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Goikoetxea I, Alducin M, Díez Muiño R, Juaristi JI. The dynamics of adsorption and dissociation of N2 in a monolayer of iron on W(110). Phys Chem Chem Phys 2015; 17:19432-45. [DOI: 10.1039/c5cp02051d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Does N2 adsorption increase on strained Fe monolayers?
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Affiliation(s)
- I. Goikoetxea
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU)
- 20018 Donostia-San Sebastián
- Spain
| | - M. Alducin
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU)
- 20018 Donostia-San Sebastián
- Spain
- Donostia International Physics Center (DIPC)
- 20018 Donostia-San Sebastián
| | - R. Díez Muiño
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU)
- 20018 Donostia-San Sebastián
- Spain
- Donostia International Physics Center (DIPC)
- 20018 Donostia-San Sebastián
| | - J. I. Juaristi
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU)
- 20018 Donostia-San Sebastián
- Spain
- Donostia International Physics Center (DIPC)
- 20018 Donostia-San Sebastián
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Stolbov S, Alcántara Ortigoza M. Rational Design of Competitive Electrocatalysts for Hydrogen Fuel Cells. J Phys Chem Lett 2012; 3:463-467. [PMID: 26286047 DOI: 10.1021/jz201551e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The large-scale application of one of the most promising clean and renewable sources of energy, hydrogen fuel cells, still awaits efficient and cost-effective electrocatalysts for the oxygen reduction reaction (ORR) occurring on the cathode. We demonstrate that truly rational design renders electrocatalysts possessing both qualities. By unifying the knowledge on surface morphology, composition, electronic structure, and reactivity, we solve that trimetallic sandwich-like structures are an excellent choice for optimization. Their constituting species are expected to couple synergistically yielding reaction-environment stability, cost-effectiveness, and tunable reactivity. This cooperative-action concept enabled us to predict two advantageous ORR electrocatalysts: Pd/Fe/W(110) and Au/Ru/W(110). Density functional theory calculations of the reaction free-energy diagrams suggest that these materials are more active toward ORR than the so-far best Pt-based catalysts. Our designing concept advances also a general approach for engineering advanced materials.
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Affiliation(s)
- Sergey Stolbov
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
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Martin DS, Zeybek O, Weightman P, Barrett SD. Optical reflectance anisotropy of the growth of Fe monolayers on W(110). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:355002. [PMID: 21778568 DOI: 10.1088/0953-8984/23/35/355002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report measurements of the optical anisotropy of Fe layers grown on the W(110) surface using reflection anisotropy spectroscopy (RAS). As the first monolayer of Fe is deposited onto W(110), the resonance-like RAS profile of the clean surface is reduced in intensity. We find evidence for the surface state on W(110) surviving as an interface state following Fe deposition. We observe an anisotropic optical response from Fe layers grown on top of the first two monolayers, where a broad peak at 3 eV dominates the RAS response. The results are simulated in terms of a layered Fresnel reflection model incorporating either a strained Fe overlayer or an Fe overlayer whose dielectric properties are approximated by a simple Lorentzian oscillator. Both approaches are found to produce simulated RA spectra that are in good agreement with experiment. The former approach provides evidence that RAS can detect anisotropy in strained overlayers and that 7 ML films have bulk-like electronic and optical properties.
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Affiliation(s)
- D S Martin
- Department of Physics and Surface Science Research Centre, University of Liverpool, Liverpool, L69 7ZE, UK.
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RÖHLSBERGER RALF. MAGNETISM AND LATTICE DYNAMICS OF NANOSCALE STRUCTURES STUDIED BY NUCLEAR RESONANT SCATTERING OF SYNCHROTRON RADIATION. INTERNATIONAL JOURNAL OF NANOSCIENCE 2005. [DOI: 10.1142/s0219581x05003942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nuclear resonant scattering of synchrotron radiation is applied to investigate the magnetic structure and the lattice dynamics of nanoscale systems. The outstanding brilliance of modern synchrotron radiation sources allows for sensitivities to smallest amounts of material. Due to the isotopic sensitivity of the scattering process, ultrathin probe layers of Mössbauer isotopes can be used to map out the magnetic and vibrational structure of thin films with sub-nm spatial resolution. Elastic nuclear resonant scattering is applied to determine the magnetic spin structure of an exchange-coupled bilayer system. Inelastic nuclear resonant scattering was used to determine the vibrational density of states in Fe islands on the W(110) surface.
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Affiliation(s)
- RALF RÖHLSBERGER
- Deutsches Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
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Pratzer M, Elmers HJ. Structural and magnetic properties of Co-Fe binary alloy monolayers on W(110). PHYSICAL REVIEW LETTERS 2003; 90:077201. [PMID: 12633268 DOI: 10.1103/physrevlett.90.077201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2002] [Indexed: 05/24/2023]
Abstract
We present an experimental investigation of CoxFe1-x monolayers grown on flat and stepped W(110) surfaces. Atomically resolved scanning tunneling microscopy and low energy electron diffraction reveal continuous miscibility and pseudomorphic growth of Co and Fe for 0<or=x<0.6. We observe short range ordered CoFe3-p(2x2) and CoFe-c(2x2) structures in the pseudomorphic monolayer. High Co concentrations lead to a phase separation. The Curie temperature and the ferromagnetic Kerr signal at low temperatures decrease monotonically with increasing Co concentration, finally vanishing at x=0.5.
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Affiliation(s)
- M Pratzer
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudingerweg 7, D-55099 Mainz, Germany
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Röhlsberger R, Thomas H, Schlage K, Burkel E, Leupold O, Rüffer R. Imaging the magnetic spin structure of exchange-coupled thin films. PHYSICAL REVIEW LETTERS 2002; 89:237201. [PMID: 12485034 DOI: 10.1103/physrevlett.89.237201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2002] [Indexed: 05/24/2023]
Abstract
We have investigated the magnetic spin structure of a soft-magnetic film that is exchange-coupled to a hard-magnetic layer to form an exchange-spring layer system. The depth dependence of the magnetization direction was determined by nuclear resonant scattering of synchrotron radiation from ultrathin 57Fe probe layers. In an external field a magnetic spiral structure forms that can be described within a one-dimensional micromagnetical model. The experimental method allows one to image vertical spin structures in stratified media with unprecedented accuracy.
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Affiliation(s)
- R Röhlsberger
- Fachbereich Physik, Universität Rostock, August-Bebel-Strasse 55, 18055 Rostock, Germany.
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Röhlsberger R, Bansmann J, Senz V, Jonas KL, Bettac A, Leupold O, Rüffer R, Burkel E, Meiwes-Broer KH. Perpendicular spin orientation in ultrasmall Fe islands on W(110). PHYSICAL REVIEW LETTERS 2001; 86:5597-5600. [PMID: 11415310 DOI: 10.1103/physrevlett.86.5597] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2000] [Indexed: 05/23/2023]
Abstract
We have studied the magnetism of Ag-coated Fe islands on W(110) by nuclear resonant scattering of synchrotron radiation at the 14.4 keV resonance of (57)Fe. Separated islands with an average diameter of 2.0 nm and monolayer thickness are formed at a Fe coverage of theta = 0.57 bulk monolayers. Time spectra of the nuclear decay were measured in the temperature range from 4.5 to 300 K. We find strong evidence for perpendicular spin orientation, which most likely results from the interplay of shape anisotropy and elastic strain in the islands.
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Affiliation(s)
- R Röhlsberger
- Universität Rostock, Fachbereich Physik, Universitätsplatz 3, 18055 Rostock, Germany
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Sander D, Skomski R, Schmidthals C, Enders A, Kirschner J. Film Stress and Domain Wall Pinning in Sesquilayer Iron Films on W(110). PHYSICAL REVIEW LETTERS 1996; 77:2566-2569. [PMID: 10061986 DOI: 10.1103/physrevlett.77.2566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Nomura K, Ujihira Y, Vértes A. Applications of conversion electron Mössbauer spectrometry (CEMS). J Radioanal Nucl Chem 1996. [DOI: 10.1007/bf02037942] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Passek F, Donath M, Ertl K, Dose V. Longer living majority than minority image state at Fe(110). PHYSICAL REVIEW LETTERS 1995; 75:2746-2749. [PMID: 10059394 DOI: 10.1103/physrevlett.75.2746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Chang CR, Chiang YF. Magnetic surface anisotropy of a spin array. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:12783-12788. [PMID: 10007650 DOI: 10.1103/physrevb.48.12783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Wang RW, Mills DL. Spin-wave interactions in the two-dimensional easy-axis Heisenberg ferromagnet. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:3792-3802. [PMID: 10008827 DOI: 10.1103/physrevb.48.3792] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Gerhardter F, Li Y, Baberschke K. Temperature-dependent ferromagnetic-resonance study in ultrahigh vacuum: Magnetic anisotropies of thin iron films. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:11204-11210. [PMID: 10005254 DOI: 10.1103/physrevb.47.11204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Mulhollan GA, Andrews AB, Erskine JL. Layer-dependent spin-polarized 3p core-level photoemission from ultrathin Fe films. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:11212-11215. [PMID: 10003002 DOI: 10.1103/physrevb.46.11212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Erickson RP, Mills DL. Magnetic instabilities in ultrathin ferromagnets. PHYSICAL REVIEW. B, CONDENSED MATTER 1992; 46:861-865. [PMID: 10003270 DOI: 10.1103/physrevb.46.861] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Erickson RP, Mills DL. Thermodynamics of thin ferromagnetic films in the presence of anisotropy and dipolar coupling. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:11825-11835. [PMID: 9999318 DOI: 10.1103/physrevb.44.11825] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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