8,110 research outputs found
Letter to Benjamin Clark Cutler from Benjamin Stevens
No full textLetter dated April 14, 1863 to Assistant Adjutant General, Captain Benjamin Clark Cutler, Santa Fe, from First Lieutenant Benjamin Stevens, Fort Wingate, New Mexico, recommending John Murphy and Martin Quintana, in the First New Mexico Volunteers, for military promotion to Second Lieutenant. Letter also signed by First Lieutenant J. L. Barbey, joint author. Civil War. HL introduction page overlaid by document. Letter in English, handwritten, 1pp/fr
Letter from Benjamin Stevens to W. H. Lewis
No full textLetter dated January 30, 1864 from Benjamin Stevens, Los Pinos, New Mexico, to Captain W. H. Lewis, Santa Fe, declining his, Stevens, commission of Captain in the First Regiment of New Mexico Volunteers. His first term was up soon and it was not worth promoting him for that time. On reverse is confirmation of the decline by Henry Connelly, Governor of New Mexico. New Mexico, military, military appointments. HL introduction page overlaid by document. Letter in English, handwritten, 2pp/fr
Letter to J. C. McFerran from Benjamin Stevens
No full textLetter dated April 12, 1862 from First Lieutenant Benjamin Stevens,First Regiment New Mexico Volunteers, Fort Wingate, New Mexico, to Captain J .C. McFerran, in Santa Fe, asking McFerrin to use his influence in order to secure the promotion of Second Lieutenants John Murphy and Martin Quintana, and gives reason for their promotion. Civil War. HL introduction page overlaid by document. Letter in English, handwritten, 1pp/fr
Investigation of the unusual magnetic properties of Fe and Co on MgO with high spatial, energy and temporal resolution
No full textNanometer-sized magnets are used as magnetic bits in data storage devices to hold information. As such devices are further miniaturized, the control of magnetism at the atomic scale becomes essential. One of the critical parameters to realize nanoscopic magnets is a large magnetic anisotropy. Magnetic anisotropy gives its magnetization a preferred axis and thus its directionality. At the atomic scale, magnetic anisotropy originates from anisotropy in the orbital angular momentum and the spin-orbit coupling that connects the spin moment of a magnetic atom to the spatial symmetry of its ligand field environment. Thus far, the magnetic anisotropy energy per atom in single-molecule magnets and ferromagnetic films remains typically one to two orders of magnitude below the theoretical limit imposed by the atomic spin-orbit interaction. Here we investigate the magnetic properties of individual magnetic atoms on thin magnesium oxide (MgO) films. We find highly unusual magnetic behavior for Fe and Co on the oxygen binding site of MgO. By coordinating a single Co atom to this binding site we can even realized the maximum magnetic anisotropy for a 3d transition metal atom.
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At the heart of this work we combine scanning tunneling microscopy and X-ray absorption spectroscopy experiments and we find striking agreement between these experimental techniques. Scanning tunneling spectroscopy reveals a record-high zero-field splitting of 58 millielectron volts for Co as well as 14 millielectron volts for Fe on the oxygen binding site. This behavior originates from the dominating axial ligand field of this adsorption site, which leads to out-of-plane uniaxial anisotropy combined with large orbital moment, as observed by X-ray magnetic circular dichroism. The bonding geometry and electronic configuration are calculated by density functional theory, a multiplet analysis and a model developed here, that uses a point-charge calculation combined with Stevens operator equivalents. Scanning tunneling microscopy also allows the tuning of the magnetic anisotropy and spin-polarized measurements that confirm the applied model by revealing further transitions and by allowing the measurement of magnetic moments on single atoms.
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A further critical parameter for obtaining miniaturized magnets, for applications in data storage devices, is the magnetic stability, the ability of magnets to retain their magnetic orientation despite external influences. The magnetic stability of larger magnets is determined by a thermal barrier, which scales with the magnetic anisotropy. At the atomic scale, magnetization reversal is often dominated by quantum tunneling of the magnetization. Quantum tunneling allows transitions between states without having to overcome the anisotropy barrier. This is for example caused by mixing between different states, induced by the ligand symmetry. Here we use an all-electrical pump-probe scheme to determine the lifetimes of Co and Fe on MgO and we show how such tunneling can be sufficiently suppressed by careful design of the bonding geometry and by reducing the atom’s interaction with the environment. With this approach, we show the longest lifetimes seen so far for 3d transition metal atoms: a lifetime of 200 microseconds for Co and of 10 milliseconds for Fe.
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The research described in this thesis demonstrates how the complementary use of several experimental and theoretical techniques allows a detailed determination of the character and properties of the magnetic states at the atomic level. These results offer a strategy, based on symmetry arguments and careful tailoring of the interaction with the environment, for the rational design of nanoscopic permanent magnets and single atom magnets
Biographical notes on Benjamin Stevens
No full textRough biographical notes concerning Benjamin Stevens, Kentucky, a mechanic, went to California, life in New Mexico, his personal problems, an affair, marriage, wife, fled, changing his name several times, Civil War service in Army, Valverde, Kit Carson, Indian depredations, story of attack on him and a woman by Navajos, wounded, their escape, friendship with New Mexicans, service in the Legislature, etc. Written by William Gillet Ritch. Document in English, 4 pp/fr, two pages per frame
Fe-Cluster Pushing Electrons to N‑Doped Graphitic Layers with Fe<sub>3</sub>C(Fe) Hybrid Nanostructure to Enhance O<sub>2</sub> Reduction Catalysis of Zn-Air Batteries
No full textNon-noble metal catalysts with catalytic
activity toward oxygen reduction reaction (ORR) comparable or even
superior to that of Pt/C are extremely important for the wide application
of metal–air batteries and fuel cells. Here, we develop a simple
and controllable strategy to synthesize Fe-cluster embedded in Fe3C nanoparticles (designated as Fe3C(Fe)) encased
in nitrogen-doped graphitic layers (NDGLs) with graphitic shells as
a novel hybrid nanostructure as an effective ORR catalyst by directly
pyrolyzing a mixture of Prussian blue (PB) and glucose. The pyrolysis
temperature was found to be the key parameter for obtaining a stable
Fe3C(Fe)@NDGL core–shell nanostructure with an optimized
content of nitrogen. The optimized Fe3C(Fe)@NDGL catalyst
showed high catalytic performance of ORR comparable to that of the
Pt/C (20 wt %) catalyst and better stability than that of the Pt/C
catalyst in alkaline electrolyte. According to the experimental results
and first principle calculation, the high activity of the Fe3C(Fe)@NDGL catalyst can be ascribed to the synergistic effect of
an adequate content of nitrogen doping in graphitic carbon shells
and Fe-cluster pushing electrons to NDGL. A zinc–air battery
utilizing the Fe3C(Fe)@NDGL catalyst demonstrated a maximum
power density of 186 mW cm–2, which is slightly
higher than that of a zinc–air battery utilizing the commercial
Pt/C catalyst (167 mW cm–2), mostly because of the
large surface area of the N-doped graphitic carbon shells. Theoretical
calculation verified that O2 molecules can spontaneously
adsorb on both pristine and nitrogen doped graphene surfaces and then
quickly diffuse to the catalytically active nitrogen sites. Our catalyst
can potentially become a promising replacement for Pt catalysts in
metal-air batteries and fuel cells
Precipitation of supersaturated solute in H ion irradiated Fe-Au and Fe-Au-W alloys studied by positron annihilation spectroscopy
No full textThe effect of thermal aging of homogenized Fe-Au and Fe-Au-W alloys, irradiated at room temperature with hydrogen ions, was studied for an aging treatment at 300 °C for aging times up to 100 h. The aging behavior of the Fe-based alloys is compared to the results for pure Fe. The precipitation behavior of Au-rich and W-rich precipitates and its correlation to the H+ irradiation-induced defects is investigated by variable energy positron annihilation spectroscopy (VEPAS). The formation of open-volume defects after irradiation is monitored by an increase in the S parameter, while the recovery of the vacancy-like defects and the formation of precipitates are signalled by an increase in the W parameter. Au-rich precipitation continuously develops during long-term aging, as indicated by the increase in the W parameter. The change of the W parameter in the Fe-Au-W alloy is not only due to the effect of solute W on the Au precipitates, but also because of the interface of W-rich Laves phase with matrix.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Novel Aerospace MaterialsRST/Fundamental Aspects of Materials and Energ
General Sheman's Visit to Santa Fe
No full textComments on an article by the Jesuits, concerning General Sherman's visit to Santa Fe, from Revista Catolica, October 12, 1878. Fight against the Jesuits, Catholic Church, comment on Bishop Lamy, St. Francis Cathedral, Protestants. Translated from Spanish to English. No sure of author? Document in English, 1 pp/fr, two pages per frame
Notice from Benjamin Stevens to William Frederick Milton Arny
No full textNotice dated March 22, 1866 from Benjamin Stevens, Clerk, Second Judicial District, New Mexico, to William Frederick Milton Arny, requesting a copy of the Compiled Statutes of the Territory of New Mexico. HL introduction page overlaid by document. Notice in English, handwritten, 1pp/fr
Direct promotion effect of Fe on no reduction by activated carbon loaded with Fe species
No full textActivated carbon materials loaded with Fe species were prepared via an impregnation method and studied. Various analyses showed good dispersion of Fe species on the activated carbon surface when the loading amount did not exceed 2 g of iron(III) nitrate nonahydrate on 10 g of activated carbon. Additionally, the simultaneously existing forms of Fe species on the activated samples were found to be Fe3O4, FeO, and elemental Fe(0). NO reduction experiments under anaerobic conditions showed that the loading of Fe species enhanced the NO reducing ability from an NO conversion of (28 to 86)% at 850 degrees C, which is a more remarkable influence on NO reduction than that of the well-known C-O complexes. Thermodynamic analysis and detailed experimental results led to a new mechanism with two independent routes, both of which require Fe participation and proceed at temperatures below and above 800 degrees C, respectively, and generate different COx products. Furthermore, one of the routes was more efficient in reducing NO than the other. This mechanism explained the experiments much better than the existing C-O theory of complexes. (C) 2015 Elsevier Ltd. All rights reserved
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