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Liu M, Xin H, Wu Q. Unusual strain effect of a Pt-based L10 face-centered tetragonal core in core/shell nanoparticles for the oxygen reduction reaction. Phys Chem Chem Phys 2019; 21:6477-6484. [DOI: 10.1039/c8cp06756b] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nanoparticles with a low-Pt content core and a few-layer thick Pt skin are attractive catalysts toward the oxygen reduction reaction (ORR) not only for their low cost, but also because their activity can be enhanced by judiciously choosing the core alloy.
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Affiliation(s)
- Mingjie Liu
- Center for Functional Nanomaterials
- Brookhaven National Laboratory
- Upton
- USA
| | - Huolin Xin
- Center for Functional Nanomaterials
- Brookhaven National Laboratory
- Upton
- USA
| | - Qin Wu
- Center for Functional Nanomaterials
- Brookhaven National Laboratory
- Upton
- USA
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2
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Cheng H, Yang N, Lu Q, Zhang Z, Zhang H. Syntheses and Properties of Metal Nanomaterials with Novel Crystal Phases. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707189. [PMID: 29658155 DOI: 10.1002/adma.201707189] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 01/09/2018] [Indexed: 05/13/2023]
Abstract
In recent decades, researchers have devoted tremendous effort into the rational design and controlled synthesis of metal nanomaterials with well-defined size, morphology, composition, and structure, and great achievements have been reached. However, the crystal-phase engineering of metal nanomaterials still remains a big challenge. Recent research has revealed that the crystal phase of metal nanomaterials can significantly alter their properties, arising from the distinct atomic arrangement and modified electronic structure. Until now, it has been relatively uncommon to synthesize metal nanomaterials with novel crystal phases in spite of the fact that these nanostructures would be promising for various applications. Here, the research progress regarding the fine control of noble metal (Au, Ag, Ru, Rh, Pd) and non-noble metal (Fe, Co, Ni) nanomaterials with novel crystal phases is reviewed. First, synthesis strategies and their phase transformations are summarized, while highlighting the peculiar characteristics of each element. The phase-dependent properties are then discussed by providing representative examples. Finally, the challenges and perspectives in this emerging field are proposed.
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Affiliation(s)
- Hongfei Cheng
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Nailiang Yang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Qipeng Lu
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Zhicheng Zhang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Hua Zhang
- Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
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3
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Reduced-dimensionality-induced helimagnetism in iron nanoislands. Nat Commun 2014; 5:5183. [DOI: 10.1038/ncomms6183] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/08/2014] [Indexed: 11/08/2022] Open
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4
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Lounis S. Non-collinear magnetism induced by frustration in transition-metal nanostructures deposited on surfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2014; 26:273201. [PMID: 24918578 DOI: 10.1088/0953-8984/26/27/273201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
How does magnetism behave when the physical dimension is reduced to the size of nanostructures? The multiplicity of magnetic states in these systems can be very rich, in that their properties depend on the atomic species, the cluster size, shape and symmetry or choice of the substrate. Small variations of the cluster parameters may change the properties dramatically. Research in this field has gained much by the many novel experimental methods and techniques exhibiting atomic resolution. Here we review the ab-initio approach, focusing on recent calculations on magnetic frustration and occurrence of non-collinear magnetism in antiferromagnetic nanostructures deposited on surfaces.
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Affiliation(s)
- S Lounis
- Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, 52425 Jülich, Germany
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5
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Bochi G, Ballentine CA, Inglefield HE, Bogomolov SS, Thompson CV, Ohandley RC. Magnetic Anisotropy in Epitaxial Ni/Cu (100) Thin Films. ACTA ACUST UNITED AC 2012. [DOI: 10.1557/proc-313-309] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTEpitaxial Ni/Cu (001) films grown on Si (001) by Molecular Beam Epitaxy were studied in-situ using the Surface Magneto-optic Kerr Effect (SMOKE) and ex-situ with a Vibrating Sample Magnetometer (VSM). Perpendicular Magnetization is observed for Ni thicknesses 15 Å ≤ h ≤ 60 Å and fully in-plane magnetization for h ≥ 70 Å when the films are characterized in-situ. The reversal in magnetic anisotropy observed in-situ at 60 Å shifts to 125 Å when the films are exposed to air. 100 Å Ni films deposited on Cu1−x-Nix alloy substrates also show a reversal in magnetic anisotropy as x is changed. These results suggest that changes in magnetic anisotropy correlate with misfit strain accommodation.
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6
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Amemiya K. Sub-nm resolution depth profiling of the chemical state and magnetic structure of thin films by a depth-resolved X-ray absorption spectroscopy technique. Phys Chem Chem Phys 2012; 14:10477-84. [DOI: 10.1039/c2cp41085k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Schmidt AB, Pickel M, Donath M, Buczek P, Ernst A, Zhukov VP, Echenique PM, Sandratskii LM, Chulkov EV, Weinelt M. Ultrafast magnon generation in an Fe film on Cu(100). PHYSICAL REVIEW LETTERS 2010; 105:197401. [PMID: 21231194 DOI: 10.1103/physrevlett.105.197401] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 08/19/2010] [Indexed: 05/23/2023]
Abstract
We report on a combined experimental and theoretical study of the spin-dependent relaxation processes in the electron system of an iron film on Cu(100). Spin-, time-, energy- and angle-resolved two-photon photoemission shows a strong characteristic dependence of the lifetime of photoexcited electrons on their spin and energy. Ab initio calculations as well as a many-body treatment corroborate that the observed properties are determined by relaxation processes involving magnon emission. Thereby we demonstrate that magnon emission by hot electrons occurs on the femtosecond time scale and thus provides a significant source of ultrafast spin-flip processes. Furthermore, engineering of the magnon spectrum paves the way for tuning the dynamic properties of magnetic materials.
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Affiliation(s)
- A B Schmidt
- Max-Born-Institut, Max-Born-Straße 2A, 12489 Berlin, Germany.
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8
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Pickel M, Schmidt AB, Weinelt M, Donath M. Magnetic exchange splitting in Fe above the Curie temperature. PHYSICAL REVIEW LETTERS 2010; 104:237204. [PMID: 20867266 DOI: 10.1103/physrevlett.104.237204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 02/03/2010] [Indexed: 05/29/2023]
Abstract
The magnetic exchange splitting of electronic states in a 7 monolayer Fe film on Cu(001) was investigated below and above the Curie temperature T(C), using image-potential surface states as sensor. At T(C), the long-range magnetic order breaks down as reflected by a vanishing spin splitting and vanishing spin polarization. The exchange splitting, in contrast, does not change abruptly at T(C) but persists up to T=1.2T(C). Equally, the spin-integrated linewidth shows no signature of the magnetic phase transition but smoothly decreases with increasing temperature. Our experimental results confirm theoretical expectations that, at T(C), the long-range magnetic order disappears but the local magnetic moments and, in particular, the valence electronic structure are unaffected by the phase transition.
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Affiliation(s)
- M Pickel
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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9
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Meyerheim HL, Tonnerre JM, Sandratskii L, Tolentino HCN, Przybylski M, Gabi Y, Yildiz F, Fu XL, Bontempi E, Grenier S, Kirschner J. New model for magnetism in ultrathin fcc Fe on Cu(001). PHYSICAL REVIEW LETTERS 2009; 103:267202. [PMID: 20366339 DOI: 10.1103/physrevlett.103.267202] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Revised: 07/06/2009] [Indexed: 05/27/2023]
Abstract
Using soft-x-ray resonant magnetic scattering in combination with first-principles calculations for noncollinear magnetic configurations we present a new model of the magnetism in ultrathin fcc Fe films on Cu(001). We find the presence of blocks with robust magnetic structure, while the relative directions of the moments of different blocks are sensitive to the detailed atomic structure and temperature. The magnetic noncollinearity is directly demonstrated, which has not been possible so far.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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10
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Sander D, Tian Z, Kirschner J. The role of surface stress in structural transitions, epitaxial growth and magnetism on the nanoscale. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:134015. [PMID: 21817490 DOI: 10.1088/0953-8984/21/13/134015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We review results on combined stress measurements by the crystal curvature technique and structural investigations on different nanoscale systems. It is shown that stress measurements offer highly sensitive and accurate data which identify even subtle structural changes in the sub-monolayer coverage regime. We discuss the unique potential of stress measurements to complement structural investigations of atomic layers and at surfaces. Our examples reveal that stress measurements enhance, support and clarify the interpretation of quantitative structural data. The role of surface stress and film stress for structural transitions in epitaxial growth, surfactant-mediated growth, surface reconstruction and adsorbate-induced spin reorientation transitions in monolayers is discussed.
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Affiliation(s)
- Dirk Sander
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany
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11
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Donath M, Pickel M, Schmidt AB, Weinelt M. Ferromagnetic Fe on Cu(001) throughout the fcc-like phase: arguing from the viewpoint of the electronic structure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:134004. [PMID: 21817479 DOI: 10.1088/0953-8984/21/13/134004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
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?
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Affiliation(s)
- M Donath
- Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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12
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Taroni A, Bramwell ST, Holdsworth PCW. Universal window for two-dimensional critical exponents. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2008; 20:275233. [PMID: 21694394 DOI: 10.1088/0953-8984/20/27/275233] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Two-dimensional condensed matter is realized in increasingly diverse forms that are accessible to experiment and of potential technological value. The properties of these systems are influenced by many length scales and reflect both generic physics and chemical detail. To unify their physical description is therefore a complex and important challenge. Here we investigate the distribution of experimentally estimated critical exponents, β, that characterize the evolution of the order parameter through the ordering transition. The distribution is found to be bimodal and bounded within a window ∼0.1≤β≤0.25, facts that are only in partial agreement with the established theory of critical phenomena. In particular, the bounded nature of the distribution is impossible to reconcile with the existing theory for one of the major universality classes of two-dimensional behaviour-the XY model with four-fold crystal field-which predicts a spectrum of non-universal exponents bounded only from below. Through a combination of numerical and renormalization group arguments we resolve the contradiction between theory and experiment and demonstrate how the 'universal window' for critical exponents observed in experiment arises from a competition between marginal operators.
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Affiliation(s)
- A Taroni
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
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13
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Kurahashi M, Entani S, Yamauchi Y. Surface magnetization measurement with a spin-polarized metastable He beam under high magnetic fields of 0-5 T. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:073902. [PMID: 18681711 DOI: 10.1063/1.2949385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
An apparatus for measuring the surface magnetization with a spin-polarized metastable helium atom (He(*)) beam under external magnetic fields of 0-5 T was developed. The He(*) beam, spin polarized by a sextupole magnet, was directed to the sample placed in the bore of 5 T superconducting magnet. A zero-field spin flipper was used for switching the polarity of beam polarization. A Stern-Gerlach analysis indicated the beam polarization of nearly 100% and the spin flipping efficiency of >90%. A surface magnetization curve was successfully measured from 0 to 5 T for an FeCu(100) surface.
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Affiliation(s)
- Mitsunori Kurahashi
- National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
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14
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Meyerheim HL, Sander D, Negulyaev NN, Stepanyuk VS, Popescu R, Popa I, Kirschner J. Buried Ni/Cu(001) interface at the atomic scale. PHYSICAL REVIEW LETTERS 2008; 100:146101. [PMID: 18518052 DOI: 10.1103/physrevlett.100.146101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Indexed: 05/26/2023]
Abstract
We present a quantitative surface x-ray analysis of the buried Ni/Cu(001) interface structure after deposition of 3 and 5 monolayers of Ni at room temperature. Interface mixing is found where 27+/-10% of top layer Cu atoms are exchanged by Ni. Atomic scale simulations reveal a kinetic pathway for the Ni/Cu-exchange process and explain the observed limited degree of intermixing. A disperse distribution of Ni within the Cu surface with a preferential Ni-Ni separation of 3-4 nearest neighbor distances is determined.
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Affiliation(s)
- H L Meyerheim
- Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D-06120 Halle, Germany.
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15
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Growth Mode and Surface Structure of Cr Ultrathin Film on Fe/Cu(001). E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2008. [DOI: 10.1380/ejssnt.2008.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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CO Adsorption Effects on the Magnetism and Surface Structure of Fe/Cu(001). E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2008. [DOI: 10.1380/ejssnt.2008.233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Choi J, Wu J, Won C, Wu YZ, Scholl A, Doran A, Owens T, Qiu ZQ. Magnetic bubble domain phase at the spin reorientation transition of ultrathin Fe/Ni/Cu(001) film. PHYSICAL REVIEW LETTERS 2007; 98:207205. [PMID: 17677736 DOI: 10.1103/physrevlett.98.207205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 03/01/2007] [Indexed: 05/16/2023]
Abstract
Magnetic domain phases of ultrathin Fe/Ni/Cu(001) are studied using photoemission electron microscopy at the spin reorientation transition (SRT). We observe a new magnetic phase of bubble domains within a narrow SRT region after applying a nearly in-plane magnetic field pulse to the sample. By applying the magnetic field pulse along different directions, we find that the bubble domain phase exists only if the magnetic field direction is less than approximately 10 degrees relative to the sample surface. A temperature dependent measurement shows that the bubble domain phase becomes unstable above 370 K.
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Affiliation(s)
- J Choi
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
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18
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Nakagawa T, Yokoyama T. Magnetic circular dichroism near the Fermi level. PHYSICAL REVIEW LETTERS 2006; 96:237402. [PMID: 16803401 DOI: 10.1103/physrevlett.96.237402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Indexed: 05/10/2023]
Abstract
We report the observation of enhanced magnetic circular dichroism (MCD) near the Fermi level using visible and ultraviolet lasers. More than 10% MCD asymmetry is achieved for a perpendicularly magnetized 12 ML (monolayer) Ni film on Cu(001). By changing the work function with the aid of cesium adsorption, the MCD asymmetry of is found to be enhanced only near the photoemission threshold and to drop down to 0.1% at the photon energy larger than the work function by 0.6 eV. A theoretical calculation also shows enhanced MCD near the photoemission threshold, qualitatively in agreement with the experimental results. Other ultrathin films of 6 ML Ni, 15 ML Co, and 3 and 15 ML Fe on Cu(001) are also investigated. It is found that the perpendicularly magnetized films show much larger MCD asymmetries than the in-plane magnetized films as in the Kerr effect.
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Affiliation(s)
- Takeshi Nakagawa
- Department of Molecular Structure, Institute for Molecular Science, and Department of Structural Molecular Science, The Graduate University for Advanced Studies (Sokendai), Myodaiji-cho, Okazaki, 444-8585, Japan
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19
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Wei B, Shima M, Pati R, Nayak SK, Singh DJ, Ma R, Li Y, Bando Y, Nasu S, Ajayan PM. Room-temperature ferromagnetism in doped face-centered cubic fe nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2006; 2:804-9. [PMID: 17193125 DOI: 10.1002/smll.200500436] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The magnetism of Fe and its alloys has been at the center of scientific and technological interest for decades. Along with the ferromagnetic nature of body-centered cubic Fe, the magnetic properties of face-centered cubic (fcc) Fe have attracted much attention. It is well known that fcc Fe is thermodynamically unstable at ambient conditions and not ferromagnetic. Contrary to what is known, we report that elongated nanoparticles of fcc Fe, grown within graphitic nanotubes, remain structurally stable and appear ferromagnetic at room temperature. The magnetic moment (2+/-0.5 microB) in these nanoparticles and the hyperfine fields for two different components of 57Fe (33 and 21 T), measured by Mössbauer spectroscopy, are explained by carbon interstitials in the expanded fcc Fe lattice, that is, FeC(x) where x approximately 0.10, which result in the formation of a dominant Fe4C stoichiometry. First-principles calculations suggest that the ferromagnetism observed in the fcc Fe is related to both lattice expansion and charge transfer between iron and carbon. The understanding of strain- and dopant-induced ferromagnetism in the fcc Fe could lead to the development of new fcc Fe-based alloys for magnetic applications.
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Affiliation(s)
- Bingqing Wei
- Department of Electrical and Computer Engineering and Center for Computation and Technology, Louisiana State University, Baton Rouge, LA 70803, USA.
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20
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Ibach H, Etzkorn M, Kirschner J. Electron spectrometers for inelastic scattering from magnetic surface excitations. SURF INTERFACE ANAL 2006. [DOI: 10.1002/sia.2425] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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21
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Cr adsorption effect of magnetic property of Fe/Cu(001). E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY 2006. [DOI: 10.1380/ejssnt.2006.345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Jeon YT, Moon JY, Lee GH, Park J, Chang Y. Comparison of the Magnetic Properties of Metastable Hexagonal Close-Packed Ni Nanoparticles with Those of the Stable Face-Centered Cubic Ni Nanoparticles. J Phys Chem B 2005; 110:1187-91. [PMID: 16471662 DOI: 10.1021/jp054608b] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the first magnetic study of pure and metastable hexagonal close-packed (hcp) Ni nanoparticles (sample 1). We also produced stable face-centered cubic (fcc) Ni nanoparticles, as mixtures with the hcp Ni nanoparticles (samples 2 and 3). We compared the magnetic properties of the hcp Ni nanoparticles with those of the fcc Ni nanoparticles by observing the evolution of magnetic properties from those of the hcp Ni nanoparticles to those of the fcc Ni nanoparticles as the number of fcc Ni nanoparticles increased from sample 1 to sample 3. The blocking temperature (T(B)) of the hcp Ni nanoparticles is approximately 12 K for particle diameters ranging between 8.5 and 18 nm, whereas those of the fcc Ni nanoparticles are 250 and 270 K for average particle diameters of 18 and 26 nm, respectively. The hcp Ni nanoparticles seem to be antiferromagnetic for T < T(B) and paramagnetic for T > T(B). This is very different from the fcc Ni nanoparticles, which are ferromagnetic for T < T(B) and superparamagnetic for T > T(B). This unusual magnetic state of the metastable hcp Ni nanoparticles is likely related to their increased bond distance (2.665 angstroms), compared to that (2.499 angstroms) of the stable fcc Ni nanoparticles.
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Affiliation(s)
- Yoon Tae Jeon
- Department of Chemistry, College of Natural Sciences, Kyungpook National University, Taegu 702-701, South Korea
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Torija MA, Li AP, Guan XC, Plummer EW, Shen J. "Live" surface ferromagnetism in Fe nanodots/Cu multilayers on Cu(111). PHYSICAL REVIEW LETTERS 2005; 95:257203. [PMID: 16384502 DOI: 10.1103/physrevlett.95.257203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Indexed: 05/05/2023]
Abstract
We investigate the crossover behavior from two-dimensional (2D) to three-dimensional in multilayers of magnetic nanodots grown by stacking 2D Fe nanodot assemblies on Cu(111) single crystal substrate with a Cu spacing layer. Using an in situ magneto-optical Kerr effect, we have observed a striking ferromagnetic to spin-glass-like phase transition with an increasing number of Fe dot layers. The topmost layer of the Fe dots survives the phase transition and remains ferromagnetic. This unusual surface ferromagnetism is likely caused by a surface-state-mediated coupling which is stronger than the coupling in bulk layers. This is confirmed by the fact that the critical temperature of the surface ferromagnetism is considerably higher than that of the bulk spin-glass phase in the system.
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Affiliation(s)
- M A Torija
- Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Schmidt AB, Pickel M, Wiemhöfer M, Donath M, Weinelt M. Spin-dependent electron dynamics in front of a ferromagnetic surface. PHYSICAL REVIEW LETTERS 2005; 95:107402. [PMID: 16196964 DOI: 10.1103/physrevlett.95.107402] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Indexed: 05/04/2023]
Abstract
Exchange splitting and dynamics of image-potential states in front of a 3 monolayer iron film on Cu(100) have been studied with time-, energy-, and spin-resolved bichromatic two-photon photoemission. For the first image-potential state n=1 we observe an exchange splitting of 56 +/- 10 meV and spin-dependent lifetimes of 16 +/- 2 fs for majority-spin and of 11 +/- 2 fs for minority-spin electrons, respectively. The time-resolved studies of both the population and the linewidth of image-potential states manifest that at the magnetic surface not only inelastic but also quasielastic scattering processes are spin dependent.
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25
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Bernhard T, Baron M, Gruyters M, Winter H. Surface structure of ultrathin Fe films on Cu(001) revisited. PHYSICAL REVIEW LETTERS 2005; 95:087601. [PMID: 16196902 DOI: 10.1103/physrevlett.95.087601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Indexed: 05/04/2023]
Abstract
The structure and magnetism of ultrathin Fe films epitaxially grown on a Cu(001) surface are investigated by grazing scattering of fast H and He atoms or ions. By making use of a new variant of ion beam triangulation based on the detection of the number of emitted electrons, we obtain direct information on the structure of the film surface. We observe for room temperature growth a dominant and defined fcc-like structure. Complex surface reconstructions as reported in recent STM and LEED studies are observed only for cooling and H2 dosing.
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Affiliation(s)
- T Bernhard
- Institut für Physik, Humboldt Universität zu Berlin, Newtonstrasse 15, D-12489 Berlin-Adlershof, Germany
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Torija MA, Gai Z, Myoung N, Plummer EW, Shen J. Frozen low-spin interface in ultrathin Fe films on Cu(111). PHYSICAL REVIEW LETTERS 2005; 95:027201. [PMID: 16090711 DOI: 10.1103/physrevlett.95.027201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Indexed: 05/03/2023]
Abstract
In ultrathin film systems, it is a major challenge to understand how a thickness-driven phase transition proceeds along the cross-sectional direction of the films. We use ultrathin Fe films on Cu(111) as a prototype system to demonstrate how to obtain such information using an in situ scanning tunneling microscope and the surface magneto-optical Kerr effect. The magnetization depth profile of a thickness-driven low-spin to high-spin magnetic phase transition is deduced from the experimental data, which leads us to conclude that a low-spin Fe layer at the Fe/Cu interface stays live upon the phase transition. The magnetically live low-spin phase is believed to be induced by a frozen fcc Fe layer that survives a thickness-driven fcc-->bcc structural transition.
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Affiliation(s)
- M A Torija
- Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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27
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28
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Wu YZ, Won C, Scholl A, Doran A, Zhao HW, Jin XF, Qiu ZQ. Magnetic stripe domains in coupled magnetic sandwiches. PHYSICAL REVIEW LETTERS 2004; 93:117205. [PMID: 15447377 DOI: 10.1103/physrevlett.93.117205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Indexed: 05/24/2023]
Abstract
Magnetic stripe domains in the spin reorientation transition region are investigated in (Fe/Ni)/Cu(001) and Co/Cu/(Fe/Ni)/Cu(001) using photoemission electron microscopy. For (Fe/Ni)/Cu(001), the stripe domain width decreases exponentially as the Fe/Ni film approaches the spin reorientation transition point. For Co/Cu/(Fe/Ni)/Cu(001), the Fe/Ni stripe orientation is aligned with the Co in-plane magnetization, and the stripe domain width decreases exponentially with increasing the interlayer coupling between the Fe/Ni and Co films. By considering magnetic stripes within an in-plane magnetic field, we reveal a universal dependence of the stripe domain width on the magnetic anisotropy and on the interlayer coupling.
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Affiliation(s)
- Y Z Wu
- Department of Physics, University of California Berkeley, Berkeley California 94720, USA
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29
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Bisio F, Terreni S, Gonella G, Floreano L, Morgante A, Canepa M, Mattera L. Temperature driven reversible breakdown of pseudomorphism in ultrathin Fe/Cu3Au films. PHYSICAL REVIEW LETTERS 2004; 93:106103. [PMID: 15447423 DOI: 10.1103/physrevlett.93.106103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Indexed: 05/24/2023]
Abstract
We observe that ultrathin Fe/Cu(3)Au(001) films in the 6-13 A thickness range, beyond the thickness of pseudomorphism breakdown at room temperature, exhibit a temperature dependent structural phase transition in the range T(c) approximately 345-380 K. In the high temperature state the Fe film becomes pseudomorphic, while breakdown of pseudomorphism reversibly occurs as the system is cooled below the transition temperature. The difference between substrate and overlayer thermal expansion coefficient is highlighted as the driving force for the observed transition.
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Affiliation(s)
- F Bisio
- Unità INFM and CNR-IMEM, Dipartimento di Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova, Italy.
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30
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Farnan GA, Fu CL, Gai Z, Krcmar M, Baddorf AP, Zhang Z, Shen J. Electronic stability of magnetic Fe/Co superlattices with monatomic layer alternation. PHYSICAL REVIEW LETTERS 2003; 91:226106. [PMID: 14683255 DOI: 10.1103/physrevlett.91.226106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2003] [Indexed: 05/24/2023]
Abstract
We report a surprising observation that the growth of the [Fe(1 ML)/Co(1 ML)](n) superlattice of L1(0) structure on Cu(100) is stable only up to six atomic layers (n=3), which cannot be rationalized by stress arguments. Instead, first-principles calculations reveal a transition from the L1(0) to the B2 structure due to the effect of dimensionality on the stability of the electronic structure of the superlattice. Whereas the majority-spin electrons are energetically insensitive to the layer thickness, the minority-spin electrons induce the transition at n=3.
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Affiliation(s)
- G A Farnan
- Condensed Matter Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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31
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Portmann O, Vaterlaus A, Pescia D. An inverse transition of magnetic domain patterns in ultrathin films. Nature 2003; 422:701-4. [PMID: 12700756 DOI: 10.1038/nature01538] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2002] [Accepted: 02/21/2003] [Indexed: 11/08/2022]
Abstract
Inverse freezing and inverse melting are processes where a more symmetric phase is found at lower temperatures than at higher temperatures. Such inverse transitions are very rare. Here we report the existence of an inverse transition effect in ultrathin Fe films that are magnetized perpendicular to the film plane. The magnetization of these films is not uniform, but instead manifests itself as stripe domains with opposite perpendicular magnetization. Predictions relating to the disordering of this striped ground state in the limit of monolayer film thicknesses are controversial. Mean-field arguments predict a continuous reduction of the stripe width when the temperature is increased; other studies suggest that topological defects, such as dislocations and disclinations, might penetrate the system and induce geometrical phase transitions. We find, from scanning electron microscopy imaging, that when the temperature is increased, the low-temperature stripe domain structure transforms into a more symmetric, labyrinthine structure. However, at even higher temperatures and before the loss of magnetic order, a re-occurrence of the less symmetric stripe phase is found. Despite the widespread theoretical and experimental work on striped systems, this phase sequence and the microscopic instabilities driving it have not been observed before.
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Affiliation(s)
- O Portmann
- Laboratorium für Festkörperphysik, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland.
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32
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Spisák D, Hafner J. Shear instability of gamma-Fe in bulk and in ultrathin films. PHYSICAL REVIEW LETTERS 2002; 88:056101. [PMID: 11863751 DOI: 10.1103/physrevlett.88.056101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2001] [Indexed: 05/23/2023]
Abstract
Using ab initio local-spin-density calculations we demonstrate that along the Bain path describing the transformation of face-centered-cubic (fcc) gamma-Fe into body-centered-cubic (bcc) alpha-Fe, tetragonal Fe is unstable against monoclinic shear deformations producing a nearly bcc structure. In the limit of a monolayer adsorbed on a fcc substrate, the epitaxial constraint suppresses the shear instability, but in ultrathin films with three to six monolayers a striped pattern of near-bcc domains develops, confirming recent observations by scanning tunneling microscopy. A strong correlation between the shear instability and the magnetic state is reported.
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Affiliation(s)
- D Spisák
- Institut für Materialphysik and Center for Computational Materials Science, Universität Wien, Sensengasse 8/12, A-1090 Wien, Austria
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33
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Surface alloys and alloy surfaces: the platinum-tin system. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1571-0785(02)80093-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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34
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Qian D, Jin XF, Barthel J, Klaua M, Kirschner J. Spin-density wave in ultrathin Fe films on Cu(100). PHYSICAL REVIEW LETTERS 2001; 87:227204. [PMID: 11736424 DOI: 10.1103/physrevlett.87.227204] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2001] [Indexed: 05/23/2023]
Abstract
For Fe films epitaxially grown on Cu(100) at 300 K, the total magnetic moment as a function of film thickness and its temperature dependence have been investigated in situ with a multitechnique approach. The results exclude the collinear type-1 antiferromagnetic configuration as the magnetic structure for face-centered-cubic Fe films on Cu(100). It is proposed that a spin-density-wave state is responsible for the magnetic structure.
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Affiliation(s)
- D Qian
- Surface Physics Laboratory, Fudan University, Shanghai 200433, China
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35
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Biedermann A, Tscheliessnig R, Schmid M, Varga P. Crystallographic structure of ultrathin Fe films on Cu(100). PHYSICAL REVIEW LETTERS 2001; 87:086103. [PMID: 11497964 DOI: 10.1103/physrevlett.87.086103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2001] [Indexed: 05/23/2023]
Abstract
We report the observation of bcc-like crystal structures in 2-4 monolayer (ML) Fe films grown on fcc Cu(100) using scanning tunneling microscopy. The local bcc structure provides a straightforward explanation for their frequently reported outstanding magnetic properties, i.e., ferromagnetic ordering in all layers with a Curie temperature above 300 K. The nonpseudomorphic structure, which becomes pseudomorphic above 4 ML film thickness, is unexpected in terms of conventional rules of thin film growth and stresses the importance of finite thickness effects in ferromagnetic ultrathin films.
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Affiliation(s)
- A Biedermann
- Institut für Allgemeine Physik, Vienna University of Technology, A-1040 Vienna, Austria
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36
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Andrieu S, Chatelain C, Lemine M, Berche B, Bauer P. Size effect on magnetism of Fe thin films in Fe/Ir superlattices. PHYSICAL REVIEW LETTERS 2001; 86:3883-3886. [PMID: 11329348 DOI: 10.1103/physrevlett.86.3883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2000] [Indexed: 05/23/2023]
Abstract
In ferromagnetic thin films, the Curie temperature variation with the thickness is always considered as continuous when the thickness is varied from n to n+1 atomic planes. We show that it is not the case for Fe in Fe/Ir superlattices. For an integer number of atomic planes, a unique magnetic transition is observed by susceptibility measurements, whereas two magnetic transitions are observed for fractional numbers of planes. This behavior is attributed to successive transitions of areas with n and n+1 atomic planes, for which the T(c)'s are not the same. Indeed, the magnetic correlation length is presumably shorter than the average size of the terraces. Monte Carlo simulations are performed to support this explanation.
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Affiliation(s)
- S Andrieu
- Laboratoire de Physique des Matériaux, Université Henri Poincaré, Nancy 1, BP 239, F-54506 Vandoeuvre, France
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37
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Biedermann A, Schmid M, Varga P. Nucleation of bcc iron in ultrathin fcc films. PHYSICAL REVIEW LETTERS 2001; 86:464-467. [PMID: 11177856 DOI: 10.1103/physrevlett.86.464] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2000] [Indexed: 05/23/2023]
Abstract
Needle-shaped bcc nucleation centers in fcc films of Fe on Cu(100) are observed by scanning tunneling microscopy. They form virtually without mass transfer and nearly under conservation of volume, which causes a large strain within the nascent bcc grain. The corresponding strain energy almost equals the gain in structural energy, rendering the bcc nucleation very sensitive to any effect influencing this subtle balance. We suggest that modifying the film by straining, alloying, or surface adsorption may inhibit the bcc nucleation and lead to thick metastable fcc films.
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Affiliation(s)
- A Biedermann
- Institut für Allgemeine Physik, Vienna University of Technology, A-1040 Vienna, Austria
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38
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Camley RE, Li D. Theoretical calculation of magnetic properties of ultrathin Fe films on Cu(100). PHYSICAL REVIEW LETTERS 2000; 84:4709-4712. [PMID: 10990777 DOI: 10.1103/physrevlett.84.4709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/1999] [Indexed: 05/23/2023]
Abstract
The temperature dependence of the magnetization in fcc Fe on Cu(100) is calculated using a self-consistent local mean-field theory. The model reproduces an experimental magnetization oscillation as a function of film thickness and supports a picture where the top two layers are ferromagnetically coupled, and the remaining layers are antiferromagnetically coupled. The origin of the puzzling linear temperature dependence in oscillation amplitude is understood as a "surface phenomena" of the antiferromagnetic layer at the Fe/Cu interface. Proximity effects between a thin antiferromagnet with a low Neel temperature and a neighboring ferromagnet with a higher Curie temperature are discussed.
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Affiliation(s)
- RE Camley
- Department of Physics, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80933-7150, USA
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39
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Vaterlaus A, Stamm C, Maier U, Pini MG, Politi P, Pescia D. Two-step disordering of perpendicularly magnetized ultrathin films. PHYSICAL REVIEW LETTERS 2000; 84:2247-2250. [PMID: 11017255 DOI: 10.1103/physrevlett.84.2247] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/1999] [Indexed: 05/23/2023]
Abstract
We have imaged the stripe domain structure of perpendicularly magnetized fcc ultrathin Fe films grown on Cu(100). The stripe phase has a strong local orientational order and sustains the two kinds of fluctuations predicted by Abanov et al. [Phys. Rev. B 51, 1023 (1995)]: meandering and dislocations. Before reaching the Curie temperature, the stripes transform into a new and so far unobserved domain structure, characterized by domains with predominantly square corners. We argue that this phase is the tetragonal liquid phase proposed by Abanov et al. to separate the stripe phase from the paramagnetic phase. This two-step disordering is reminiscent of a two-dimensional melting process.
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Affiliation(s)
- A Vaterlaus
- Laboratorium für Festkörperphysik, Eidgenössische Technische Hochschule Zürich, CH-8093 Zürich, Switzerland
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40
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Dowben P, McIlroy D, Li D. Chapter 159 Surface magnetism of the lanthanides. HANDBOOK ON THE PHYSICS AND CHEMISTRY OF RARE EARTHS 1997. [DOI: 10.1016/s0168-1273(97)24004-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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41
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Schneider CM, Pracht U, Kuch W, Chassé A, Kirschner J. Magnetic dichroism in photoemission as a spin-resolving probe for electronic correlations. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R15618-R15621. [PMID: 9985716 DOI: 10.1103/physrevb.54.r15618] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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Elmers HJ, Hauschild J, Gradmann U. Critical behavior of the uniaxial ferromagnetic monolayer Fe(110) on W(110). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:15224-15233. [PMID: 9985584 DOI: 10.1103/physrevb.54.15224] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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43
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Lorenz R, Hafner J. Magnetic structure and anisotropy of thin Fe films on Cu(001) substrates. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:15937-15949. [PMID: 9985663 DOI: 10.1103/physrevb.54.15937] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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44
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Dunn JH, Arvanitis D, Mårtensson N. Magnetism of thin Fe films on Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R11157-R11160. [PMID: 9985010 DOI: 10.1103/physrevb.54.r11157] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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Gubanka B, Donath M, Passek F. Magnetically split sp-derived states in fcc-like Fe/Cu(001). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R11153-R11156. [PMID: 9985009 DOI: 10.1103/physrevb.54.r11153] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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46
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Bode M, Pascal R, Dreyer M, Wiesendanger R. Nanostructural and local electronic properties of Fe/W(110) correlated by scanning tunneling spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R8385-R8388. [PMID: 9984601 DOI: 10.1103/physrevb.54.r8385] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Wallauer W, Fauster T. Exchange splitting of image states on Fe/Cu(100) and Co/Cu(100). PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:5086-5091. [PMID: 9986473 DOI: 10.1103/physrevb.54.5086] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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48
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Escorcia-Aparicio EJ, Kawakami RK, Qiu ZQ. fcc Fe films grown on a ferromagnetic fcc Co(100) substrate. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:4155-4158. [PMID: 9986318 DOI: 10.1103/physrevb.54.4155] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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49
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Straub M, Vollmer R, Kirschner J. Surface Magnetism of Ultrathin gamma -Fe Films Investigated by Nonlinear Magneto-optical Kerr Effect. PHYSICAL REVIEW LETTERS 1996; 77:743-746. [PMID: 10062891 DOI: 10.1103/physrevlett.77.743] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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50
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Kirilyuk A, Giergiel J, Shen J, Straub M, Kirschner J. Growth of stabilized gamma -Fe films and their magnetic properties. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:1050-1063. [PMID: 9985373 DOI: 10.1103/physrevb.54.1050] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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