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Influence of Fluorine Substitution on the Properties of Metal Chelate Compounds

Description: From introduction: "This is the first of three articles dealing with the influence of fluorine substitution in the ligand on the properties of metal chelate compounds. Although the primary purpose of this project was to study the influence of fluorine substitution on the properties -- particularly light absorption -- of uranyl compounds, copper chelates were chosen for preliminary study as model substances, because they are easily prepared."
Date: June 9, 1955
Creator: Belford, R. Linn; Martell, Arthur E. & Calvin, Melvin
Partner: UNT Libraries Government Documents Department

The Effect of Temperature on the Distribution of Nitric Acid Between Dibutyl Carbitol and Aqueous Solutions of Copper Nitrate

Description: This report follows a test made to determine the effect of temperature on the distribution of nitric acid between "carbitol" and gunk, extracting a number of samples of aqueous copper nitrate with samples of "carbitol" of various acidities. The data obtained is covered in Table 1.
Date: January 17, 1946
Creator: Shacklett, C. D. & Wilcox, W. J., Jr.
Partner: UNT Libraries Government Documents Department

The Metal-Organic Chemical Vapor Deposition of Cu(II)-bishexafluoroacetylacetonate on a Tungsten Substrate

Description: Evidence is reported for the formation of carbon-containing contamination products at the copper-tungsten (Cu-W) interface during the metal organic chemical vapor deposition (MOCVD) of copper on tungsten. Cu(II)bishexafluoroacetylacetonate [Cu(hfac)_2] was physisorbed onto lightly oxidized tungsten (WO_x) at 115K, under ultra-high vacuum conditions, and then annealed sequentially to higher temperatures. Copper reduction was observed by 320K. Carbonaceous and carbidic contamination of the WO_x surface was observed, even after sample warming to 625K in UHV. The results indicate that low temperature MOCVD of Cu may be possible, but interfacial contamination from the organic ligand fragmentation is a major concern.
Date: May 1992
Creator: Welton, Theresa E. (Theresa Eilene)
Partner: UNT Libraries

Observation of the Fulde-Ferrell-Larkin-Ovchinnikov state in {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}

Description: Magnetic measurements show that the quasi-two-dimensional superconductor {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} enters a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state below {approximately} 5.5 K in exactly in-plane magnetic fields {approximately} 19--24 T.
Date: August 22, 2000
Creator: Symington, J. A.; Singleton, J.; Nam, M.-S.; Ardavan, A.; Kurmoo, M.; Schlueter, J. A. et al.
Partner: UNT Libraries Government Documents Department

Effect of Cu(NO₃)₂, TO₂(NO₃)₂ and Fe(NO₃)₃ on the Distribution Coefficients of Nitrate ion in the System Dibutyl Carbitol-Nitric Acid

Description: Introduction: "In this series of experiments a study of the distribution coefficients was made for the dibutyl carbitol-nitric acid system in the range of 1 to 5 normal nitric acid to establish more closely the break in distribution coefficients, found previously, when the acid concentration was increased from 2 to 4 normal. The study was then continued by adding various salting-out agents to the system. It was found that salting-out agents produce a great effect; in fact, they reverse the previously found curves. Although the break occurs in the same place, the more dilute (instead of the more concentrated) the nitric acid, the greater the distribution coefficient of the system."
Date: 1945
Creator: Warren, Buddy & Susano, C. D.
Partner: UNT Libraries Government Documents Department

Magnetically-induced electric polarization in an organo-metallic magnet

Description: The coupling between magnetic order and ferroelectricity has been under intense investigation in a wide range of transition metal oxides. The strongest coupling is obtained in so-called magnetically induced multiferroics where ferroelectricity arises directly from magnetic order that breaks inversion symmetry. However, it has been difficult to find non-oxide based materials in which these effects occur. Here we present a study of copper dimethyl sulfoxide dichloride (CDC), an organometallic quantum magnet containing S =1/1 Cu spins, in which a switchable electric polarization arises from field-tuned magnetic order. Fast magnetic field pulses allow us to perform sensitive measurements of the electric polarization and demonstrate that the electric state is present only if the magnetic order is non-collinear. Furthermore, we show that the electric polarization can be switched in a stunning hysteretic fashion. Because the magnetic order in CDC is mediated by large organic molecules, our study shows that magnetoelectric interactions can exist in this important class of materials, opening the road to designing magnetoelectrics and multiferroics using large molecules as building blocks. Further, we demonstrate that CDC undergoes a magnetoelectric quantum phase transition -the first of its kind, where both ferroelectric and magnetic order emerge simultaneously as a function of magnetic field at very low temperatures.
Date: January 1, 2009
Creator: Zapf, W S; Fabris, F W; Balakirev, F F; Francoual, S M; Kenzelmann, M & Chen, Y
Partner: UNT Libraries Government Documents Department

The Crystal and Molecular Structure of 2, 2' bipyridylglycinatochloro Copper (II) Dihydrate

Description: The three-dimensional x-ray structure of 2,2'-bipyridylglycinatochloro copper(II) dihydrate has been fully refined to a final R factor of 0.081. The bipyridyl and glycine ligands are arranged about the central copper atom in a square planar configuration while the chlorine atom is 2.635 angstroms above this plane directly over the copper atom. This unusually long distance is explained by the positioning of a glycine group on the opposite side of the square plane, resulting in a distorted octahedral arrangement. Also, the chlorine atom is linked to three oxygen atoms via hydrogen bonding, thus stabilizing the distorted octahedral complex.
Date: May 1975
Creator: Neitzel, Conrad J.
Partner: UNT Libraries

Magnetic Properties of Metal(II) Schiff Base Complexes

Description: Ligands prepared from various combinations of aldehydes and ketones with the appropriate aminealcohol were complexed with cupric acetate monohydrate. The complexes with O,NO or N,N,O donor atoms were synthesized to study the influences of the ligand on molecular structure, spin-spin interaction, and on the value of the exchange integral. The magnetic data indicated that of the eight Cu(II) complexes discussed, two behaved differently from known analogous compounds. Cu (benzoylacetone :ethanolamine) was compared to Cu(acac:ethanolamine), and Cu(pyrr:oaminophenol) was compared to Cu(acac:o-aminophenol). Each pair of complexes was postulated to have the same molecular structure. The synthesis and characterization of Mn(pyrr:oaminophenol) 2H2 is also discussed. The following physical data were collected and discussed: elemental analysis, melting point, molecular weight, infrared spectra, electronic spectra, and magnetic susceptibility.
Date: May 1976
Creator: Hines, Mary Katherine
Partner: UNT Libraries

Copper CVD using liquid coinjection of (hfac)Cu(TMVS) and TMVS

Description: Copper chemical vapor deposition using liquid coinjection of the Cu(I) precursor (hfac)Cu(TMVS) along with TMVS has been demonstrated. The coinjection of TMVS with (hfac)Cu(TMVS) stabilizes the Cu precursor until it enters the reaction chamber, allowing for better control of the deposition and faster deposition rates. Using this technique, we have grown films with as-deposited resistivities of 1.86 {plus_minus} 0.04 {mu}{Omega}-cm, independent of film thickness. Deposition rates of well over 100 nm/min are possible. Good step coverage and gap fill down to 0.6 {mu}m lines is demonstrated, with gap fill being limited by the large Cu grain sizes in these films.
Date: December 31, 1994
Creator: Custer, J.S.; Petersen, G.A.; Smith, P.M.; Parmeter, J.E.; Apblett, C.A.; Norman, J.A.T. et al.
Partner: UNT Libraries Government Documents Department

POC-scale testing of an advanced fine coal dewatering equipment/technique: Quarterly technical progress report,January--March 1997

Description: Laboratory centrifugal dewatering tests were conducted to study the effects of anionic and cationic flocculants on filtration of PMCC compliance (low sulfur) and non-compliance (high sulfur) ultrafine coal slurry. The results obtained with compliance coal indicated that use of 30 g/t anionic flocculant reduced filter cake moisture from 32. 3 to 29.0 percent and increased solids recovery by two absolute percentage points. Use of cationic flocculant had no effects on solids recovery but lowered cake moisture to 27 percent at a dosage of 15 g/t. With the non-compliance coal slurry addition of 15 g/t anionic flocculant lowered cake moisture from 30 to 28.5 percent with marginal effects on solids recovery; addition of cationic flocculant reduced cake moisture by one absolute percentage point. Both flocculants showed marginal effects on solids recovery. Laboratory vacuum filter leaf filtration studies showed that use of flocculants considerably increased filtration kinetics. For example, addition of 15 g/t anionic flocculant to the compliance coal slurry increased filtration kinetics by 10 times and addition of 15 g/t.
Date: May 7, 1997
Creator: Tao, D.; Grappo, J.G. & Parekh, B.K.
Partner: UNT Libraries Government Documents Department

Atomic structure of polar ceramic/metal interface: {l_brace}222{r_brace} MgO/Cu

Description: {l_brace}222{r_brace}MgO/Cu is one of the most extensively characterized ceramic/metal interfaces, with atom-probe field-ion-microscopy, Z-contrast scanning-transmission-electron-microscopy (STEM), and spatially-resolved electron-energy-loss-spectroscopy (EELS) measurements recently performed by the present authors, as well as high-resolution electron microscopy (HREM) of this system by others. Atomistic simulations with local density functional theory (LDFT) and molecular dynamics (MD) have been performed to gain additional insight into the structure of this interface. This presentation describes an interface interatomic potential for {l_brace}222{r_brace}MgO/Cu derived from LDFT total energy calculations, and its application to structural properties, including the terminating species, the absence of dislocation standoff, and the symmetry of the interfacial dislocation network.
Date: December 1, 1997
Creator: Benedek, R.; Shashkov, D.A.; Seidman, D.N.; Muller, D.A.; Silcox, J.; Chisholm, M.F. et al.
Partner: UNT Libraries Government Documents Department

Photoelectron Spectroscopy of YbInCu{sub 4}: Direct Testing of Correlated Electron Models

Description: The electronic properties of single crystal YbInCu{sub 4} have been investigated by means of high resolution photoelectron spectroscopy. A first order, isostructural phase transition for YbInCu{sub 4} at T{sub v}=42 K leads to changes in the Kondo temperature of more than an order of magnitude (27 K vs. 400 K). This phase transition and accompanying Kondo temperature change provide the most direct test of the single impurity model (SIM) to date. Particle hole symmetry allows the SIM to be used for Yb compounds as well as Ce heavy fermions with the great advantage that the predicted Kondo resonance is found on the occupied side of the spectral weight function for Yb materials and is thus directly observable in photoemission. The photoemission results are incongruous with the single impurity model predictions for temperature dependence, binding energy and 4f occupancy, encouraging a reevaluation of the single impurity model. The experiments were conducted using the PGM undulator and 4 meter NIM beamlines at SRC. The spectra were taken at photon energies of 40 eV and 90 eV and the combined energy resolution of the analyzer and monochromator was 45- 85 meV.
Date: December 31, 1997
Creator: Joyce, J.J.; Arko, A.J.; Sarrao, J.L. & Fisk, Z.
Partner: UNT Libraries Government Documents Department

Cu(II) - Catalyzed Hydrazine Reduction of Ferrous Nitrate

Description: This report discusses the results of a study of catalyzed hydrazine reduction of ferrous nitrate. It is apparent that there is a substantial reaction between hydrazine and nitrate ion (or nitric acid) to produce HN3 during both the reduction of Fe(III) and during storage at room temperature.
Date: October 15, 2001
Creator: Karraker, D.G.
Partner: UNT Libraries Government Documents Department

Copper (II) Complexes with Deprotonated N-(2-hydroxyethyl)ethylenediamine

Description: This thesis reports the synthesis and characterization of two new copper(II) halide complexes with deprotonated N-(2-hydroxyethyl)ethylenediamine behaving as a bidentate. The magnetic properties of the new copper(II) complexes were studied from room temperature to liquid nitrogen temperatures. The magnetic data show that both complexes exhibit antiferromagnetic interactions with a singlet ground state and a thermally accessible triplet excited state. Magnetic data and infrared spectra indicate the complexes are halogenbridged. Deprotonation at an amine nitrogen is based on the presence of a hydroxyl stretching band in the infrared spectra. Electronic spectra and infrared spectra indicate the complexes are square planar. Elemental analyses, infrared spectra, electronic spectra, electron spin resonance spectra, and magnetic data are reported and discussed.
Date: December 1975
Creator: Miller, Toney G.
Partner: UNT Libraries

Magnetic Properties of Copper (II) Complexes of Schiff Bases

Description: The synthesis and characterization of two new Schiff base copper(II) complexes are reported. These are Cu(acac: 2-amino-l-phenylethanol) and Cu(acac:2-amino-l-butanol). The ligands, derived from acetylacetone and the appropriate aminoalcohol, are dibasic tridentates with 0,N,O donor atoms. The magnetic properties of the complexes were studied at several temperatures between 78 OK and 296 OK. The magnetic moment of Cu(acac:2-amino-l-phenylethanol) varied little with temperature, and that of Cu(acac:2-amino-lbutanol) increased as the temperature was lowered. This is in contrast to the magnetic moment of Cu(acac:ethanolamine), which decreases as the temperature decreases. Molecular weight data, infrared spectra, magnetic data, electronic spectra, and electron spin resonance spectra of both complexes are reported and discussed.
Date: August 1975
Creator: Jones, William James
Partner: UNT Libraries

Magnetic Properties of Copper (II) Complexes of N-(Hydroxyalkyl) Pyrrole-2-Aldimines

Description: In this work magnetic properties of copper(II) complexes on N-(hydroxyalkyl) pyrrole-2-aldimines were investigated by various techniques, one of which was magnetic susceptibility. Magnetic moments are not directly determined experimentally, but magnetic susceptibilities are.
Date: December 1973
Creator: Pauley, Charles Richard
Partner: UNT Libraries

Development of a Boron-Copper Neutron Absorber Composite

Description: This report describes the fabrication of a new boron-copper neutron absorbing material that was developed to meet the upgrading needs of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory. To increase the intensity of the neutron beams from the IPNS, the target uranium was changed from depleted uranium to uranium enriched to 77.5% U-235. To keep the multiplication factor, k(sub eff) (number of fissions in one generation/number of fissions in preceding generation) at a safe level, a new neutron absorber material was needed. The previous materials, boral and cadmium, could not meet the new requirements and a search of the literature showed that no currently available material was acceptable.
Date: May 1991
Creator: Wiencek, T. C.; Thresh, H. R. & Summers, J. R.
Partner: UNT Libraries Government Documents Department

Electronic Transport Properties in Copper Oxides

Description: Oxidation of copper and electronic transport in thermally grown large-grain poly-crystals of non-stoichiometric copper oxides were studied at elevated temperatures. Thermogravimetric copper oxidation was studied in air and oxygen at temperatures between 350 and 100 C. From the temperature-dependence of oxidation rates, three different processes can be identified for the oxidation of copper: bulk diffusion, grain-boundary diffusion, and surface control with whisker growth; these occur at high, intermediate, and low temperatures, respectively. Electrical conductivity measurements as a function of temperature (350 - 1134 C) and pO2 (10(sup⁻⁸-1.0 atm) indicated intrinsic electronic conduction in CuO over the entire range of conditions. Electronic behavior of non-stoichiometric Cu(sub 2)O indicates that the charge defects are doubly ionized oxygen interstitials and holes. The calculated enthalpy of formation of oxygen ((Delta)H(sub O(sub 2))) and the hole conduction energy (E(sub H)) at constant composition for non-stoichiometric Cu2O are 2.0 (plus minus) 0.2 eV and 0.82 (plus minus) 0.02 eV, respectively.
Date: July 1991
Creator: Park, J.-H. & Natesan, K.
Partner: UNT Libraries Government Documents Department

A Twisted Ladder: Relating the Fe Superconductors to the High Tc Cuprates

Description: We construct a 2-leg ladder model of an Fe-pnictide superconductor and discuss its properties and relationship with the familiar 2-leg cuprate model. Our results suggest that the underlying pairing mechanism for the Fe-pnictide superconductors is similar to that for the cuprates.
Date: May 26, 2010
Creator: Berg, E.
Partner: UNT Libraries Government Documents Department

AC susceptibility and critical current in the organic superconductor {kappa}-(ET){sub 2}Cu(NCS){sub 2}

Description: The AC susceptibility (X{prime}, X{double_prime}) has bee measured in a single crystal of the organic superconductor K-(ET){sub 2}Cu(NCS){sub 2} ({Tc} = 9.5 K) as a function of the DC magnetic field, for several frequencies (10 {sup 2} Hz <f <10{sup 4} Hz) and different AC fields (l{mu}T <h{sub dc} <300{mu}T) at fixed temperatures.
Date: May 1, 1994
Creator: Gonzalez, M. A.; Velez, M.; Vicent, J. L.; Schleuter, J.; Williams, J. M. & Crabtree, G. W.
Partner: UNT Libraries Government Documents Department

Interlayer transport in the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br

Description: Interlayer magnetoresistance as a function of field and temperature with fields parallel and perpendicular to current direction in the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Br was measured. For H{parallel}I, the isothermal magnetoresistance R(H) displays a peak effect as a function of field. For H{perpendicular}I, R(H) increases monotonically with field. Comparison of the peak field with the H{sub c2}(T) data suggests that the peak in R(H) occurs in the mixed state. We analyze the data in terms of the resistively shunted Josephson junction model and the density of states fluctuation model.
Date: April 1, 1997
Creator: Zuo, F.; Su, X.; Alexandrakis, G.C.; Schlueter, J.A.; Kelly, M.E. & Williams, J.M.
Partner: UNT Libraries Government Documents Department

Spiral order in Ba{sub 2}CuGe{sub 2}O{sub 7}

Description: The quasi 2-D square-lattice antiferromagnet Ba{sub 2}CuGe{sub 2}O{sub 7} was studied by neutron scattering and bulk magnetic techniques. An incommensurate magnetic spiral structure with the propagation vector (1+{xi}, 1+{xi}, 0)({xi}=0.027) was observed below T{sub N}=3.26 K. Spin dynamics can be adequately described by conventional spin-wave theory with two exchange constants: nearest- neighbor in-plant antiferromagnetic coupling J{sub 1}{approx}0.48 meV and interplane ferromagnetic interaction J{sub 3}{approx}0.013 meV. This set of exchange parameters apparently fails to explain the spiral order. The non-centrosymmetric crystal structure suggests that the incommensurate phase may be the result of a Dzyaloshinskii-Moriya instability of the Neel ground state.
Date: August 1, 1996
Creator: Zheludev, A.; Shirane, G.; Sasago, Y.; Koide, N. & Uchinokura, K.
Partner: UNT Libraries Government Documents Department

Investigation of Syngas Interaction in Alcohol Synthesis Catalysts

Description: This report presents the work done on Investigation of Syngas Interaction in Alcohol Synthesis Catalysts during the last quarter. FTIR absorption studies on Cu/Co/Cr catalysts using CO as a probe molecule are presented in this report. The aim of this study is to investigate the nature of infrared adsorption of CO on copper-cobalt-chromia catalysts. The chemisorption of CO on metal particles can be associative/dissociative depending upon the nature of the metal, the type of exposed faces and adsorption temperature. Several investigators [1-3], classified cobalt as a border line element which under particular conditions can dissociate CO. For instance the (0001) face of CO is known to be inactive for CO dissociation at room temperature, while the stepped (1012) face is active at very moderate temperatures [4-5] with formation of surface carbide. Of the dissociated species carbon could form a surface carbide and simultaneously the oxygen could form a surface oxide.
Date: September 1, 1997
Partner: UNT Libraries Government Documents Department