Showing papers on "Nickel published in 1975"

Calculation of the M 23 magneto-optical absorption spectrum of ferromagnetic nickel

Abstract: The ${M}_{23}$ magneto-optical absorption spectrum of ferromagnetic nickel is calculated using an approach similar to the component state-density method that has been successfully used in obtaining valence-band emission and absorption x-ray spectra of metals. The ${M}_{23}$ magneto-optical effects result predominantly from spin-orbit splitting of the $3p$ core state in conjunction with the final $d$-state spin polarization. The calculated spectrum exhibits features that are directly related to electronic structure parameters including the $3p$ core spin-orbit splitting, and the unfilled $d$-band spin polarization. Temperature variations in the magneto-optical structure can be used to determine separately the exchange-splitting variation and spin-wave excitation contributions to the decrease in the magnetization. Experimental verification of these predictions should provide insight into the applicability of the Stoner model to ferromagnetic nickel and may be helpful in resolving some of the apparently conflicting results of other experimental probes of the spin polarization near the Fermi level in nickel.

New nickel–carbon dioxide complex: synthesis, properties, and crystallographic characterization of (carbon dioxide)-bis(tricyclohexylphosphine)nickel

Abstract: [Ni(CO2)(PCy3)2],0·75(C7H8), where Cy = cyclohexyl, can be made either by treating [Ni(PCy3)3] or [{Ni(PCy3)2}2N2] with CO2 in toluene, or by direct reduction of [NiBr2(PCy3)2] with sodium sand under CO2; the complex is planar, the CO2 ligand possesses bent geometry and is co-ordinated through the carbon atom and one of the oxygen atoms.

Magnetic Properties of Anodic Oxide Coatings on Aluminum Containing Electrodeposited Co and Co‐Ni

Abstract: Cobalt and Co‐Ni alloy were electrodeposited into the micropores of various kinds of anodic oxide films on aluminum. Fine granular metals precipitated on the barrier layer and formed columnar structures. Although the films of cobalt or nickel showed remarkable magnetic anisotropies perpendicular to the surface, the alloy films which consisted of approximately 50% cobalt showed a strong anisotropy along the horizontal direction. Coercive forces ranged from about 500 to about 1100 oe and the density of residual magnetization rose above 1000 gauss. The films may have applications in magnetic memories and recording devices.

High resistivity BaTiO3 ceramics sintered in CO-CO2 atmospheres

Abstract: A barium titanate ceramic containing 13.5 mol % calcium zirconate was doped with up to 3 mol % of oxides of various metals that were considered likely on the basis of ionic size and valence to enter the small cation lattice with charge less than 4+. It was hoped in this way to compensate electrically for loss of oxygen during sintering in CO-CO2 mixtures, so as to obtain high resistivity dielectrics and allow the use of base metal electrodes in a monolithic capacitor. Doping with approximately 0.5 mol % Mn, Co, or Mg produced the highest resistivities, and dielectrics with nickel electrodes and relative permittivity up to 10 000 were obtained with resistivity in excess of 1012 Ω cm at room temperature. When the doped ceramic sintered in contact with nickel, the grain structure and permittivity-temperature characteristics depended on the oxygen partial pressure of the sintering atmosphere, apparently influenced by dissolution of Ni into the ceramic.

Optical constants of copper and nickel as a function of temperature

Abstract: The optical constants were determined for copper and nickel from reflection and transmission measurements on vacuum-evaporated thin films, in the spectral range 0.5-6.5 eV and at temperatures of 78, 293, and 423 K. The imaginary part of the dielectric constant was nearly independent of temperature for nickel, but for copper it increased with temperature in the intraband region below 2 eV and decreased above 4 eV in the interband region. Interpretation of the increase below 2 eV according to the Drude free-electron expression suggests a temperature and frequency dependence of the relaxation time, which is not completely explained. The thermal behavior in the interband region can be largely understood, however, if the zero-temperature theory of Williams, Janak, and Moruzzi is modified by including a Debye-Waller factor in transitions between nearly-free-electron-like bands.

Growth and Structure of Nickel Oxide on Nickel Crystal Faces

Abstract: The structures of films of 300A‐15μ thick formed on (100), (110), and (111)Ni crystal faces at temperatures in the range 500°–800°C were investigated by electron microscopy and x‐ray diffraction. The oxide was initially polycrystalline but rearranged as the oxide thickened to major epitaxial relationships with the metal substrate. These relationships were characterized by coincidence between the close‐packed directions of the metal and oxide; the number and type of oxide orientations were correlated with the number of close‐packed directions in the metal faces. Oxide thicker than 1μ exhibited preferred {100} and {111} orientations. The oxide on (100) and (111)Ni exhibited the highest preferred orientation and a duplex layer structure consisting of equiaxed crystallites in the inner layer and columnar ones in the outer layer. These findings are rationalized in terms of a diffusional model for the growth of these oxide layers in which the reaction rate is determined by boundary and lattice diffusion of nickel through nickel oxide.

Iron-chromium series amorphous alloys

Abstract: Iron-chromium series amorphous alloys having excellent mechanical properties, high heat resistance and corrosion resistance consisting essentially of 1-40 atomic % of chromium, 7-35 atomic % of at least one of carbon, boron and phosphorus and the remainder being iron. In said amorphous alloys, a part of the content of iron may be substituted with at least one sub-component selected from the group consisting of nickel, cobalt, molybdenum, zirconium, titanium, manganese, vanadium, niobium, tungsten, tantalum and copper.