Ferromagnetism in one-dimensional monatomic metal chains

Gambardella, Pietro; Dallmeyer, A.; Maiti, Kalobaran; Malagoli, M. C.; Eberhardt, W.; Kern, Klaus; Carbone, C.

doi:10.1038/416301a

Cited by 843 publications

(860 citation statements)

References 26 publications

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“…However, our calculated results show that the magnetic anisotropy energy in both [V(Bz)] ∞ and [Mn(Bz)] ∞ polymers is smaller than 0.1 meV/TM, indicating that the ferromagnetism in these polymers might be stabilized only at extremely low temperature by the magnetic anisotropy induced barrier. There are also some reports, indicating the existence of FM in 1D chains with finite length, where the length of the chains is related to the range of the exchange interaction [25]. The most relevant work related to the current study is the discovery of FM in 1D V n (Bz) n+1 sandwich clusters by Miyajima et al [7] as mentioned above.…”

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confidence: 56%

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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We investigate the electronic and magnetic properties of the proposed one-dimensional transition metal (TM=Sc, Ti, V, Cr, and Mn) -benzene (Bz) sandwich polymers by means of density functional calculations. [V(Bz)]∞ is found to be a quasi-half-metallic ferromagnet and half-metallic ferromagnetism is predicted for [Mn(Bz)]∞. Moreover, we show that stretching the [TM(Bz)]∞ polymers could have dramatic effects on their electronic and magnetic properties. The elongated [V(Bz)]∞ displays half-metallic behavior, and [Mn(Bz)]∞ stretched to a certain degree becomes an antiferromagnetic insulator. The possibilities to stabilize the ferromagnetic order in [V(Bz)]∞ and [Mn(Bz)]∞ polymers at finite temperature are discussed. We suggest that the hexagonal bundles composed by these polymers might display intrachain ferromagnetic order at finite temperature by introducing interchain exchange coupling.PACS numbers: 71.20.Rv, 75.75.+a, 82.35.Lr It is expected that the new generation of devices will exploit spin dependent effects, what has been called spintronics [1,2]. A challenge now facing spintronics is transmitting spin signals over long enough distances to allow for spin manipulation. An ideal device for spin-polarized transport should have several key ingredients. First, it should work well at room temperature and should offer as high a magnetoresistance (MR) ratio as possible. In this sense, a half-metallic (HM) ferromagnet with the Curie temperature higher than room temperature is highly desirable since there would be only one electronic spin channel at the Fermi energy [3]. Second, the size or diameter of the materials should be uniform for large scale applications. Carbon nanotubes (CNTs) were considered as promising one-dimensional (1D) spin mediators because of their ballistic nature of conduction and relatively long spin scattering length (at least 130 nm) [4,5]. Coherent spin transport has been observed in multiwalled CNT systems with Co electrodes. The maximum MR ratio of 9% was observed in multiwalled CNTs at 4.2 K. However, as the temperature increases to 20 K, the MR ratio goes to zero, preventing any room temperature applications [4]. A theoretical work suggested that the ferromagnetic (FM) transition-metal (TM) /CNT hybrid structures may be used as devices for spin-polarized transport to further increase the MR ratio [6]. Unfortunately, although large spin polarization is found in these systems, there is no HM behavior. Another difficulty with CNT is that the devices are unlikely to be very reproducible due to the wide assortment of tube size and helicity that is produced during synthesis. Wide variation in device behavior was reported in the CNT experiment [4].Recently, an experimental study suggested that the unpaired electrons on the metal atoms couple ferromagnetically in the multidecker organometallic sandwich Vbenzene (Bz) complexes, i.e., V n (Bz) n+1 clusters [7]. The FM sandwich clusters are supposed to serve as nanomagnetic building blocks in applications such as recording media or spintronic de...

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confidence: 56%

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

et al. 2006

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“…In their pioneering experiments 3 Gambardella et al demonstrated ferromagnetic order and enhanced magnetic anisotropy of monoatomic Co chains on a stepped Pt͑111͒ surface. Numerous theoretical studies followed this experiment, focusing primarily on the unusual magnetic anisotropy in this particular system.…”

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confidence: 99%

Magnetic order and exchange interactions in monoatomic3dtransition-metal chains

et al. 2007

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Based on first-principles calculations we analyze the magnetic order and the exchange interactions in monoatomic 3d transition-metal chains of V, Cr, Mn, Fe, and Co. While freestanding Fe and Co chains remain ferromagnetic in the entire range of interatomic distances, V, Cr, and Mn chains change their magnetic state from antiferromagnetic ͑AFM͒ to ferromagnetic ͑FM͒ upon stretching. The corresponding distance-dependent exchange interaction is in striking resemblance to the Bethe-Slater curve. We demonstrate that in combination with the symmetry reduction on the ͑110͒ surfaces of Cu, Pd, Ag, and NiAl even a weak chain-surface hybridization is sufficient to dramatically change the magnetic coupling in the chains. In particular, we find a tendency towards antiferromagnetic coupling. The obtained magnetic state of a specific chain depends sensitively on the chemical composition and the lattice constant of the surface. Surprisingly, Cr and Mn chains show a transition from ferromagnetic coupling in freestanding chains to antiferromagnetic coupling on the ͑110͒ surfaces of Pd, Ag, and NiAl. For Fe and Co chains on NiAl͑110͒ the FM and AFM states differ by only 2 meV, suggesting the possibility of a more complex, noncollinear magnetic ground state.

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“…This is a necessary (although not sufficient) condition for the emergence of intriguing magnetic properties induced by the low dimensionality, such as giant magnetic anisotropy. [28,29] Because of their high thermal stability, MOCNs similar to those presented here could thus be convenient model systems where to explore the occurrence of low-dimensional magnetism.…”

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Templated Growth of Metal–Organic Coordination Chains at Surfaces

et al. 2005

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Metal-organic coordination networks (MOCNs) formed by coordination bonding between metallic centers and organic ligands can be efficiently engineered to exhibit specific magnetic, electronic, or catalytic properties. [1][2][3][4][5][6] Instead of depositing prefabricated MOCNs onto surfaces, it has been recently shown that two dimensional (2D) MOCNs can be directly grown at metal surfaces in ultra high vacuum (UHV), thus creating highly regular 2D networks of metal atoms. [7][8][9][10][11][12] These grids have been pointed out to be potentially relevant for devices involving sensing, switching, and information storage. [13,14] We show here that this approach offers the additional advantage to predefine the MOCN geometry by using the substrate as template to direct the formation of novel 1D metal-organic coordination chains (MOCCs).The templating role of substrates is well known in the field of surface epitaxial growth. [15][16][17][18][19] Among the highly anisotropic substrates, the Cu(110) surface is one of the most common (Figure 1a and b). In order to evidence its strong 1D templating effect on organic molecules, a ligand with a triangular symmetry was selected: 1,3,5-benzenetricarboxylic acid (trimesic acid, TMA, Figure 1c). In fact, the 3-fold rotation symmetry supports the formation of hexagonal 2D and 3D architectures, [20][21][22] therefore strongly disfavoring the linear geometry. On the isotropic Cu(100) surface, TMA forms 0D carboxylate complexes and 2D networks. [9,10] The UHV deposition of TMA on Cu(110) at 300 K results in the formation of 1D chains along the 110 direction, as observed by STM. This deposition temperature is high enough to * * The authors wish to acknowledge Nian Lin, Magalí Lingenfelder, Alexander Schneider and Giacinto Scoles for fruitful discussions, HPC-EUROPA (project #506079) and INFM Progetto Calcolo Parallelo for computer resources.

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Ferromagnetism in one-dimensional monatomic metal chains

Cited by 843 publications

References 26 publications

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

One-Dimensional Transition Metal−Benzene Sandwich Polymers: Possible Ideal Conductors for Spin Transport

Magnetic order and exchange interactions in monoatomic3dtransition-metal chains

Templated Growth of Metal–Organic Coordination Chains at Surfaces

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