid Mujasam; Salah, Dina; Kumar, Gagan; Kumar, Arun; Singh, Mahavir; Abd El-sadek, M.; Mir, Feroz Ahmad; Imran, Ahamad; Jameel, Daler Adil

    2016-08-01

    Ferrimagnetic oxides may contain single or multi domain particles which get converted into superparamagnetic state near a critical size. To explore the existence of these particles, we have made Mössbauer and magnetic studies of Cu2+ substitution effect in CoFe2-xO4 Ferrites (0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). All the samples have a cubic spinel structure with lattice parameters increasing linearly with increase in Cu content. The hysteresis loops yield a saturation magnetization, coercive field, and remanent magnetization that vary significantly with Cu content. The magnetic hysteresis curves shows a reduction in saturation magnetization and an increase in coercitivity with Cu2+ ion substitution. The anisotropy constant, K1, is found strongly dependent on the composition of Cu2+ ions. The variation of saturation magnetization with increasing Cu2+ ion content has been explained in the light of Neel's molecular field theory. Mössbauer spectra at room temperature shows two ferrimagnetically relaxed Zeeman sextets. The dependence of Mössbauer parameters such as isomer shift, quadrupole splitting, line width and hyperfine magnetic field on Cu2+ ion concentration have been discussed.

  1. Competing magnetic ground states and their coupling to the crystal lattice in CuFe2Ge2

    Science.gov (United States)

    May, Andrew F.; Calder, Stuart; Parker, David S.; Sales, Brian C.; McGuire, Michael A.

    2016-01-01

    Identifying and characterizing systems with coupled and competing interactions is central to the development of physical models that can accurately describe and predict emergent behavior in condensed matter systems. This work demonstrates that the metallic compound CuFe2Ge2 has competing magnetic ground states, which are shown to be strongly coupled to the lattice and easily manipulated using temperature and applied magnetic fields. Temperature-dependent magnetization M measurements reveal a ferromagnetic-like onset at 228 (1) K and a broad maximum in M near 180 K. Powder neutron diffraction confirms antiferromagnetic ordering below TN ≈ 175 K, and an incommensurate spin density wave is observed below ≈125 K. Coupled with the small refined moments (0.5–1 μB/Fe), this provides a picture of itinerant magnetism in CuFe2Ge2. The neutron diffraction data also reveal a coexistence of two magnetic phases that further highlights the near-degeneracy of various magnetic states. These results demonstrate that the ground state in CuFe2Ge2 can be easily manipulated by external forces, making it of particular interest for doping, pressure, and further theoretical studies. PMID:27739477

  2. Determination of some heavy metals (Fe, Cu, Zn and Pb) in blood by total reflection X-ray fluorescence

    Science.gov (United States)

    Bounakhla, M.; Doukkali, A.; Lalaoui, K.; Aguenaou, H.; Mokhtar, N.; Attrassi, B.

    2003-05-01

    The main purpose of this study is the interaction between nutrition (micronutrients heavy metals: Fe, Zn, Cu) and toxic heavy metals such as Pb in blood of children living in Gharb region of Morocco. This region receives all pollution carried by the Sebou river coming mainly from industrial activities. A rapid and simple analytical procedure was used for the determination of Fe, Cu and Zn trace amounts in blood by total-reflection X-ray fluorescence technique. This method is an energy dispersive XRF technique in a special geometry of primary beam, sample and detector. The sample is deposited on a plane polished surface of a suitable reflector material. It is presented as a few drops (25 μl) from a solution of blood digested in a mixture of HNO3 and H2O2 using a microwaves accelerated reaction system. The accuracy of measurements has been investigated by using certified materials. The concentration of Cu was found to be normal in all samples (\\cong1 ppm) which ruled out any interaction between this element and the others. On the other hand, amounts of Fe and Zn are very variables, suggesting an interaction between Fe and Zn. However, amounts of Pb in blood are inferior to 50 ppb, suggesting that no interaction exist with this metal and micronutrients.

  3. Dye-Sensitized Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) Nanofibers for Efficient Photocatalytic Hydrogen Evolution.

    Science.gov (United States)

    Gonce, Mehmet Kerem; Aslan, Emre; Ozel, Faruk; Hatay Patir, Imren

    2016-03-21

    The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1) h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4, Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light.

  4. Influence of leaching on surface composition, microstructure, and valence band of single grain icosahedral Al-Cu-Fe quasicrystal

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, M.; McGrath, R.; Sharma, H. R. [Surface Science Research Centre and The Department of Physics, The University of Liverpool, Liverpool L69 3BX (United Kingdom); Yadav, T. P. [Hydrogen Energy Centre, Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Fournée, V.; Ledieu, J. [Institut Jean Lamour (UMR7198 CNRS-Université de Lorraine), Parc de Saurupt, 54011 Nancy Cedex (France)

    2015-03-07

    The use of quasicrystals as precursors to catalysts for the steam reforming of methanol is potentially one of the most important applications of these new materials. To develop application as a technology requires a detailed understanding of the microscopic behavior of the catalyst. Here, we report the effect of leaching treatments on the surface microstructure, chemical composition, and valence band of the icosahedral (i-) Al-Cu-Fe quasicrystal in an attempt to prepare a model catalyst. The high symmetry fivefold surface of a single grain i-Al-Cu-Fe quasicrystal was leached with NaOH solution for varying times, and the resulting surface was characterized by x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The leaching treatments preferentially remove Al producing a capping layer consisting of Fe and Cu oxides. The subsurface layer contains elemental Fe and Cu in addition to the oxides. The quasicrystalline bulk structure beneath remains unchanged. The subsurface gradually becomes Fe{sub 3}O{sub 4} rich with increasing leaching time. The surface after leaching exhibits micron sized dodecahedral cavities due to preferential leaching along the fivefold axis. Nanoparticles of the transition metals and their oxides are precipitated on the surface after leaching. The size of the nanoparticles is estimated by high resolution transmission microscopy to be 5-20 nm, which is in agreement with the AFM results. Selected area electron diffraction (SAED) confirms the crystalline nature of the nanoparticles. SAED further reveals the formation of an interface between the high atomic density lattice planes of nanoparticles and the quasicrystal. These results provide an important insight into the preparation of model catalysts of nanoparticles for steam reforming of methanol.

  5. Effects of magnetic field orientation and injected current density on the output of nano-structured Co/Cu/Fe junctions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Co/Cu/Fe nano-sized sandwich thin films have been prepared by electron beam evaporation. 5 μm×5 μm Co/Cu/Fe sandwich heterojunction was made using photolithography and lift-off process. The bipolar output signal of Co/Cu/Fe junctions has been measured and analyzed. The effects of applied magnetic field angle (referring to the normal of the junction plane) and injecting spin-polarized current on the output signals have been studied, and the measured results were discussed.

  6. ENHANCEMENT OF BOTH IONIC CONDUCTIVITY AND PERMITTIVITY OF THE HIGH POLYMER FILM P(EO)n-CuBr2 UNDER HYDROSTATIC PRESSURE (Ⅰ) —Discovery of Pressure Effects of Three Different Phases%高聚物P(EO)n-CuBr2薄膜在流体静高压下离子 电导率和介电常数的提高(Ⅰ) 发现三种不同相的压力效应

    Institute of Scientific and Technical Information of China (English)

    苏骁; 戴卫平; 苏日方

    2001-01-01

    With the addition of different weight of CuBr2(ratio n=[EO]/[Cu]=4,8,12,16,24)to polyethylene oxide(molecular weight 5×106),a series of high polymer ionic conductors P(EO)n-CuBr2 were prepared.Both complex impedance spectra of samples in the hydrostatic pressure range from 0.1 to 350MPa and alternating current conductivity of samples in the pressure range from 0.1 to 2400MPa were measured in detail.Results show that the pressure dependence of conductivity can be decomposed into four linear parts.According to the phase analysis from X-ray diffraction patterns,it is found that three of the four straight lines correspond to the pressure effects of the amorphous phase of PEO,the crystalline phase of PEO,and the new phase of CuBr2.Hence the composition dependence of the corresponding activation volume and cutoff pressure of the three types of conductivity-pressure effects can be calculated.%用混溶蒸发法制备出一系列高聚物P(EO)n-CuBr2(n=4,8,12,16,24)薄膜,并详细测量它们在0.1~350MPa静水压范围内的复阻抗谱、在0.1~2400MPa静水压范围内的交流电导率以及介电常数。结果表明:离子电导率对压力的依赖关系(σ-p曲线)是条折线,可分解为四条直线相迭加。进一步做X射线衍射物相分析,它们分别归于PEO非晶相的压力效应、PEO结晶相的压力效应和析出CuBr2新相的压力效应。由此计算出上述三种不同相所对应的激活体积、截止压力各自随高聚物P(EO)n-CuBr薄膜组分的变化。为减小离子电导率的压力效应提供了物理基础。

  7. Properties of Electroless Ni-Cu-P Plating Coating on Nd-Fe-B Permanent Magnets%烧结Nd-Fe-B永磁体化学镀Ni-Cu-P性能研究

    Institute of Scientific and Technical Information of China (English)

    于升学; 宋伟明; 邵光杰

    2001-01-01

    通过适当的预处理工艺,在烧结Nd-Fe-B永磁体表面直接实现化学镀Ni-Cu-P,不需要预镀处理.用X-射线衍射仪、扫描电镜分析了镀层的结构和表面形貌,测试了镀层的耐蚀性能和结合强度.结果表明,Nd-Fe-B永磁体经化学镀NiCu-P后,可以获得与基体结合良好、孔隙率低、耐蚀性高的镀层.

  8. ADSORPSI ION CU(II MENGGUNAKAN PASIR LAUT TERAKTIVASI H2SO4 DAN TERSALUT Fe2O3

    Directory of Open Access Journals (Sweden)

    DS Pambudi

    2014-11-01

    Full Text Available Pasir laut merupakan bahan alam yang melimpah. Selain digunakan sebagai bahan bangunan, pasir dapat dimanfaatkan sebagai penjerap ion logam berat mengingat 30% lebih dari volumenya adalah pori-pori. Tujuan penelitian adalah untuk mengetahui kapasitas adsorpsi ion logam Cu(II menggunakan pasir laut kontrol, pasir laut teraktivasi H2SO4, pasir laut tersalut Fe2O3, serta pasir laut teraktivasi H2SO4 dan tersalut Fe2O3. Ada dua macam pasir laut yang digunakan, yaitu pasir hitam dan pasir putih. Kajian yang dilakukan meliputi optimasi adsorben pada variasi pH, konsentrasi ion logam, dan waktu kontak. Optimasi pH diperoleh pada pH 7, optimasi konsentasi ion logam diperoleh 250 ppm untuk pasir hitam dan 200 ppm untuk pasir putih, dan optimasi waktu diperoleh 60 menit untuk pasir hitam dan 90 menit untuk pasir putih. Kapasitas adsorpsi pasir laut teraktivasi H2SO4 dan tersalut Fe2O3 dalam menyerap ion logam tembaga sebesar 24,8634 mg/g untuk pasir hitam dan 19,8854 mg/g untuk pasir putih. Sebanyak 6,5 g pasir hitam teraktivasi H2SO4 dan tersalut Fe2O3 digunakan untuk menyerap limbah pada konsentrasi Cu(II sebesar 2960,32 ppm dengan persentase teradsorpsi sebesar 94,70%. Sedangkan pada pasir putih teraktivasi H2SO4 dan tersalut Fe2O3, sebanyak 8 g pasir digunakan untuk menyerap limbah dengan konsentrasi Cu(II sebesar 2984,13 ppm, hasilnya menunjukkan 92,56% ion logam Cu(II teradsorp. Sea sand is abundant natural materials. In addition to be used as a building material, sand can be utilized as heavy metal ion adsorbent, because it has quite a lot of pores, i.e 30% more than its volume. The purpose of this study was to determine the adsorption capacity of Cu(II ions using sea sand alone as control, H2SO4-activated sea sand, Fe2O3-coated sea sand, as well as H2SO4-activated and Fe2O3-coated sea sand. Two kinds of sea sand have been used in the research, i.e the black sand and the white sand. Studies were performed to examine the optimization of the

  9. Mn-Cu-Ce-Fe/REY系列催化剂上NH3选择性催化还原NO性能%Selective catalytic reduction of NO with NH3 over Mn-Cu-Ce-Fe/REY catalysts

    Institute of Scientific and Technical Information of China (English)

    任翠涛; 李滨; 王虹; 李翠清; 丁福臣; 宋永吉

    2012-01-01

    Mn-Cu-Fe-Ce/REY catalysts were designed with orthogonal experimental method and prepared by impregnation method. The catalytic performance of the catalysts for selective reduction of NO with NH3 was evaluated in the presence of S02 and in a fixed bed micro-reactor. The effects of Mn, Cu, Fe and Ce components on the catalytic activity were investigated. The catalysts were characterized by XRD, SEM and H2 -TPR. The results showed that the sequence of the influence of active components on catalyst activity from big to small was as follows; Cu > Fe > Ce > Mn, and the activity of the catalysts was affected by their redox properties.%采用正交实验设计和浸渍法制备Mn-Cu-Fe-Ce/REY催化剂.采用固定床微型反应器评价SO2存在下催化剂在NH3选择性催化还原NO反应中的活性,考察Mn、Cu、Fe和Ce各活性组分对催化剂活性的影响,并采用XRD、H2-TPR和SEM等手段对催化剂进行表征.结果表明,Mn、Cu、Fe和Ce各活性组分对催化剂活性影响顺序为:Cu> Fe> Ce> Mn,催化剂的氧化还原性能影响催化剂活性.

  10. Mössbauer study of Cu0.5Fe0.5Cr2S4

    Science.gov (United States)

    Ok, Hang Nam; Baek, Kyung Seon; Lee, Heung Soo; Kim, Chul Sung

    1990-01-01

    Cu0.5Fe0.05Cr2S4 has been studied by Mössbauer spectroscopy and x-ray diffraction. The crystal structure is found to be a cubic spinel with the lattice parameter a0=9.922 Å. The temperature dependence of both the magnetic hyperfine field and magnetization is explained by the Néel theory of ferrimagnetism using three exchange integrals: JFe-Cr/kB=-13.7 K, JFe-Fe/kB=-8.3 K, and JCr-Cr/kB=8.7 K.

  11. On the Path to Optimizing the Al-Co-Cr-Cu-Fe-Ni-Ti High Entropy Alloy Family for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Anna M. Manzoni

    2016-03-01

    Full Text Available The most commonly investigated high entropy alloy, AlCoCrCuFeNi, has been chosen for optimization of its microstructural and mechanical properties by means of compositional changes and heat treatments. Among the different available optimization paths, the decrease of segregating element Cu, the increase of oxidation protective elements Al and Cr and the approach towards a γ-γ′ microstructure like in Ni-based superalloys have been probed and compared. Microscopical observations have been made for every optimization step. Vickers microhardness measurements and/or tensile/compression test have been carried out when the alloy was appropriate. Five derived alloys AlCoCrFeNi, Al23Co15Cr23Cu8Fe15Ni16, Al8Co17Cr17Cu8Fe17Ni33, Al8Co17Cr14Cu8Fe17Ni34.8Mo0.1Ti1W0.1 and Al10Co25Cr8Fe15Ni36Ti6 (all at.% have been compared to the original AlCoCrCuFeNi and the most promising one has been selected for further investigation.

  12. Reduction of CO2 to low carbon alcohols on CuO FCs/Fe2O3 NTs catalyst with photoelectric dual catalytic interfaces.

    Science.gov (United States)

    Li, Peiqiang; Wang, Huying; Xu, Jinfeng; Jing, Hua; Zhang, Jun; Han, Haixiang; Lu, Fusui

    2013-12-01

    In this paper, the CuO FCs/Fe2O3 NTs catalyst was obtained after Fe2O3 nanotubes (Fe2O3 NTs) were decorated with CuO flower clusters (CuO FCs) by the pulse electrochemical deposition method. The in situ vertically aligned Fe2O3 NTs were prepared on the ferrous substrate by a potentiostatic anodization method. The SEM result showed the volcano-like Fe2O3 NTs were arranged in order and the CuO FCs constituted of flaky CuO distributed on the Fe2O3 NTs surface uniformly. After CuO FCs were loaded on Fe2O3 NTs, the absorption of visible light was enhanced noticeably, and its band gap narrowed to 1.78 eV from 2.03 eV. The conduction band and valence band locating at -0.73 eV and 1.05 eV, respectively were further obtained. In the PEC reduction of CO2 process, methanol and ethanol were two major products identified by chromatography. Their contents reached 1.00 mmol L(-1) cm(-2) and 107.38 μmol L(-1) cm(-2) after 6 h, respectively. This high-efficiency catalyst with photoelectric dual catalytic interfaces has a great guidance and reference significance for CO2 reduction to liquid carbon fuels.

  13. On the electronic structure and thermoelectric properties of BiTeBr and BiTeI single crystals and of BiTeI with the addition of BiI{sub 3} and CuI

    Energy Technology Data Exchange (ETDEWEB)

    Kulbachinskii, Vladimir A., E-mail: kulb@mig.phys.msu.ru [Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Kytin, Vladimir G.; Kudryashov, Alexey A. [Faculty of Physics, Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Kuznetsov, Alexei N.; Shevelkov, Andrei V. [Chemistry Department, Lomonosov Moscow State University, Moscow 119991 (Russian Federation)

    2012-09-15

    The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin-orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. The optimized crystal structures show a tendency for the Bi-X (X=Br, I) bond elongation compared to the Bi-Te one. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering model. Because of larger thermopower BiTeBr exhibits a twice higher thermoelectric figure-of-merit near room temperature, ZT=0.17, compared to BiTeI. The addition of 1 mass% of BiI{sub 3} or CuI to BiTeI decreases the mobility of electrons by two orders of magnitude, leading to significantly lower electrical conductivity, but at the same time effectively reduces the thermal conductivity. The prospects of further enhancing the thermoelectric efficiency are briefly discussed. - Graphical abstract: View of the crystal structure of BiTeBr is shown in the figure The optimized crystal structures show a tendency for the Bi-X (X=Br, I) bond elongation compared to the Bi-Te one. The electronic structures were calculated for BiTeBr and BiTeI using the density-functional theory approach and accounting for the strong spin-orbital interaction. Qualitatively, the band structures for two compounds are similar, showing strong mixing of the p states of all elements in vicinity of the Fermi level, with the band gaps of 0.595 and 0.478 eV for BiTeBr and BiTeI, respectively. Both compounds are intrinsic n-type semiconductors but display a metallic-like conductivity coupled to rather large thermopower, which is rationalized within the frames of the acoustic phonons scattering model. The

  14. Atomic scale study of CU clustering and pseudo-homogeneous Fe–Si nanocrystallization in soft magnetic FeSiNbB(CU) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pradeep, K.G. [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf (Germany); Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen (Germany); Herzer, G. [Vacuumschmelze GmbH & Co. KG, Grüner Weg 37, 63450 Hanau (Germany); Raabe, D. [Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf (Germany)

    2015-12-15

    A local electrode atom probe has been employed to trace the onset of Cu clustering followed by their coarsening and subsequent growth upon rapid (10 s) annealing of an amorphous Fe{sub 73.5}Si{sub 15.5}Cu{sub 1}Nb{sub 3}B{sub 7} alloy. It has been found that the clustering of Cu atoms introduces heterogeneities in the amorphous matrix, leading to the formation of Fe rich regions which crystallizes pseudo-homogeneously into Fe–Si nanocrystals upon annealing. In this paper, we present the data treatment method that allows for the visualization of these different phases and to understand their morphology while still quantifying them in terms of their size, number density and volume fraction. The crystallite size of Fe–Si nanocrystals as estimated from the atom probe data are found to be in good agreement with other complementary techniques like XRD and TEM, emphasizing the importance of this approach towards accurate structural analysis. In addition, a composition driven data segmentation approach has been attempted to determine and distinguish nanocrystalline regions from the remaining amorphous matrix. Such an analysis introduces the possibility of retrieving crystallographic information from extremely fine (2–4 nm sized) nanocrystalline regions of very low volume fraction (< 5 Vol%) thereby providing crucial in-sights into the chemical heterogeneity induced crystallization process of amorphous materials.

  15. Effect of the partial oxygen pressure on Cu-NiFe2O4 cermet phase%氧分压对Cu-NiFe2O4金属陶瓷相成份的影响

    Institute of Scientific and Technical Information of China (English)

    张明霞

    2009-01-01

    用高温固相法合成的NiFe2O4陶瓷粉末,选取Cu为金属陶瓷的金属相成分,研究了氧分压对Cu-NiFe2O4金属陶瓷的相成份的影响,结果表明:当烧结温度为1150℃,氧分压大于2.23Pa时,Cu被大量氧化;氧分压小于4.2×10-3Pa时,Cu和离解的Ni反应生产Cu3.8Ni合金,试样的导电性或抗氧化性都会降低,1150℃下烧结制备Cu-NiFe2O4金属陶瓷的最佳氧分压是( 0.3-42.0)×10-2Pa.

  16. Crystalline structure, magnetic and magnetoelastic properties of Nd6Fe13-xCoxCu intermetallic compounds

    Directory of Open Access Journals (Sweden)

    P Iranmanesh

    2011-03-01

    Full Text Available Influence of the partial substitution of Co for Fe on the structural, magnetic and magnetoelastic properties of Nd6Fe13Cu compounds are investigated. Analysis of X-ray diffraction patterns indicates that the multi-phase sample is formed for all samples. Upon Co substitution, the second phase Nd2Fe17, Nd2Fe17-yCoy with 0 < y < 1 and Nd2Fe17-zCoz with 1 < z < 2 is formed in the samples with x = 0, 1, 2, respectively so that the lattice parameters are decreased and the Curie temperature is increased. Due to the ferromagnetic phase Nd2Fe17-yCoy in sample with x = 1, the change of the anisotropy and increase of exchange effects are observed. The effects of long-range magnetic ordering processes on Néel temperature clearly appear in the temperature dependence of the spontaneous magnetostriction. Longitudinal (λl and transverse (λt magnetostrictions are measured to study the magnetoelastic behaviour of these compounds using a strain gauge method. In the low field region, magnetostrictive strains are small and then increase with increasing fields. Strong pining center of Nd atoms that creates large magnetocrystalline anisotropy prevents easy movement of domain walls. In the sample with x = 0, the magnetostriction contribution from the rare earth sublattice (Nd dominates at low temperature and the Fe sublattice contribution becomes increasingly important as temperature rises.

  17. Phase transition from fcc to bcc structure of the Cu-clusters during nanocrystallization of Fe85.2Si1B9P4Cu0.8 soft magnetic alloy

    OpenAIRE

    Masahiko Nishijima; Makoto Matsuura; Kana Takenaka; Akira Takeuchi; Hironori Ofuchi; Akihiro Makino

    2014-01-01

    A role of Cu on the nanocrystallization of an Fe85.2Si1B9P4Cu0.8 alloy was investigated by X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM). The Cu K-edge XAFS results show that local structure around Cu is disordered for the as-quenched sample whereas it changes to fcc-like structure at 613 K. The fcc Cu-clusters are, however, thermodynamically unstable and begin to transform into bcc structure at 638 K. An explicit bcc structure is observed for the sample an...

  18. Crystal structure, thermal studies, Hirshfeld surface analysis, vibrational and DFT investigation of organic-inorganic hybrid compound [C9H6NOBr2]2CuBr4·2H2O

    Science.gov (United States)

    Mesbeh, Radhia; Hamdi, Besma; Zouari, Ridha

    2016-12-01

    Single crystals of a hybrid organic/inorganic material with the formula [C9H6NOBr2]2CuBr4·2H2O were studied by X-ray diffraction. The compound crystallizes in the monoclinic system, space group C2/c with the following unit cell parameters: a = 7.8201 (12) Ǻ, b = 18.203 (3) Ǻ, c = 19.486 (3) Ǻ, β = 98.330 (5)°, Z = 4, V = 2744.6 (7) Ǻ3. Crystal structure was solved with a final R = 5.66% for 3483 independent reflections. The atomic arrangement shows an alternation of organic and inorganic layers. Between layers, the cohesion is performed via Osbnd H⋯Br, Csbnd H⋯Br, Nsbnd H⋯Br, Nsbnd H⋯O and Osbnd H⋯O hydrogen bending. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements have been carried out on [C9H6NOBr2]2CuBr4·2H2O crystal in the temperature range between 50 and 500 °C. The assignment of the observed bands in the solid state FTIR and Raman spectra of the compound was assisted by the theoretically predicted frequencies and compared with data previously reported for similar compounds. The theoretical geometrical parameters in the ground state have been investigated by density functional theory (DFT) with the B3LYP/LanL2DZ level of theory. The optical properties were investigated by optical absorption and show two bands at 279, 300 nm. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface.

  19. Enhancing magnetic properties of anisotropic NdDyFeCoNbCuB powder by applying magnetic field at high temperature during hydrogen desorption

    Institute of Scientific and Technical Information of China (English)

    LUO Jianjun; P.De Rango; D.Fruchart; MEI Jinna; HU Rui; LI Jinshan; ZHOU Lian

    2010-01-01

    Anisotropic powder was prepared with precursor (NdDy)-(FeCoNbCu)-B sintered magnets by hydrogen decrepitation,desorption,and subsequent annealing treatment.The hydrogen desorption was performed in magnetic fields of 0,1,3,and 5 T.The orientation of tetragonal phase grains of the powder was evaluated from the hysteresis loops measured by extraction magnetometer.Residual hydrogen content of the powder was evaluated by thermal-magnetic analysis.The powder with Hcj,Br,and (BH)max of 1138 kA.m-1,1.029 T,and 172.5 kJ.m-3,respectively,was achieved under the condition of the magnetic field of 3 T.Magnetic properties of the powder,especially,the remanence of the powder,are enhanced upon magnetic fields,which is due to better orientation of powder particles and less residual hydrogen in the powder resulted from the magnetic field during the hydrogen desorption process.

  20. Production of sulfate radical from peroxymonosulfate induced by a magnetically separable CuFe2O4 spinel in water: Efficiency, stability, and mechanism

    KAUST Repository

    Zhang, Tao

    2013-03-19

    A simple, nonhazardous, efficient and low energy-consuming process is desirable to generate powerful radicals from peroxymonosulfate (PMS) for recalcitrant pollutant removal. In this work, the production of radical species from PMS induced by a magnetic CuFe2O4 spinel was studied. Iopromide, a recalcitrant model pollutant, was used to investigate the efficiency of this process. CuFe2O4 showed higher activity and 30 times lower Cu2+ leaching (1.5 μg L-1 per 100 mg L-1) than a well-crystallized CuO at the same dosage. CuFe 2O4 maintained its activity and crystallinity during repeated batch experiments. In comparison, the activity of CuO declined significantly, which was ascribed to the deterioration in its degree of crystallinity. The efficiency of the PMS/CuFe2O4 was highest at neutral pH and decreased at acidic and alkaline pHs. Sulfate radical was the primary radical species responsible for the iopromide degradation. On the basis of the stoichiometry of oxalate degradation in the PMS/CuFe 2O4, the radical production yield from PMS was determined to be near 1 mol/mol. The PMS decomposition involved an inner-sphere complexation with the oxide\\'s surface Cu(II) sites. In situ characterization of the oxide surface with ATR-FTIR and Raman during the PMS decomposition suggested that surface Cu(II)-Cu(III)-Cu(II) redox cycle was responsible for the efficient sulfate radical generation from PMS. © 2013 American Chemical Society.

  1. Visible light photo-degradation of methylene blue over Fe or Cu promoted ZnO nanoparticles.

    Science.gov (United States)

    Mardani, Hamid Reza; Forouzani, Mehdi; Ziari, Mitra; Biparva, Pourya

    2015-04-15

    CuxZn(1-x)O, FexZn(1-x)O (x=0.01) and ZnO nanoparticles were and were characterized by X-ray diffraction, ultraviolet and visible spectroscopy, FTIR spectroscopy and SEM. The photodegradation of an aqueous solution of methylene blue (as an organic pollutant) by nanoparticles with H2O2 (30%) under visible light and the progress of the reaction were monitored by UV-Vis spectroscopy absorption. The photocatalytic oxidation efficiency of all nanoparticles was 100% at the appropriate time. The degradation time was 90 min for FeZnO, 120 min for CuZnO and 210 min for ZnO. This indicates that the photocatalytic activity of the doped nanoparticles was better than that of ZnO alone. ZnO doped with a small amount of Fe or Cu decreased the size of the nanoparticles and the band gap and increased photocatalytic efficiency.

  2. Role of Disclinations and Nanocrystalline State in the Formation of Quasicrystalline Phases on Mechanical Alloying of Cu-Fe Powders

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of quasicrystalline phases were monitored using X-ray diffraction. Diffusion of Fe into the Cu matrix is proposed as the cause which triggers the instability of crystalline phases and leads to the formation of quasicrystalline phases after 10 h of milling. Milling for 100 h resulted in two different quasicrystalline phases with different lattice constants. Role of the nanocrystalline microstructure as an important criterion for the destabilisation of crystalline phases is explained. It is suggested that the formation of nanocrystalline microstructure and their subsequent transformation into quasicrystalline phases may be associated with a continuous increase in the disclination content of the system, which had formed as a result of continued milling and mechanical deformation.

  3. Separation in liquid and the formation of supersaturated solid solutions in Fe-Cu alloys upon rapid laser melting

    Science.gov (United States)

    Kharanzhevskiy, E. V.

    2016-09-01

    The structure of compacted specimens produced using the rapid laser melting of ultradispersed Fe-50 wt % Cu powders has been studied. The original powder was produced via the mechanical milling of iron and copper powders in a planetary-type ball mill. It has been found that the structure of the compacted specimens produced using rapid laser melting exhibits signs of the initial stages of separation in supercooled liquid. It has been shown using X-ray diffraction analysis as well as scanning and transmission electron microscopy that the final structure contains a supersaturated (Fe; Cu) solid solution formed from the high-speed movement of the solidification front and the nonequilibrium capture of copper by the moving front.

  4. Creating textured substrate tapes of Cu-Fe alloys for second-generation high-temperature superconductors

    Science.gov (United States)

    Khlebnikova, Yu. V.; Gervas'eva, I. V.; Suaridze, T. R.; Rodionov, D. P.; Egorova, L. Yu.

    2014-10-01

    It is established that Cu-1.6 at % Fe alloy tapes obtained through cold rolling to 98.9% followed by recrystallization annealing possess a sharp cube texture, which opens prospects of using thin tapes of this alloy as substrates for second-generation high-temperature superconductors. The optimum regime of annealing is determined that allows an alloy with sharp biaxial texture containing more than 97% cubic grains to be obtained. The yield stress of a 90-μm-thick Cu-1.6 at % Fe alloy tape upon recrystallization annealing at 800°C for 1 h amounts to 78 MPa, which is about three times higher than the value for a pure copper tape with sharp cube texture.

  5. Mechanisms for the Movement of Fe,Mn,Cu and Zn to Plant Roots in Loessal Soil and Lou Soil

    Institute of Scientific and Technical Information of China (English)

    XUMINGGANG; ZHANGYIPING; 等

    1996-01-01

    The pot experiments were conducted in the artificial climate laboratories to determine the relative importance of mass flow and diffusion in supplying ,Fe,Mn,Cu,and Zn to wheat,soybean and maize plants growing in loessal soil and lou soil.It was found that the calculated relative contribution of mass flow of iron,manganese,copper and zinc to plant uptake varied from 5% to more than 100%,depending on the crop species and soil types as well as plant growth stage,soil moisture,atmosphere humidity,etc.The results also showed that the major transportation mechanisms of these micronutrients in soil-root system varied with the crop and its growth,climate and soil,singnificantly,In general,mass flow was more important for Cu and Zn and diffusion was more significant for Fe and Mn at the seedling stage.

  6. Effect of crystallisation on the magnetic properties of FeCuNbBSi amorphous thin films produced by sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Celegato, Federica; Coisson, Marco; Tiberto, Paola; Vinai, Franco [INRIM, Electromagnetism Division, Torino (Italy); Baricco, Marcello [Dipartimento di Chimica IFM and NIS, Universita di Torino (Italy)

    2011-11-15

    Soft magnetic thin films of FeCuNbSiB alloy having different thickness were deposited on a Si{sub 3}N{sub 4} substrate by rf sputtering. The target was made of amorphous ribbons having nominal composition Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9}. The amorphicity of as-deposited films has been checked by X-ray diffraction technique. Selected samples have been submitted to controlled annealing to induce the amorphous-to-crystalline transformation. The influence of thermal treatments on the hysteresis properties has been studied as a function of thickness and microstructure on as prepared and annealed samples. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Effect of Cu on the evolution of precipitation in an Fe-Cr-Ni-Al-Ti maraging steel

    Energy Technology Data Exchange (ETDEWEB)

    Schnitzer, Ronald, E-mail: ronald.schnitzer@unileoben.ac.at [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Schober, Michael [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria); Zinner, Silvia [Boehler Edelstahl GmbH and Co KG, Mariazeller Strasse 25, A-8605 Kapfenberg (Austria); Leitner, Harald [Christian Doppler Laboratory for Early Stages of Precipitation, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)] [Department of Physical Metallurgy and Materials Testing, University of Leoben, Franz-Josef-Strasse 18, A-8700 Leoben (Austria)

    2010-06-15

    The evolution of precipitates in an Fe-Cr-Ni-Al-Ti stainless maraging steel alloyed with Cu was investigated during aging at 525 deg. C. Atom probe tomography was used to reveal the development of precipitates and to determine their chemical composition. Two types of precipitates were observed to form during the aging process. Based on their chemical composition these are assumed to be NiAl B2 and Ni{sub 3}(Ti,Al) ({eta}-phase). The two phases of precipitates were found to develop independently of each other and the addition of Cu was found to accelerate precipitation. However, the effect of Cu on the nucleation of these phases is different: on the one hand, in the case of NiAl, Cu is incorporated and thus reduces the activation energy by reducing the lattice misfit; on the other hand, Cu acts as a nucleation site for the precipitation of Ni{sub 3}(Ti,Al) by forming independent Cu clusters.

  8. Self-lubricating tribological characterization of lead free Fe-Cu based plain bearing material

    Directory of Open Access Journals (Sweden)

    Shuhaib Mushtaq

    2017-03-01

    Full Text Available The negative impact of lead on environment and thereby its reciprocity on the health of mankind, there is a growing emphasis on resisting the usage of lead in bearings. Owing to this, new bearing materials that provide comparable tribological performance to that of lead containing alloys are being developed. In this study, lead free Fe-Cu based powders with addition of elements such as tin, molybdenum disulfide and Nano boron nitride (BN have been developed by powder metallurgy (PM technique in order to improve the tribological and mechanical properties. The powder mixtures were compressed at a pressure of 500 MPa, and then sintered in dry hydrogen atmosphere at 9000C for 50 minutes. The mechanical and tribological properties obtained due to addition of the said elements is presented in this study. The tribological behavior of the selected alloys is analyzed by reciprocating-sliding tests under dry conditions. The morphology of wear scars and the microstructure of the wear surfaces were investigated. The material with 2.5 wt.% of Sn exhibited the highest value of hardness, the material with 7.5 wt.% of Nano BN comparably shows the low coefficient of friction and wear rate as compared with 5 wt.% of Nano BN.

  9. The Use of Al, Cu, and Fe in an Integrated Electrocoagulation-Ozonation Process

    Directory of Open Access Journals (Sweden)

    Carlos E. Barrera Díaz

    2015-01-01

    Full Text Available This study presents the effect of supplying electrochemically generated metallic ions (Al, Cu, and Fe during an ozonation process for treating industrial wastewater. The pollutant removal efficiencies of the electrocoagulation (EC, ozonation, and coupled EC-ozonation processes were examined by the decrease in chemical oxygen demand (COD as a function of treatment time. The EC was performed in a raw industrial wastewater, which has contributions from 39 chemical, 34 metal finishing, 22 textile, 11 leather, and 5 automotive plants, at pH (7.3 using a current density of 150 A/m2 for 60 min, giving a 45% reduction in COD. The ozonation process was more effective with the same wastewater, reducing the COD by 52% after 60 min of treatment. Combining the EC and ozonation methods resulted in a synergistic process that improves the reduction of COD in a shorter time. In just 12 min the integrated process reduced the COD by 88%. Thus, the combination of EC and ozonation processes improves noticeably the wastewater quality, decreasing the treatment time and also reducing the sludge production.

  10. Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling

    Energy Technology Data Exchange (ETDEWEB)

    Aravinthan, D.; Daniel, M. [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli - 620 024 (India); Sabareesan, P. [Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur - 613 401 (India)

    2015-07-15

    The impact of orange peel coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the switching dynamics of magnetization of the free layer governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The value of the critical current required to initiate the magnetization switching is calculated analytically by solving the LLGS equation and verified the same through numerical analysis. Results of numerical simulation of the LLGS equation using Runge-Kutta fourth order procedure shows that the presence of orange peel coupling between the spacer and the ferromagnetic layers reduces the switching time of the nanopillar device from 67 ps to 48 ps for an applied current density of 4 × 10{sup 12}Am{sup −2}. Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 10{sup 12}Am{sup −2} to 1.39 × 10{sup 12}Am{sup −2}.

  11. Current induced magnetization switching in Co/Cu/Ni-Fe nanopillar with orange peel coupling

    Directory of Open Access Journals (Sweden)

    D. Aravinthan

    2015-07-01

    Full Text Available The impact of orange peel coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the switching dynamics of magnetization of the free layer governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS equation. The value of the critical current required to initiate the magnetization switching is calculated analytically by solving the LLGS equation and verified the same through numerical analysis. Results of numerical simulation of the LLGS equation using Runge-Kutta fourth order procedure shows that the presence of orange peel coupling between the spacer and the ferromagnetic layers reduces the switching time of the nanopillar device from 67 ps to 48 ps for an applied current density of 4 × 1012Am−2. Also, the presence of orange peel coupling reduces the critical current required to initiate switching, and in this case, from 1.65 × 1012Am−2 to 1.39 × 1012Am−2.

  12. Lifting of the Au(100) surface reconstruction by Pt, Cr, Fe, and Cu adsorption

    Science.gov (United States)

    Tempas, Christopher D.; Skomski, Daniel; Tait, Steven L.

    2016-12-01

    The adsorption and growth of metals on the surfaces of other metals is an important topic for studies of heterogeneous catalysis and bimetallic nanoparticles. The surface structure of these systems impacts nanoparticle growth, catalytic activity, and reaction selectivity. In these experiments, platinum, chromium, iron, or copper were vapor deposited on the reconstructed Au(100) surface. The initial growth of each metal was studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). Each of the four metals forms anisotropic rectangular islands oriented in the direction of the gold reconstruction rows. The gradual lifting of the surface reconstruction by increased metal coverage is observed, and the reconstruction is fully lifted after 0.5 ML of Pt, Cr, or Fe, or by 3.3 ML of Cu. After the reconstruction is lifted, the island shape changes from rectangular to square, illustrating the effect of surface structure on growth. Second layer islands begin to form before the completion of the first full layer.

  13. Strong and Stable Nanocomposites Prepared by High-Pressure Torsion of Cu-Coated Fe Powders

    Directory of Open Access Journals (Sweden)

    Timo Müller

    2016-09-01

    Full Text Available Segregation and chemical inhomogeneity are well-known problems in powder metallurgy and are also an issue for new applications of powder mixtures, for example as starting materials for severe plastic deformation. In this study, Cu-coated Fe powder was prepared via immersion deposition, inductively hot-pressed and subsequently deformed using high-pressure torsion. The homogeneity of the pressed material was found to be much better than that of powder mixtures that were prepared for comparison. During severe plastic deformation, higher hardness was observed for the coated powder as compared to powder mixtures even after low strains. In the saturation state, the coated powder was found to result in a hardness of about 600 HV, which is significantly harder than for the powder mixtures. This is attributed to the greater amount of impurities introduced by the coating process. It is shown that coated powders are promising starting materials for severe plastic deformation in order to reduce the amount of strain necessary to reach the saturation state and to obtain high strength and more homogeneous mechanical alloying.

  14. Photoluminescence and semiconducting behavior of Fe, Co, Ni and Cu implanted in heavy metal oxide glasses

    Directory of Open Access Journals (Sweden)

    Mohamed A. Marzouk

    2016-07-01

    Full Text Available Transition metal ions (0.5 wt% of Fe2O3, CoO, NiO or CuO doped heavy metal oxide glasses having chemical composition of 60PbO·20Bi2O3·20 MxOy mol% (where MxOy = B2O3 or SiO2 or P2O5 were prepared by conventional melt annealing method. Combined optical and photoluminescence properties have been measured and employed to evaluate the prepared glassy samples. From the absorption edge data, the values of the optical band gap Eopt, Urbach energy (ΔE and refractive index were calculated to estimate semiconducting behavior. Photoluminescence and values of the optical energy gap were found to be dependent on the glass composition. The variations of the photoluminescence intensity, values of optical band gap, Urbach energy and refractive index gave an indication to use the prepared glasses for design of novel functional optical materials with higher optical performance.

  15. Ultrafast demagnetization of FePt:Cu thin films and the role of magnetic heat capacity

    Science.gov (United States)

    Kimling, Johannes; Kimling, Judith; Wilson, R. B.; Hebler, Birgit; Albrecht, Manfred; Cahill, David G.

    2014-12-01

    The phenomenon of different time scales of ultrafast demagnetization has attracted much attention. This so-called diversity of ultrafast demagnetization has been explained by the microscopic three temperature model (M3TM) and by the Landau-Lifshitz-Bloch model (LLBM). Here, we revisit the basic three temperature model (3TM) and provide a general criterion for explaining the different time scales observed. We focus on the role of magnetic heat capacity, which we find mainly determines the slowing down of the demagnetization time with increasing ambient temperature and laser fluence. In this context, we clarify the role of magnetic heat capacity in the M3TM and compare the 3TM with the LLBM. To illustrate the role of magnetic heat capacity, we present a simulation of ultrafast demagnetization of Ni. Furthermore, we present time-resolved magneto-optic Kerr effect measurements of ultrafast demagnetization and specific heat of Fe46Cu6Pt48 from 300 K to close to its Curie temperature. While most of the prior experimental research used high-fluence laser pulses causing sizable temperature excursions of the sample, our experiments involve small temperature excursions, which are crucial for studying the role of magnetic heat capacity in ultrafast demagnetization. Our experimental results corroborate that the slowing down of ultrafast demagnetization is dominated by the increase of the magnetic heat capacity near the Curie temperature.

  16. Highly Efficient Synthesis of Clean Biofuels from Biomass Using FeCuZnAIK Catalyst

    Institute of Scientific and Technical Information of China (English)

    Song-bai Qiu; Yong Xu; Tong-qi Ye; Fei-yan Gong; Zhi Yang; Mitsuo Yamamoto; Yong Liu; Quan-xin Li

    2011-01-01

    Highly efficient synthesis of clean biofuels using the bio-syngas obtained from biomass gasification was performed over Fe1.5Cu1Zn1Al1K0.117 catalyst.The maximum biofuel yield from the bio-syngas reaches about 1.59 kg biofuels/(kgcatal·h) with a contribution of 0.57 kg alcohols/(kgcatal·h) and 1.02 kg liquid hydrocarbons/(kgcatal·h).The alcohol products in the resulting biofuels were dominated by the C2+ alcohols (mainly C2-C6 alcohols) with a content of 73.55%-89.98%.The selectivity of the liquid hydrocarbons (C5+) in the hydrocarbon products ranges from 60.37% to 70.94%.The synthesis biofuels also possess a higher heat value of 40.53-41.49 MJ/kg.The effects of the synthesis conditions,including temperature,pressure,and gas hourly space velocity,on the biofuel synthesis were investigated in detail.The catalyst features were characterized by inductively coupled plasma and atomic emission spectroscopy,X-ray diffraction,temperature programmed reduction,and the N2 adsorption-desorption isotherms measurements.The present biofuel synthesis with a higher biofuel yield and a higher selectivity of liquid hydrocarbons and C2+ alcohols may be a potentially useful route to produce clean biofuels and chemicals from biomass.

  17. Magnetic ageing study of high and medium permeability nanocrystalline FeSiCuNbB alloys

    Science.gov (United States)

    Lekdim, Atef; Morel, Laurent; Raulet, Marie-Ange

    2017-04-01

    increasing the energy efficiency is one of the most important issues in modern power electronic systems. In aircraft applications, the energy efficiency must be associated with a maximum reduction of mass and volume, so a high components compactness. A consequence from this compactness is the increase of operating temperature. Thus, the magnetic materials used in these applications, have to work at high temperature. It raises the question of the thermal ageing problem. The reliability of these components operating at this condition becomes a real problem which deserves serious interest. Our work takes part in this context by studying the magnetic material thermal ageing. The nanocrystalline materials are getting more and more used in power electronic applications. Main advantages of nanocrystalline materials compared to ferrite are: high saturation flux density of almost 1.25 T and low dynamic losses for low and medium frequencies. The nanocrystalline Fe73.5Cu1Nb3Si15.5B7 alloys have been chosen in our aging study. This study is based on monitoring the magnetic characteristics for several continuous thermal ageing (100, 150, 200 and 240 °C). An important experimental work of magnetic characterization is being done following a specific monitoring protocol. Elsewhere, X-Ray Diffraction and magnetostriction measurements were carried out to support the study of the anisotropy energies evolution with ageing. This latter is discussed in this paper to explain and give hypothesis about the ageing phenomena.

  18. Effect of Nb and Cu on the crystallization behavior of under-stoichiometric Nd-Fe-B alloys

    Science.gov (United States)

    Salazar, D.; Martín-Cid, A.; Madugundo, R.; Garitaonandia, J. S.; Barandiaran, J. M.; Hadjipanayis, G. C.

    2017-01-01

    In this work, we present a complete study of the influence of Nb and Cu addition on the crystallization behavior of Nd-lean Nd-Fe-B melt-spun alloys. Alloys with compositions Nd10-x-y Fe84B6Nb x Cu y (x  =  1, y  =  0 and x  =  0.5, y  =  0.5) were melt-spun at different wheel speeds (15-40 m s-1) to obtain samples in amorphous, highly disordered and nanocrystalline structures. The crystallization process, induced by different heat treatments, was studied by means of differential thermal analysis and x-ray powder thermodiffraction. Magnetic properties of as-made and heat-treated ribbons were measured by magnetometry. The as-made amorphous samples showed a crystallization to the 2:14:1 hard magnetic phase at T 1 ~ 350 °C. Doping with Nb results in an increase of T 1, and addition of Cu lowers T 1. This behavior is explained in terms of an inhibition of grain growth by Nb and a nucleation enhancement by Cu additions. During the crystallization process, a secondary phase (identified as a bcc-Fe-rich phase) is formed. The amount of such a phase increases with the annealing temperature. Coercivity increases upon annealing reaching maxima at 700-750 °C. This can be explained in terms of competition between the two phases formed: the 2:14:1 hard phase and the soft bcc-Fe-rich phase. The highest coercivity of the Nd-lean samples is observed when the microstructure is appropriate and both phases are exchange-coupled.

  19. Structure and properties of cast and splat-quenched high-entropy Al-Cu-Fe-Ni-Si alloys

    Science.gov (United States)

    Bashev, V. F.; Kushnerov, O. I.

    2017-01-01

    The effect of the composition and cooling rate of the melt on the microhardness, phase composition, and fine-structure parameters of as-cast and splat-quenched (SQ) high-entropy (HE) Al-Cu-Fe-Ni-Si alloys was studied. The quenching was performed by conventional splat-cooling technique. The cooling rate was estimated to be 106 K/s. Components of the studied HE alloys were selected taking into account both criteria for designing and estimating their phase composition, which are available in the literature and based on the calculations of the entropy and enthalpy of mixing, and the difference between atomic radii of components as well. According to X-ray diffraction data, the majority of studied Al-Cu-Fe-Ni-Si compositions are two-phase HE alloys, the structure of which consists of disordered solid solutions with bcc and fcc structures. At the same time, the Al0.5CuFeNi alloy is single-phase in terms of X-ray diffraction and has an fcc structure. The studied alloys in the as-cast state have a dendritic structure, whereas, after splat quenching, the uniform small-grained structure is formed. It was found that, as the volume fraction of bcc solid solution in the studied HE alloys increases, the microhardness increases; the as-cast HE Al-Cu-Fe-Ni-Si alloys are characterized by higher microhardness compared to that of splat-quenched alloys. This is likely due to the more equilibrium multiphase state of as-cast alloys.

  20. Effect of annealing treatments on the microwave electromagnetic properties of amorphous FeCuNbSiB microwires

    Institute of Scientific and Technical Information of China (English)

    Liang Di-Fei; Han Man-Gui; Yan Bo; Deng Long-Jiang

    2007-01-01

    The amorphous FeCuNbSiB microwires are fabricated by using the melt extraction method and annealed separately at temperatures T = 573, 673, 723 and 773 K for 1 h. The effect of annealing treatment on the microwave electromagnetic properties of FeCuNbSiB wires/wax composites has been investigated for the first time. It is found that in a frequency range of 0.5-4.0 GHz, the complex permittivity, permeability, magnetic and electric loss tangents of FeCuNbSiB wires/wax composites are strongly dependent on the annealing temperature and frequency. For T = 573,723 and 773K, two resonance peaks are found at frequency f = 1.2 and 3.3GHz. However, for T = 673K, only one resonance peak occurs at f = 3.3 GHz. The resonance peak at f = 1.2 GHz is believed to be due to the stress-induced anisotropy, while the resonance peak at f = 3.3 GHz is attributed to the random anisotropy.

  1. Application of Fe-Cu binary oxide nanoparticles for the removal of hexavalent chromium from aqueous solution.

    Science.gov (United States)

    Khan, Saif Ullah; Zaidi, Rumman; Hassan, Saeikh Z; Farooqi, I H; Azam, Ameer

    2016-01-01

    The adsorption process has been used as an effective technique for the removal of metal ions from aqueous solutions. Groundwater remediation by nanoparticles has received interest in recent years. In the present study, a binary metal oxide of Fe-Cu was prepared and used for the removal of hexavalent chromium from aqueous solution. Batch experiments were performed to investigate the effects of initial Cr (VI) concentration, dose of adsorbent, and pH of solution on the removal efficiency of Cr (VI). The prepared nanostructured Fe-Cu binary oxides were able to reduce the concentration of Cr (VI) in aqueous solution. Binary metal oxides nanoparticle exhibited an outstanding ability to remove Cr (VI) due to high surface area, low particle size, and high inherent activity. The percentage removal efficiency of Cr (VI) increased with nanoparticles doses (0.1 g L(-1)-2.5 g L(-1)), whereas it decreased with initial Cr (VI) concentration (1 mg L(-1)-25 mg L(-1)) and with pH (3-9). The Freundlich model was found to be the better fit for adsorption isotherm. The prepared nanomaterial was characterized using powder X-ray diffraction, scanning electron microscopy (SEM), and ultraviolet (UV)-visible spectroscopy. It showed that the Fe-Cu binary oxides were formed in single phase. SEM micrograph showed aggregates with many nano-sized particles. UV-visible spectroscopy showed quantum confinement effect.

  2. Functionalized graphene oxide quantum dot-PVA hydrogel: a colorimetric sensor for Fe2+, Co2+ and Cu2+ ions

    Science.gov (United States)

    Baruah, Upama; Chowdhury, Devasish

    2016-04-01

    Functionalized graphene oxide quantum dots (GOQDs)-poly(vinyl alcohol) (PVA) hybrid hydrogels were prepared using a simple, facile and cost-effective strategy. GOQDs bearing different surface functional groups were introduced as the cross-linking agent into the PVA matrix thereby resulting in gelation. The four different types of hybrid hydrogels were prepared using graphene oxide, reduced graphene oxide, ester functionalized graphene oxide and amine functionalized GOQDs as cross-linking agents. It was observed that the hybrid hydrogel prepared with amine functionalized GOQDs was the most stable. The potential applicability of using this solid sensing platform has been subsequently explored in an easy, simple, effective and sensitive method for optical detection of M2+ (Fe2+, Co2+ and Cu2+) in aqueous media involving colorimetric detection. Amine functionalized GOQDs-PVA hybrid hydrogel when put into the corresponding solution of Fe2+, Co2+ and Cu2+ renders brown, orange and blue coloration respectively of the solution detecting the presence of Fe2+, Co2+ and Cu2+ ions in the solution. The minimum detection limit observed was 1 × 10-7 M using UV-visible spectroscopy. Further, the applicability of the sensing material was also tested for a mixture of co-existing ions in solution to demonstrate the practical applicability of the system. Insight into the probable mechanistic pathway involved in the detection process is also being discussed.

  3. Intrinsic Kinetics of Dimethyl Ether Synthesis from Plasma Activation of CO2 Hydrogenation over Cu-Fe-Ce/HZSM-5.

    Science.gov (United States)

    Su, Tongming; Zhou, Xinhui; Qin, Zuzeng; Ji, Hongbing

    2017-02-02

    CO2 is activated in a plasma reactor followed by hydrogenation over a Cu-Fe-Ce/HZSM-5 catalyst, and the intrinsic kinetics of the plasma catalytic process are studied. Compared with CO2 hydrogenation using Cu-Fe-Ce/HZSM-5 alone, the CO2 conversion and the dimethyl ether selectivity for the plasma catalytic process are increased by 16.3 %, and 10.1 %, respectively, indicating that the CO2 was activated by the plasma to promote hydrogenation. A study of the intrinsic kinetics shows that the activation energies of methanol formation, the reverse water-gas shift reaction, and methanol dehydration to dimethyl ether are 149.34, 75.47, and 73.18 kJ mol(-1) , respectively, which are lower than if Cu-Fe-Ce/HZSM-5 is used without plasma, indicating that the activation of CO2 in the plasma reduces the activation energy of the hydrogenation reaction and improves the yield of dimethyl ether.

  4. Selective recovery of dissolved Fe, Al, Cu, and Zn in acid mine drainage based on modeling to predict precipitation pH.

    Science.gov (United States)

    Park, Sang-Min; Yoo, Jong-Chan; Ji, Sang-Woo; Yang, Jung-Seok; Baek, Kitae

    2015-02-01

    Mining activities have caused serious environmental problems including acid mine drainage (AMD), the dispersion of mine tailings and dust, and extensive mine waste. In particular, AMD contaminates soil and water downstream of mines and generally contains mainly valuable metals such as Cu, Zn, and Ni as well as Fe and Al. In this study, we investigated the selective recovery of Fe, Al, Cu, Zn, and Ni from AMD. First, the speciation of Fe, Al, Cu, Zn, and Ni as a function of the equilibrium solution pH was simulated by Visual MINTEQ. Based on the simulation results, the predicted pHs for the selective precipitation of Fe, Al, Cu, and Zn/Ni were determined. And recovery yield of metals using simulation is over 99 %. Experiments using artificial AMD based on the simulation results confirmed the selective recovery of Fe, Al, Cu, and Zn/Ni, and the recovery yields of Fe/Al/Cu/Zn and Fe/Al/Cu/Ni mixtures using Na2CO3 were 99.6/86.8/71.9/77.0 % and 99.2/85.7/73.3/86.1 %, respectively. After then, the simulation results were applied to an actual AMD for the selective recovery of metals, and the recovery yields of Fe, Al, Cu, and Zn using NaOH were 97.2, 74.9, 66.9, and 89.7 %, respectively. Based on the results, it was concluded that selective recovery of dissolved metals from AMD is possible by adjusting the solution pH using NaOH or Na2CO3 as neutralizing agents.

  5. Thermodynamic analysis of the simple microstructure of AlCrFeNiCu high-entropy alloy with multi-principal elements

    Institute of Scientific and Technical Information of China (English)

    Aumin LI; Xiyan ZHANG

    2009-01-01

    AlCrFeNiCu high-entropy alloy (THA) was synthesized by the arc melting and casting method. The alloy exhibits simple FCC and BCC solid solution phases rather than intermetallic compounds. The reason is that the Gibbs free energy of mixing of the equimolar A1CrFeNiCu alloy is smaller than that of inter-metallic compounds by calculation according to the Miedema model.

  6. Nitrite to nitric oxide interconversion by heme FeII complex assisted by [CuI(tmpa)]+

    KAUST Repository

    Turias, Francesc

    2015-09-09

    The present computational study complements the recent experimental efforts by Karlin and coworkers to describe the interconversion of nitrite to nitric oxide by means of an iron porphyrin complex together with a Cu chemical system, i.e., the iron(II) complex (F8TPP)FeII [F8TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2−)] and a preformed copper(II)–nitrito complex [(tmpa)CuII(NO2)][B(C6F5)4] [tmpa = tris(2-pyridylmethyl)amine], being the latter an oxidized species of [(tmpa)CuI(MeCN)]+. By DFT calculations, we unravel how the reduction of nitrite to nitric oxide takes place through a μ-oxo heme-FeIII–O–CuII complex, following a mimetic path as in the cytochrome c oxidase. Mayer bond order (MBO) and energy decomposition analyses are used to analyze the bonding strength of such nitro derivatives to either copper or iron. © 2015 Springer Science+Business Media New York

  7. Ti-Cu-Zr-Fe-Nb ultrafine structure-dendrite composites with good mechanical properties and biocompatibility

    Institute of Scientific and Technical Information of China (English)

    Guan Wang; Shujie Pang; Haifei Li; Min Zhang; Gang Zhou; Tao Zhang

    2013-01-01

    Ti-Cu-Zr-Fe-Nb ultrafine structure-dendrite composites were designed by inducing Nb and more Ti to a Ti-Cu-Zr-Fe glass-forming alloy composition and prepared by copper mold casting. The composite alloys consist ofβ-Ti dendrites and ultrafine-structured CuTi2 and CuTi phases as well as a trace amount of glassy phase. The volume fraction ofβ-Ti dendrites increases with the increase in content of Nb which acted as the β-Ti phase stabilizer in the alloys. The composites exhibit high compressive yield strength exceeding 1200 MPa, maximum strength around 1800 MPa and low Young's modulus around 48 GPa. The plasticity of the alloys is strongly influenced by the volume fraction and morphology of the dendriticβ-Ti phase, and the compressive plastic strain was enlarged from 5.9%for the 4 at%Nb alloy to 9.2%for the 8 at%Nb alloy. The preliminary cell culture experiment indicated good biocompatibility of the composite alloys free from highly toxic elements Ni and Be. These Ti-based composite alloys are promising to have potential structural and biomedical applications due to the combination of good mechanical properties and biocompatibility.

  8. Application of 57Fe Mössbauer spectroscopy as a tool for mining exploration of bornite (Cu5FeS4) copper ore

    Science.gov (United States)

    Gainov, R. R.; Vagizov, F. G.; Golovanevskiy, V. A.; Ksenofontov, V. A.; Klingelhöfer, G.; Klekovkina, V. V.; Shumilova, T. G.; Pen'kov, I. N.

    2014-04-01

    Nuclear resonance methods, including Mössbauer spectroscopy,are considered as unique techniques suitable for remote on-line mineralogical analysis. The employment of these methods provides potentially significant commercial benefits for mining industry. As applied to copper sulfide ores, Mössbauer spectroscopy method is suitable for the analysis noted. Bornite (formally Cu5FeS4) is a significant part of copper ore and identification of its properties is important for economic exploitation of commercial copper ore deposits. A series of natural bornite samples was studied by 57Fe Mössbauer spectroscopy. Two aspects were considered: reexamination of 57Fe Mössbauer properties of natural bornite samples and their stability irrespective of origin and potential use of miniaturized Mössbauer spectrometers MIMOS II for in-situ bornite identification. The results obtained show a number of potential benefits of introducing the available portative Mössbauer equipment into the mining industry for express mineralogical analysis. In addition, results of some preliminary 63,65Cu nuclear quadrupole resonance (NQR) studies of bornite are reported and their merits with Mössbauer techniques for bornite detection discussed.

  9. Effect of Water Vapor During Secondary Cooling on Hot Shortness in Fe-Cu-Ni-Sn-Si Alloys

    Science.gov (United States)

    Sampson, Erica; Sridhar, Seetharaman

    2014-10-01

    Residual Cu in recycled steel scrap can cause hot shortness when the iron matrix is oxidized. Hot shortness can occur directly after the solid steel is formed from continuous casting as the steel undergoes a cooling process known as secondary cooling where water is first sprayed on the surface to promote cooling. This is followed by a radiant cooling stage where the steel is cooled in air to room temperature. This investigation examines the roles of water vapor, Si content, temperature, and the presence of Sn in a Fe-0.2 wt pct Cu-0.05 wt pct Ni alloy on oxidation, separated Cu and Cu induced-hot shortness during simulations of the secondary cooling process. The secondary cooling from 1473 K (1200 °C) resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles at 1423 K (1150 °C) due to the higher temperatures experienced in the non-isothermal cycle. The addition of water vapor increased the sample oxidation as compared to samples processed in dry atmospheres due to increased scale adherence, scale plasticity, and inward transport of oxygen. The increase in weight gain of the wet atmosphere increased the liquid formation at the interface in the non-Si containing alloys. The secondary cooling cycle with water vapor and the effect of Sn lead to the formation of many small pools of Cu-rich liquid embedded within the surface of the metal due to the Sn allowing for increased grain boundary decohesion and the water vapor allowing for oxidation within liquid-penetrated grain boundaries. The presence of Si increased the amount of occlusion of Cu and Fe, significantly decreasing the quantity of liquid at the interface and the amount of grain boundary penetration.

  10. Synthesis and properties of ZnO-HMD@ZnO-Fe/Cu core-shell as advanced material for hydrogen storage.

    Science.gov (United States)

    Bouazizi, N; Boudharaa, T; Bargougui, R; Vieillard, J; Ammar, S; Le Derf, F; Azzouz, A

    2017-04-01

    In this paper, a new synthetic strategy towards functionalized ZnO-HMD@ZnO-Fe/Cu core-shell using sol-gel process modified by chemical grafting of hexamethylenediamine (HMD) on the core and in-situ dispersion of Cu(0)/Fe(0) as metallic nanoparticles (M-NPs) on the shell. The as-prepared core-shell materials were fully characterized by transmission electron microscopy, X-ray powder diffractometry, diffuse reflectance and FT-IR spectrophotometery, photoluminescence, and complexes impedance spectroscopy measurements. The XRD patterns agreed with that of the ZnO typical wurtzite structure, indicating good crystallinity of ZnO-HMD@ZnO-Fe/Cu, with the presence of Fe(0) and Cu(0) phases. Hexamethylenediamine grafting and M-NPs insertion were highly activated and enhanced the core and shell interface by the physiochemical interaction. After functionalization, luminescence intensities and electrical properties of both core and core-shell nanoparticles are improved, indicating the effects of the surface groups on the charge transfer of ZnO-HMD@ZnO-Fe/Cu. The hydrogen capacity retention was depended strongly on the composition and structure of the obtained core-shell. Iron/Copper-loaded ZnO-HMD@ZnO materials exhibited the highest capacity for hydrogen storage. The excellent stability and performance of the ZnO-HMD@ZnO-Fe/Cu core-shell make it an efficient candidate for hydrogen storage.

  11. Photo-degradation of Methyl Orange by Polysaccharides/LaFe0.8Cu0.2O3 Composite Films

    Directory of Open Access Journals (Sweden)

    Aojie Deng

    2014-03-01

    Full Text Available The objective of this work was to prepare a series of composite films (polysaccharides with LaFe0.8Cu0.2O3 for the degradation of methyl orange under ultraviolet irradiation. LaFe0.8Cu0.2O3 was prepared by a sol-gel method, and the composite films were obtained by cross-linking reactions between polysaccharides (xylan and chitosan and LaFe0.8Cu0.2O3. Physical and chemical properties of the composite films were investigated by XRD, FTIR, SEM, and BET. Moreover, the influence of the weight ratio of polysaccharide to LaFe0.8Cu0.2O3 on the methyl orange degradation reaction was also studied. Results showed that 67% of the degradation efficiency was achieved within 480 min using chitosan/LaFe0.8Cu0.2O3 (2:1 as photocatalysts, while 58% was for xylan/LaFe0.8Cu0.2O3 (1:1. The difference was due to the variety in the structure of chitosan and xylan.

  12. Mechanically strong nanocrystalline Fe-Si-B-P-Cu soft magnetic powder cores utilizing magnetic metallic glass as a binder

    Directory of Open Access Journals (Sweden)

    Jian Luan

    2016-05-01

    Full Text Available We report on the fabrication and properties of soft magnetic powder cores with superior mechanical strength as well as low core loss (W. Development of such cores is important for applications in automobiles/devices operating in motion. High saturation magnetic flux density (Bs Fe-Si-B-P-Cu powder was sintered with Fe55C10B5P10Ni15Mo5 metallic glass (MG powder in its supercooled liquid state by spark plasma sintering. The sintered cores are made from the nanocrystalline powder particles of Fe-Si-B-P-Cu alloy, which are separated through a magnetic Fe55C10B5P10Ni15Mo5 MG alloy. Low W of ∼ 2.2 W/kg (at 1T and 50 Hz, and high fracture strength (yielding stress ∼500 MPa, which is an order of magnitude higher than the conventional powder cores, were obtained. Stronger metal-metal bonding and magnetic nature of MG binder (which is very different than the conventional polymer based binders are responsible for the superior mechanical and magnetic properties. The MG binder not only helps in improving the mechanical properties but it also enhances the overall Bs of the core.

  13. GMI Effect Study of Amorphous FeCuNbSiB Multilayered Films%非晶FeCuNbSiB多层膜的巨磁阻抗效应

    Institute of Scientific and Technical Information of China (English)

    Oumarou M; 李晓东; 袁望治; 阮建中; 赵振杰; 杨燮龙

    2005-01-01

    研究在250℃退火温度下非晶FeCuNbSiB薄膜的巨磁阻抗效应.X-ray谱和Mossbauer谱显示样品为非晶状态.导电层的厚度为2 μm,磁性层的厚度为1 μm.三明治结构的最大阻抗效应为20%.为了提高巨磁阻抗效应,在两磁性层之间加入了绝缘层SiO2,在250℃退火温度下最大阻抗效应为62%.随着驱动电流频率的增大,磁阻抗效应曲线由随磁场的单调下降变为出现峰的结构.%Giant magneto-impedance (GMI) has been observed in amorphous FeCuNbSiB/Cu/FeCuNbSiB sandwiched films annealed at 250 ℃. The conductive layer is about 2μm while the outer magnetic layers are about 1 μm thick each. The GMI ratio of 20% has been obtained. In the goal to improve this ratio, two insulator layers have been used between the different layers followed by an annealing process at 250 ℃. A GMI ratio of 62% has been obtained. The displacement of GMI peaks with increasing of driving current frequency appears also. The amorphous state of the films was confirmed by an X-ray diffraction and Mossbauer spectrum.

  14. Fe diffusion in polycrystalline Cu(In,Ga)Se2 layers for thin-film solar cells

    Science.gov (United States)

    Stolwijk, N. A.; Obeidi, Sh.; Bastek, J.; Wuerz, R.; Eicke, A.

    2010-06-01

    Diffusion of Fe in solar-grade Cu(In,Ga)Se2 (CIGSe) layers was investigated over the temperature range from 200 to 600 °C. Either natural or radioactive iron was diffused from the front-surface of CIGSe/Mo/soda lime glass samples. Penetration profiles of stable F56e and radioactive F59e were measured by secondary ion mass spectrometry (SIMS) and ion-beam sputtering in conjunction with activity counting, respectively. The Fe diffusivity can be described by the Arrhenius equation D=1.6×10-4 exp(-0.97 eV/kBT) cm2 s-1. Taking into account Fe solubility data obtained from the SIMS profiles, we provide evidence that D is representative of diffusion along grain boundaries.

  15. Designed synthesis of MOx (M = Zn, Fe, Sn, Ni, Mn, Co, Ce, Mg, Ag), Pt, and Au nanoparticles supported on hierarchical CuO hollow structures.

    Science.gov (United States)

    Zhang, Zailei; Jung, Ji Chul; Yan, Ning

    2016-12-01

    Despite intensive research into support substrates for the dispersal of nanoparticles and their applications, there has been a lack of general methods to produce metal oxide hollow substrates supporting a wide range of metal and metal oxides. Herein, a synthetic protocol for the preparation of CuO hollow structure-supported MOx (M = Zn, Fe, Ni, Sn, Mn, Co, Ce, Mg, and Ag) and noble metals (Pt and Au) with the desired properties and shell structure, such as CuO/Fe2O3, CuO/ZnO, CuO/SnO2, CuO/MgO, CuO/NiO, CuO/Mn2O3, CuO/CoO, CuO/CeO2, CuO/Ag2O, CuO/Pt, CuO/Au hollow cubes, CuO/ZnO double-shell hollow cubes, CuO/SnO2 double-shell hollow octahedra, CuO/SnO2/Fe2O3 and CuO/Mn2O3/NiO double-shell hollow cubes, was developed based on controlled calcination and etching. These hybrid hollow structures were employed not only as support substrates but also as active constituents for catalytic reactions. As an example, we demonstrated that CuO/ZnO hollow cubes are remarkably efficient in converting solid chitin biomass to liquid chemicals in methanol. In addition, CuO/ZnO double-shell hollow cubes were highly effective in the oxidation of benzyl alcohol in the presence of H2O2, whereas CuO/Pt and CuO/Au hollow cubes promoted the oxidation of benzyl alcohol in pure O2. The strategy developed in this work extends the controllable fabrication of high-quality CuO hollow structure-supported nanoparticles using various compositions and shell structures, paving the way to the exploration and systematic comparison of these materials in a wider range of applications.

  16. Mixed valency of Cu, electron-mass enhancement, and three-dimensional arrangement of magnetic sites in the organic conductors (R1,R2-N,N'-dicyanoquinonediimine)2Cu (where R1,R2=CH3,CH3O,Cl,Br)

    Science.gov (United States)

    Kobayashi, H.; Miyamoto, A.; Kato, R.; Sakai, F.; Kobayashi, A.; Yamakita, Y.; Furukawa, Y.; Tasumi, M.; Watanabe, T.

    1993-02-01

    The unique molecular conductors with pπ-d mixing band structures (R1,R2-N,N'-dicyanoquinonediimine)2Cu [(R1,R2-DCNQI)2Cu] (R1,R2=CH3,CH3O,Cl,Br) were examined. General features of the phase diagram of the DCNQI-Cu system were depicted. A region that is related to the existence of anomalously heavy-metal electrons has been found. The T2 dependence of the low-temperature resistivity of the alloyed system (DMe1-xMeBrx-DCNQI)2Cu (where Me=CH3) suggests a large enhancement of the electron mass at the critical situation where the system begins to exhibit a characteristic metal instability. The mixed valency of Cu (Cu+1.3) in (DMe-DCNQI)2Cu was confirmed by ir experiments performed on neutral DMe-DCNQI crystals and (DMe-DCNQI)2M (M=Li, Ba, Cu). The same conclusion was also derived from a low-temperature x-ray-diffraction experiment. The gradual temperature dependences of the ir absorption intensities of totally symmetric modes of (DBr-DCNQI)2Cu observed below the metal-insulator transition temperature (TMI) are in contrast with the discontinuous resistivity and susceptibility changes at TMI. This may be attributable to the existence of two driving forces characterizing the M-I transition. One is the sharp charge ordering in Cu sites and the other is the continuous development of charge-density waves on DCNQI stacks. The arrangement of Cu2+ and Cu+ below TMI was determined by an x-ray crystal-structure analysis of the threefold insulating phase of (MeBr-DCNQI)2Cu at 110 K. The nearest-neighbor Cu2+ ions interact with each other via two DCNQI molecules. A plausible spin structure of the antiferromagnetic ground state was proposed. According to this spin-structure model, the magnetic moments of Cu2+ along the crystallographic c axis will be arranged ferromagnetically.

  17. Catalytic Thermal Decomposition of Ammonium Perchlorate by Cu/Co/Fe Mixed Oxides Derived from Layered Double Hydroxides%Cu/Co/Fe水滑石衍生的复合氧化物催化高氯酸铵热分解的研究

    Institute of Scientific and Technical Information of China (English)

    刘洪博; 黄志勇; 郭冰之; 矫庆泽

    2013-01-01

    Cu/Co/Fe mixed oxides (Cu/Co/Fe-MOs) were prepared by calcining the precursors of Cu/Co/Fe layered double hydroxides (Cu/Co/Fe-LDHs),and were used as new catalysts for the thermal decomposition of ammonium perchlorate (AP).The catalytic activity was investigated using differential thermal analysis (DTA) and thermal gravimetric analyzer coupled with an online mass spectrometer (TG-MS).The results reveal that Cu/Co/Fe-MOs exhibit CuFe2O4 and (CoFe2)O4 phase with high specific surface area of 70~110 m2·g-1.The Cu/Co/Fe-MOs have homogenous particles with crystallite size of 20~30 nm.The thermal decomposition temperature of AP can be lowered by 139 ℃ with 4wt% of Cu/Co/Fe-MOs calcined at 400 ℃.The improvement in thermal decomposition of AP by Cu/Co/Fe-MOs catalysts is achieved via the superoxide ion (O2-) adsorbed on the surface of Cu/Co/Fe-MOs.%以Cu/Co/Fe水滑石(Cu/Co/Fe-LDHs)为前驱体经过焙烧制备了Cu/Co/Fe复合氧化物(Cu/Co/Fe-MOs).利用DTA和TG-MS研究了Cu/Co/Fe-MOs作为新型催化剂对高氯酸铵热分解的催化性能.结果表明,Cu/Co/Fe-MOs呈现为CuFe2O4和(CoFe2)O4晶相,具有70~110 m2·g-1的比表面积.晶粒大小均匀,尺寸在20~30 nm.添加4wt%的400℃焙烧得到的Cu/Co/Fe-MOs催化剂使高氯酸铵热分解反应的温度降低了139℃.Cu/Co/Fe-MOs是通过吸附在金属氧化物表面的超氧离子(O2-)来加速高氯酸铵热分解的.

  18. Microstructure, mechanical, and thermal properties of the Sn-1Ag-0.5Cu solder alloy bearing Fe for electronics applications

    Energy Technology Data Exchange (ETDEWEB)

    Shnawah, Dhafer Abdul-Ameer, E-mail: dhafer_eng@yahoo.com [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Said, Suhana Binti Mohd [Department of Electrical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sabri, Mohd Faizul Mohd; Badruddin, Irfan Anjum [Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Che Faxing [Institute of Microelectronics, A-STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685 (Singapore)

    2012-08-15

    This work investigates the effect of Fe addition on the microstructural, mechanical, and thermal properties of the Sn-1Ag-0.5Cu (SAC105) solder alloy. The addition of Fe leads to the formation of large circular FeSn{sub 2} intermetallic compound (IMC) particles, which produce a weak interface with the {beta}-Sn matrix. The addition of Fe also leads to the inclusion of Fe in the Ag{sub 3}Sn and Cu{sub 6}Sn{sub 5} IMC particles. Moreover, Fe-bearing solders have been shown to form large primary {beta}-Sn grains. The weak interface between the large FeSn{sub 2} IMC particles and the {beta}-Sn matrix together with the presence of the large primary {beta}-Sn grains results in a significant reduction on the elastic modulus and yield strength of the Fe-bearing solders. Moreover, the improved plasticity of the large primary {beta}-Sn grains causes the Fe-bearing solders to exhibit large total elongation. The addition of Fe also significantly reduces the effect of aging. After aging at 100 Degree-Sign C and 180 Degree-Sign C, it has been observed that the Fe-bearing solders significantly suppress the coarsening of the Ag{sub 3}Sn IMC particles; consequently, they exhibit stable mechanical properties. This effect can be attributed to the inclusion of Fe in the Ag{sub 3}Sn IMC particles. In addition, fracture surface analysis indicates that the addition of Fe to the SAC105 solder alloy does not affect the mode of fracture, and all tested solders exhibited large ductile-dimples on the fracture surface. Moreover, the addition of Fe did not produce any significant effect on the melting behavior. As a result, the use conditions of the Fe-bearing solders are consistent with the conditions for conventional Sn-Ag-Cu solder alloys.

  19. Radical scavenging propensity of Cu2 +, Fe3 + complexes of flavonoids and in-vivo radical scavenging by Fe3 +-primuletin

    Science.gov (United States)

    Jabeen, Erum; Janjua, Naveed Kausar; Ahmed, Safeer; Murtaza, Iram; Ali, Tahir; Hameed, Shahid

    2017-01-01

    Cu2 + and Fe3 + complexes of three flavonoids (morin or mo, quercetin or quer and primuletin or prim) were synthesized with the objective of improving antioxidant capacities of flavonoids. The radical scavenging activities of pure flavonoids and their metal complexes were assayed to monitor their tendencies towards sequestering of radicals at physiological conditions. The scavenger potencies of metal-flavonoid complexes were significantly higher than those of the parent flavonoids. Further, influence of the solvent polarity on the radical capturing by flavonoids and their metal complexes was in favor for the polar solvent. Fe3 +-prim displayed its radical scavenging ability via up gradation of CAT and SOD activities in in-vivo antioxidant assays.

  20. Optimization of planar Hall effect sensor for magnetic bead detection using spin-valve NiFe/Cu/NiFe/IrMn structures

    Energy Technology Data Exchange (ETDEWEB)

    Bui Dinh Tu; Do Thi Huong Giang; Tran Mau Danh; Nguyen Huu Duc [Department of Nano Magnetic Materials and Devices, Faculty of Engineering Physics, College of Technology, Vietnam National University, Hanoi (Viet Nam); Le Viet Cuong [Laboratory for Micro-Nano Technology, College of Technology, Vietnam National University, Hanoi (Viet Nam)], E-mail: buidinhtu@vnu.edu.vn

    2009-09-01

    Present paper deals with the planar Hall effect (PHE) of Ta(5 nm)/NiFe(t{sub f})/Cu(1.2 nm)/NiFe(t{sub p})/IrMn(15 nm)/Ta(5 nm) spin-valve structures. Experimental investigations are performed for 50 x 50 {mu}m{sup 2} junctions with various thicknesses of free and pinned layer t{sub f} = 4, 8, 10, 15, 20 nm and t{sub p} = 2, 3, 6, 8, 9, 12 nm. The results show that the thicker free layers, the higher PHE signal is obtained. In addition, the thicker pinned layers, the lower PHE signal. The highest PHE sensitivity S of 15.6 m{omega}/Oe is obtained in the spin-valve configuration with t{sub f} = 20 nm and t{sub p} = 2 nm. This optimum structure is rather promising for micro magnetic bead detections.

  1. Optimization of planar Hall effect sensor for magnetic bead detection using spin-valve NiFe/Cu/NiFe/IrMn structures

    Science.gov (United States)

    Tu, Bui Dinh; Viet Cuong, Le; Thi Huong Giang, Do; Mau Danh, Tran; Duc, Nguyen Huu

    2009-09-01

    Present paper deals with the planar Hall effect (PHE) of Ta(5 nm)/NiFe(tf)/Cu(1.2 nm)/NiFe(tp)/IrMn(15 nm)/Ta(5 nm) spin-valve structures. Experimental investigations are performed for 50 × 50 μm2 junctions with various thicknesses of free and pinned layer tf = 4, 8, 10, 15, 20 nm and tp = 2, 3, 6, 8, 9, 12 nm. The results show that the thicker free layers, the higher PHE signal is obtained. In addition, the thicker pinned layers, the lower PHE signal. The highest PHE sensitivity S of 15.6 mΩ/Oe is obtained in the spin-valve configuration with tf = 20 nm and tp = 2 nm. This optimum structure is rather promising for micro magnetic bead detections.

  2. Microstructure and mechanical properties of spray-deposited Al-Si-Fe-Cu-Mg alloy containing Mn

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Al-20Si-5Fe-3Cu-lMg alloy was synthesized by the spray atomization and deposition technique. The microstructure and mechanical properties of the spray deposited hypereutectic Al-Si alloy were studied using optical microscopy, scanning electron microscopy, X-ray diffraction, TEM (Transmission Electron Microscope) and HREM (High-resolution Electron Microscope), DSC (Differential Scanning Calorimetry), microhardness measurement, and tensile tests. The effects of Mn on the microstructural evolution of the highsilicon aluminum alloy after extrusion and heat treatment have been examined. The results show that two kinds of phases, i.e. S (Al2CuMg) and σ(Al5Cu6Mg2), precipitated from matrix and improved the tensile strength of the alloy efficiently at both the ambient and elevated temperatures (300℃). The tensile test results indicate that the spray-deposited Al-20Si-SFe-3Cu-1Mg alloy has better strength than the powder metallurgy processed Al-20Si-3Cu-1Mg alloy at elevated temperature.

  3. Vibrational spectroscopic and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and the complexes Co{sub 2}L{sub 2}Cl{sub 4}, Cu{sub 2}L{sub 2}Cl{sub 4} and Cu{sub 2}L{sub 2}Br{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Nemcsok, Denes [Institute of General and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellert ter 4, H-1111 Budapest (Hungary); Kovacs, Attila [Hungarian Academy of Sciences, Budapest University of Technology and Economics, Research Group of Technical Analytical Chemistry, Szt. Gellert ter 4, H-1111 Budapest (Hungary)], E-mail: akovacs@mail.bme.hu; Szecsenyi, Katalin Meszaros [Department of Chemistry, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Trg D. Obradovica 3 (Serbia and Montenegro); Leovac, Vukadin M. [Department of Chemistry, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Trg D. Obradovica 3 (Serbia and Montenegro)

    2006-09-29

    In the present paper we report a joint experimental and theoretical study of 3,5-dimethyl-1-thiocarboxamide pyrazole (L) and its complexes Co{sub 2}L{sub 2}Cl{sub 4}, Cu{sub 2}L{sub 2}Cl{sub 4} and Cu{sub 2}L{sub 2}Br{sub 2}. DFT computations were used to model the structural and bonding properties of the title compounds as well as to derive a reliable force field for the normal coordinate analysis of L. The computations indicated the importance of hydrogen bonding interactions in stabilising the global minimum structures on the potential energy surfaces. In contrast to the S-bridged binuclear Cu{sub 2}L{sub 2}Br{sub 2} complex found in the crystal, our computations predicted the formation of (CuLBr){sub 2} dimers in the isolated state stabilized by very strong (53 kJ/mol) N-H...Br hydrogen bonding interactions. On the basis of FT-IR and FT-Raman experiments and the DFT-derived scaled quantum mechanical force field we carried out a complete normal coordinate analysis of L. The FT-IR spectra of the three complexes were interpreted using the present assignment of L, literature data and computed results.

  4. Efficient photocatalytic degradation of rhodamine-B by Fe doped CuS diluted magnetic semiconductor nanoparticles under the simulated sunlight irradiation

    Science.gov (United States)

    Sreelekha, N.; Subramanyam, K.; Amaranatha Reddy, D.; Murali, G.; Rahul Varma, K.; Vijayalakshmi, R. P.

    2016-12-01

    The present work is planned for a simple, inexpensive and efficient approach for the synthesis of Cu1-xFexS (x = 0.00, 0.01, 0.03, 0.05 and 0.07) nanoparticles via simplistic chemical co-precipitation route by using ethylene diamine tetra acetic acid (EDTA) as a capping molecules. As synthesized nanoparticles were used as competent catalysts for degradation of rhodamine-B organic dye pollutant. The properties of prepared samples were analyzed with energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible optical absorption spectroscopy, Fourier transform infrared (FTIR) spectra, Raman spectra and vibrating sample magnetometer (VSM). EDAX spectra corroborated the existence of Fe in prepared nanoparticles within close proximity to stoichiometric ratio. XRD, FTIR and Raman patterns affirmed that configuration of single phase hexagonal crystal structure as that of (P63/mmc) CuS, without impurity crystals. The average particle size estimated by TEM scrutiny is in the assortment of 5-10 nm. UV-visible optical absorption measurements showed that band gap narrowing with increasing the Fe doping concentration. VSM measurements revealed that 3% Fe doped CuS nanoparticles exhibited strong ferromagnetism at room temperature and changeover of magnetic signs from ferromagnetic to the paramagnetic nature with increasing the Fe doping concentration in CuS host lattice. Among all Fe doped CuS nanoparticles, 3% Fe inclusion CuS sample shows better photocatalytic performance in decomposition of RhB compared with the pristine CuS. Thus as synthesized Cu0·97Fe0·03S nanocatalysts are tremendously realistic compounds for photocatalytic fictionalization in the direction of organic dye degradation under visible light.

  5. Evaluation of Antioxidant and Cytotoxicity Activities of Copper Ferrite (CuFe2O4 and Zinc Ferrite (ZnFe2O4 Nanoparticles Synthesized by Sol-Gel Self-Combustion Method

    Directory of Open Access Journals (Sweden)

    Samikannu Kanagesan

    2016-08-01

    Full Text Available Spinel copper ferrite (CuFe2O4 and zinc ferrite (ZnFe2O4 nanoparticles were synthesized using a sol-gel self-combustion technique. The structural, functional, morphological and magnetic properties of the samples were investigated by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, Transmission electron microscopy (TEM and vibrating sample magnetometry (VSM. XRD patterns conform to the copper ferrite and zinc ferrite formation, and the average particle sizes were calculated by using a transmission electron microscope, the measured particle sizes being 56 nm for CuFe2O4 and 68 nm for ZnFe2O4. Both spinel ferrite nanoparticles exhibit ferromagnetic behavior with saturation magnetization of 31 emug−1 for copper ferrite (50.63 Am2/Kg and 28.8 Am2/Kg for zinc ferrite. Both synthesized ferrite nanoparticles were equally effective in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH free radicals. ZnFe2O4 and CuFe2O4 nanoparticles showed 30.57% ± 1.0% and 28.69% ± 1.14% scavenging activity at 125 µg/mL concentrations. In vitro cytotoxicity study revealed higher concentrations (>125 µg/mL of ZnFe2O4 and CuFe2O4 with increased toxicity against MCF-7 cells, but were found to be non-toxic at lower concentrations suggesting their biocompatibility.

  6. Giant magnetoimpedance effect in Fe{sub 75.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 7} ribbon/FeGa film composite

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi, E-mail: yzhang@shnu.edu.cn [Key Laboratory of Optoelectronic Material and Device, Shanghai Normal University, 200234 Shanghai (China); Mathematics & Science College, Shanghai Normal University, 200234 Shanghai (China); Gan, Tao; Wang, Tao [Key Laboratory of Optoelectronic Material and Device, Shanghai Normal University, 200234 Shanghai (China); Wang, Feifei [Mathematics & Science College, Shanghai Normal University, 200234 Shanghai (China); Shi, Wangzhou [Key Laboratory of Optoelectronic Material and Device, Shanghai Normal University, 200234 Shanghai (China); Mathematics & Science College, Shanghai Normal University, 200234 Shanghai (China)

    2016-11-01

    Optimized giant magnetoimpedance effect of Fe{sub 75.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 7} amorphous ribbon/Fe{sub 80}Ga{sub 20} film composites has been investigated. FeCuNbSiB amorphous ribbons as the substrates are commercially available, magnetostrictive FeGa films are deposited on one or both sides of the ribbons by ion-beam sputtering. Compared with the GMI curves without FeGa layer, the GMI effect of FeCuNbSiB amorphous ribbon has been obviously improved with FeGa film covered (from 4% to 16%). Moreover, the details exhibit an interesting phenomenon: at a certain frequency, when the FeGa film covered on one side of the ribbon, the GMI ratio decreases with the thickness of the FeGa film; however, when the FeGa films covered on both sides of the ribbon, the GMI ratio increases with the thickness of the FeGa film. We mainly attribute the reason to strain-induced anisotropy, which is induced by magnetostrictive effect under a longitudinal applied magnetic field. - Highlights: • Magnetostrictive FeGa film is applied to enhance the GMI effect of Fe{sub 75.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 7} amorphous ribbon. • GMI value of Fe{sub 75.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 7} amorphous ribbon/ FeGa film composite is improved from 4% to 16%. • Fe{sub 80}Ga{sub 20} films are deposited on one or both sides of the ribbons by ion-beam sputtering. • Different GMI properties can be observed when FeGa is deposited on one or both sides. • Strain-induced anisotropy of FeGa film could explain this phenomenon.

  7. Simultaneous Cu-, Fe-, and Zn-specific detection of metalloproteins contained in rabbit plasma by size-exclusion chromatography-inductively coupled plasma atomic emission spectroscopy.

    Science.gov (United States)

    Manley, Shawn A; Byrns, Simon; Lyon, Andrew W; Brown, Peter; Gailer, Jürgen

    2009-01-01

    Analytical methods which are capable of determining the plasma or serum metalloproteome have inherent diagnostic value for human diseases associated with increased or decreased concentrations of specific plasma metalloproteins. We have therefore systematically developed a method to rapidly determine the major Cu-, Fe-, and Zn-containing metalloproteins in rabbit plasma (0.5 mL) based on size-exclusion chromatography (SEC; stationary phase Superdex 200, mobile phase phosphate-buffered saline pH 7.4) and the simultaneous online detection of Cu, Fe, and Zn in the column effluent by an inductively coupled plasma atomic emission spectrometer (ICP-AES). Whereas most previous studies reported on the analysis of serum, our investigations clearly demonstrated that the analysis of plasma within 30 min of collection results in the detection of one more Cu peak (blood coagulation factor V) than has been previously reported (transcuprein, ceruloplasmin, albumin-bound Cu, and small molecular weight Cu). The average amount of Cu associated with these five proteins corresponded to 21, 18, 21, 30 and 10% of total plasma Cu, respectively. In contrast, only two Fe metalloproteins (ferritin and transferrin, corresponding to an average of 9 and 91% of total plasma Fe) and approximately five Zn metalloproteins (alpha(2)-macroglobulin and albumin-bound Zn, which corresponded to an average of 10 and 57% of total [corrected] plasma Zn) were detected. Metalloproteins were assigned on the basis of the coelution of the corresponding metal and protein identified by immunoassays or activity-based enzyme assays. The SEC-ICP-AES approach developed allowed the determination of approximately 12 Cu, Fe, and Zn metalloproteins in rabbit plasma within approximately 24 min and can be applied to analyze human plasma, which is potentially useful for diagnosing Cu-, Fe-, and Zn-related diseases.

  8. 曲折型三明治结构FeNi/Cu/FeNi多层膜巨磁阻抗效应研究%Study on giant magneto-impedance effect in FeNi/Cu/FeNi multilayer films with meandering sandwich structure

    Institute of Scientific and Technical Information of China (English)

    夏鹏; 陈磊; 雷剑; 王韬; 周勇

    2011-01-01

    The FeNi/Cu/FeNi multilayer films with meandering sandwich structure were prepared on the glass substrate by using micro electromechanical systems (MEMS) technique. The giant magneto-impedance (GMI) effect was investigated in the current frequency range of 1-40 MHz with external magnetic field Ha applied along the longitudinal axis of the sample. And the effects of sizes of the FeNi film and Cu film on GMI effect were researched through changing their width and thickness. The results show that GMI ratio increases with the increasing of Ha and achieves the positive maximum value at a certain magnetic field strength, then decreases to the negative value with further increase of Ha, When the current frequency is 2 MHz and Ha is 2 kA ·m-1, the positive maximum GMI ratio reaches 169.85%.%采用微机电系统(MEMS)技术在玻璃基片上制备了曲折型三明治结构FeNi/Cu/FeNi多层膜,在电流频率1~40 MHz范围内研究了FeNi/Cu/FeNi多层膜的巨磁阻抗(GMI)效应,并分别通过改变FeNi薄膜的宽度、厚度和Cu薄膜的宽度,研究了尺寸对巨磁阻抗效应的影响,当磁场Ha施加在薄膜的纵轴时,巨磁阻抗变化率随磁场强度的增加而增大,在某一磁场强度下达到最大值,然后随磁场强度的增加而下降到负值.在电流频率为2 MHz,磁场强度为2kA · m-1时,巨磁阻抗变化率达到最大值169.85%.

  9. Synthesis of [MoOS3Cu3U(3,5-diMePy)4]·CH3CN and(Et4N)4[Mo4Cu8O4S12{(Ph2PS)2N}4]from Solid State Product[Et4N]4[Mo2O2S6Cu6I4Br2]%从固相反应产物[NEt4]4[Mo2O2S6Cu6I4Br2]合成原子簇[MoOS3Cu3I(3,5-diMePy)4]·CH3CN和(EtN)4[Mo4Cu8O4S12{(Ph2PS)2}4](英文)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Treatment of iodide-bridged dimer [NEt4] 4[Mo2O2S6Cu6I4Br2] 1 with 3, 5-bimethylpyridine or with K[(Ph2PS) 2N] in CH3CN afforded the tetranuclear cluster [MoOS3Cu3I(3,5-diMePy)4]·CH3CN 2 and dodecanuclear cluster (Et4N)4[Mo4Cu8O4S12{(Ph2PS)2N}4] 3. Monomeric 2 possess a nest-shaped skeleton.The structure of oligomeric 3 can be regarded as a tetramer of nest-shaped MoCu3OS3[(Ph2PS)aN]groups co-polymerized by sharing the limbic Cu atoms.

  10. Modeling hysteresis curves of anisotropic SmCoFeCuZr magnets

    Energy Technology Data Exchange (ETDEWEB)

    Sampaio da Silva, Fernanda A. [Programa de Pos-Graduacao em Engenharia Metalurgica-PUVR, Universidade Federal Fluminense, Av dos Trabalhadores 420, 27255-125 Volta Redonda, RJ (Brazil); Castro, Nicolau A. [Instituto de Pesquisas Tecnologicas, Sao Paulo, SP (Brazil); Campos, Marcos F. de, E-mail: mcampos@metal.eeimvr.uff.br [Programa de Pos-Graduacao em Engenharia Metalurgica-PUVR, Universidade Federal Fluminense, Av dos Trabalhadores 420, 27255-125 Volta Redonda, RJ (Brazil)

    2013-02-15

    The hysteresis curves at room temperature and at 630 K of an anisotropic magnet were successfully modeled with the Stoner-Wohlfarth Callen-Liu-Cullen (SW-CLC) model. This implies that coherent rotation of domains is the reversal mechanism in this magnet. The chemical composition of the evaluated magnet is Sm(Co{sub bal}Fe{sub 0.06}Cu{sub 0.108}Zr{sub 0.03}){sub 7.2}. The anisotropy field H{sub A} was estimated with the model, resulting {mu}{sub 0}H{sub A}=7.1 T at the room temperature, and 2.9 T at 630 K. For this sample, the CLC interaction parameter (1/d) is very low (near zero) and, thus, the nanocrystalline 2:17 grains are well 'magnetically decoupled'. The texture analysis using Schulz Pole figure data indicated M{sub r}/M{sub s} ratio=0.96, and this means that the magnet is very well aligned. The excellent alignment of the grains is one of the reasons for the high coercivity of this sample ({approx}4 T at room temperature). - Highlights: Black-Right-Pointing-Pointer The Stoner-Wohlfarth model can describe the hysteresis curves of anisotropic Sm2Co17 magnets, since the Callen-Liu-Cullen correction is applied. Black-Right-Pointing-Pointer The anisotropy field of the hard magnetic phase Sm2Co17 can be estimated from the hysteresis curves of anisotropic magnets, since the crystallographic texture is known. Black-Right-Pointing-Pointer It is presented a texture study of commercial sintered Sm2Co17 type magnets. Black-Right-Pointing-Pointer The texture data can be used for evaluation of the squareness of the 2nd quadrant of the hysteresis curve, in Sm2Co17 hard coercivity magnets.

  11. Magnetically separable Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposites: Preparation, characterization and visible-light photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chunhua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@whu.edu.cn [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Cao, Qihua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China)

    2015-04-01

    Highlights: • A novel magnetically-separable Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} photocatalyst was in situ prepared. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs had rough and porous chitosan surface layer embedded with Fe{sub 3}O{sub 4} NPs. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed large surface areas and special dimodal pore structure. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed superparamagnetism and could be easily magnetic separated. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited good visible-light photocatalytic activity and stability. - Abstract: A novel magnetically-separable visible-light-induced photocatalyst, Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposite (Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu{sub 2}O was wrapped in chitosan matrix embedded with Fe{sub 3}O{sub 4} nanoparticles. The tight combination of magnetic Fe{sub 3}O{sub 4} and semiconductor Cu{sub 2}O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B

  12. Structure–property relationships along the Fe-substituted CuInS{sub 2} series: Tuning of thermoelectric and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Burnett, Johanna D. [Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States); Gourdon, Olivier [Chemical and Engineering Materials Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); International Centre for Diffraction Data, 12 Campus Boulevard, Newtown Square, PA 19073-3273 (United States); Ranmohotti, Kulugammana G.S.; Takas, Nathan J.; Djieutedjeu, Honore; Poudeu, Pierre F.P. [University of Michigan, Department of Materials Science and Engineering, Laboratory of Emerging Energy and Electronic Materials LE3M, Ann Arbor, MI 48109 (United States); Aitken, Jennifer A., E-mail: aitkenj@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA 15282 (United States)

    2014-09-15

    CuIn{sub 1−x}Fe{sub x}S{sub 2} (x = 0–0.15) was synthesized via high-temperature, solid-state synthesis. Rietveld refinements using the neutron and synchrotron powder diffraction data indicate that all Fe-substituted materials are phase pure with the exception of the CuIn{sub 0.85}Fe{sub 0.15}S{sub 2} sample, which contains a minute secondary phase. These refinements also verify that iron resides on the indium site in the CuIn{sub 1−x}Fe{sub x}S{sub 2} materials. CuIn{sub 0.875}Fe{sub 0.125}S{sub 2} displayed the lowest total thermal conductivity of the series, 1.37 W m{sup −1} K{sup −1} at 570 K, as well as the highest thermopower, −172 μV K{sup −1} at 560 K. The electrical conductivity increases over six times upon going from CuInS{sub 2} to CuIn{sub 0.875}Fe{sub 0.125}S{sub 2}. These improved properties result in an increase in the thermoelectric figure of merit (ZT) of CuInS{sub 2} by over an order of magnitude for the x = 0.125 sample. Magnetic measurements reveal the x = 0–0.10 samples to be paramagnetic, while the sample in which x = 0.125 displays ferromagnetic ordering below 95 K. - Highlights: • Up to 12.5% of the In{sup 3+} is replaced with Fe{sup 3+} in CuInS{sub 2}. • Rietveld refinements using powder diffraction data show iron on the indium site. • CuIn{sub 0.875}Fe{sub 0.125}S{sub 2} is ferromagnetic below 95 K. • The thermal conductivity of CuIn{sub 0.875}Fe{sub 0.125}S{sub 2} is 1.37 W m{sup −1} K{sup −1} at 570 K. • The ZT of CuInS{sub 2} increased by over an order of magnitude with iron substitution.

  13. Copper-promoted circumneutral activation of H2O2 by magnetic CuFe2O4 spinel nanoparticles: Mechanism, stoichiometric efficiency, and pathway of degrading sulfanilamide.

    Science.gov (United States)

    Feng, Yong; Liao, Changzhong; Shih, Kaimin

    2016-07-01

    To evaluate the heterogeneous degradation of sulfanilamide by external energy-free Fenton-like reactions, magnetic CuFe2O4 spinel nanoparticles (NPs) were synthesized and used as catalysts for activation of hydrogen peroxide (H2O2). The physicochemical properties of the CuFe2O4 NPs were characterized with several techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and magnetometry. In the catalytic experiments, CuFe2O4 NPs/H2O2 oxidation showed the best degradation performance in the circumneutral conditions that resulted from the presence of Cu(II) on the surface of the CuFe2O4 NPs. The surface area-normalized pseudo-first-order rate constants were calculated as 2.60 × 10(-2) L m(-1) min(-1), 2.58 × 10(-3) L m(-1) min(-1), 1.92 × 10(-3) L m(-1) min(-1), and 7.30 × 10(-4) L m(-1) min(-1) for CuO, CuFe2O4 NPs, Fe3O4, and α-Fe2O3 catalysts, respectively. Thus, solid state Cu(II) was more reactive and efficient than Fe(III) in the circumneutral activation of H2O2; this finding was further supported by the results regarding the stoichiometric efficiency of H2O2. The effects of experimental parameters such as the oxidant dosage and catalyst loading were investigated. The mechanism for H2O2 activation on the spinel surface was explored and could be explained by the solid redox cycles of Fe(II)/Fe(III) and Cu(II)/Cu(I). Based on the products detected, a degradation pathway via the CS bond cleavage is proposed for the degradation of sulfanilamide. The findings of this study suggest that copper can be used as a doping metal to improve the reactivity and expand the effective pH range of iron oxides.

  14. An aqueous friendly chemosensor derived from vitamin B6 cofactor for colorimetric sensing of Cu2 + and fluorescent turn-off sensing of Fe3 +

    Science.gov (United States)

    Sharma, Darshna; Kuba, Aman; Thomas, Rini; Kumar, Rajender; Choi, Heung-Jin; Sahoo, Suban K.

    2016-01-01

    Chemosensor L derived from vitamin B6 cofactor pyridoxal-5-phosphate was investigated for the selective detection of Cu2 + and Fe3 + in aqueous medium. Sensor L formed a 1:1 complex with Cu2 + and displays a perceptible color change from colorless to yellow brown with the appearance of a new charge transfer band at ~ 450 nm. In contrast, the fluorescence of L was quenched selectively in the presence of Fe3 + without any interference from other metal ions including Cu2 +.

  15. Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors

    Science.gov (United States)

    Jain, Syadwad

    In this study, the localized corrosion and conversion coating on cast alloys 356 (Al-7.0Si-0.3Mg) and 380 (Al-8.5Si-3.5Cu-1.6Fe) were characterized. The intermetallic phases presence in the permanent mold cast alloy 356 are primary-Si, Al5FeSi, Al8Si6Mg3Fe and Mg2Si. The die cast alloy 380 is rich in Cu and Fe elements. These alloying elements result in formation of the intermetallic phases Al 5FeSi, Al2Cu and Al(FeCuCr) along with primary-Si. The Cu- and Fe-rich IMPS are cathodic with respect to the matrix phase and strongly govern the corrosion behavior of the two cast alloys in an aggressive environment due to formation of local electrochemical cell in their vicinity. Results have shown that corrosion behavior of permanent mould cast alloy 356 is significantly better than the die cast aluminum alloy 380, primarily due to high content of Cu- and Fe-rich phases such as Al2Cu and Al 5FeSi in the latter. The IMPS also alter the protection mechanism of the cast alloys in the presence of inhibitors in an environment. The presence of chromate in the solution results in reduced cathodic activity on all the phases. Chromate provides some anodic inhibition by increasing pitting potentials and altering corrosion potentials for the phases. Results have shown that performance of CCC was much better on 356 than on 380, primarily due to inhomogeneous and incomplete coating deposition on Cu- and Fe- phases present in alloy 380. XPS and Raman were used to characterize coating deposition on intermetallics. Results show evidence of cyanide complex formation on the intermetallic phases. The presence of this complex is speculated to locally suppress CCC formation. Formation and breakdown of cerium conversion coatings on 356 and 380 was also analyzed. Results showed that deposition of cerium hydroxide started with heavy precipitation on intermetallic particles with the coatings growing outwards onto the matrix. Electrochemical analysis of synthesized intermetallics compounds in the

  16. Synthesis of nanostructured M/Fe{sub 3}O{sub 4} (M = Ag, Cu) composites using hexamethylentetramine and their electrocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Pan Lu, E-mail: panlu1970@163.com [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China) and Anhui Key Laboratory of Low temperature Co-fired Material, Huainan Normal University, Huainan 232001 (China); Chen Yonghong [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China); Anhui Key Laboratory of Low temperature Co-fired Material, Huainan Normal University, Huainan 232001 (China); Wang Fengwu [Department of Chemistry and Chemical Engineering, Huainan Normal University, Huainan 232001 (China)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer An easily controlled one-step synthesis was designed via a hydrothermal method. Black-Right-Pointing-Pointer Ag/Fe{sub 3}O{sub 4} hybrids and Cu/Fe{sub 3}O{sub 4} nano- and microspheres were successfully synthesized. Black-Right-Pointing-Pointer No surfactant was used in the synthesis. Black-Right-Pointing-Pointer Ag/Fe{sub 3}O{sub 4} hybrids and Cu/Fe{sub 3}O{sub 4} were modified on a GCE directly. Black-Right-Pointing-Pointer The samples all exhibited enhanced catalytic property for p-nitrophenol reduction. - Abstract: Nanoscaled Ag/Fe{sub 3}O{sub 4} hybrids with different Ag contents and Cu/Fe{sub 3}O{sub 4} nanoshpere and microsphere were successfully synthesized with assistance of sodium citrate and (CH{sub 2}){sub 6}N{sub 4} via a hydrothermal process. The as-prepared samples were identified and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and X-ray photoelectron spectroscopy (XPS), respectively. All samples were used as electrocatalysts modified on a glassy carbon electrode for p-nitrophenol reduction in a basic solution. The catalytic activity of Ag/Fe{sub 3}O{sub 4} samples increased first and then decreased by increasing Ag content from 0% to 8%, and the one with 6% Ag displayed the highest catalytic activity. All the Cu/Fe{sub 3}O{sub 4} samples exhibited enhanced catalytic activity by comparison with a glassy carbon electrode, and the one prepared with the molar ratio of Cu{sup 2+}, Fe{sup 3+}, citrate anion, and (CH{sub 2}){sub 6}N{sub 4} with 1:1:3:5 exhibited the highest catalytic activity.

  17. Effect of Cu doping and annealing treatment on the microstructure and magnetic properties of nanocrystalline single-phase Nd-Fe-B alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of Cu addition and annealing treatment on the magnetic properties and microstructure of Nd12.3Fe81.7-xCuxB6 (x=0-1.2 ribbons melt-spun and annealed were systematically investigated by the methods of vibrating sample magnetometer (VSM),X-ray diffraction (XRD),and transmission electron microscopy (TEM).Optimum magnetic properties were achieved by annealing melt-spun Nd12.3Fe81.5Cu0.2B6 ribbons at 550℃ for 15 min,which only contained Nd2Fe14B phase.The remanence,coercive force,and maximum energy product increase by 18.4%,36.2%,and 49% respectively compared with those of Cu-free samples.The significant improvement in magnetic properties originates from the finer grains of the samples by introducing Cu,which leads to the stronger exchange-coupling between neighboring grains.