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Liviu F Chibotaru - One of the best experts on this subject based on the ideXlab platform.

  • Dysprosium single molecule magnets with bulky schiff base ligands modification of the slow relaxation of the magnetization by substituent change
    Chemistry: A European Journal, 2019
    Co-Authors: Jerome Long, Liviu F Chibotaru, Ivan V Basalov, Natalia V Forosenko, Konstantin A Lyssenko, Ekaterina Mamontova, Anton V Cherkasov, Marko Damjanovic, Yannick Guari, Joulia Larionova
    Abstract:

    The synthesis, and magnetic and photoluminescence investigations of two bifunctional Dysprosium complexes based on tridentate Schiff base ligands is reported. Magnetic investigations reveal a genuine single-molecule magnet (SMM) behavior, with out-of-phase signals up to 60 K, and tunable emission arising from the Schiff base ligands.

  • magneto structural correlations in arsenic and selenium ligated Dysprosium single molecule magnets
    Chemical Science, 2016
    Co-Authors: Thomas Pugh, Liviu F Chibotaru, Veacheslav Vieru, Richard A Layfield
    Abstract:

    The structures and magnetic properties of the arsenic- and selenium-ligated Dysprosium single-molecule magnets (SMMs) [Cp′3Dy(AsH2Mes)] (3-Dy), [(η5-Cp′2Dy){μ-As(H)Mes}]3 (4-Dy), [Li(thf)4]2[(η5-Cp′2Dy)3(μ3-AsMes)3Li] ([Li(thf)4]2[5-Dy]), and [(η5-Cp′2Dy){μ-SeMes}]3 (6-Dy) are described. The arsenic-ligated complexes 4-Dy and 5-Dy are the first SMMs to feature ligands with metalloid elements as the donor atoms. The arsenide-ligated complex 4-Dy and the selenolate-ligated complex 6-Dy show large anisotropy barriers in the region of 250 cm−1 in zero d.c. field, increasing to 300 cm−1 upon 5% magnetic dilution. Theoretical studies reveal that thermal relaxation in these SMMs occurs via the second-excited Kramers' doublet. In contrast, the arsinidene-ligated SMM 5-Dy gives a much smaller barrier of 23 cm−1, increasing to 35 cm−1 upon dilution. The field-dependence of the magnetization for 4-Dy and 5-Dy at 1.8 K show unusual plateaus around 10 kOe, which is due to the dominance of arsenic-mediated exchange over the dipolar exchange. The effects of the exchange interactions are more pronounced in 5-Dy, which is a consequence of a small but significant increase in the covalent contribution to the predominantly ionic Dysprosium-arsenic bonds. Whereas the magnetically non-dilute Dysprosium SMMs show only very narrow magnetization versus field hysteresis loops at 1.8 K, the impact of magnetic dilution is dramatic, with butterfly-shaped loops being observed up to 5.4 K in the case of 4-Dy. Our findings suggest that ligands with heavier p-block element donor atoms have considerable potential to be developed more widely for applications in molecular magnetism.

  • tuning the magnetic interactions and relaxation dynamics of dy2 single molecule magnets
    Chemistry: A European Journal, 2015
    Co-Authors: Liviu Ungur, Jinkui Tang, Liviu F Chibotaru
    Abstract:

    Efficient modulation of single-molecule magnet (SMM) behavior was realized by deliberate structural modification of the Dy-2 cores of [Dy-2(a'povh)(2)(OAc)(2)(DMF)(2)] (1) and [Zn2Dy2(a'povh)(2)(OAc)(6)]center dot 4H(2)O (2; H(2)a'povh=N'-[amino(pyrimidin-2-yl)methylene]-o-vanilloyl hydrazine). Compound 1 having fourfold linkage between the two Dysprosium ions shows high-performance SMM behavior with a thermal energy barrier of 322.1 K, whereas only slow relaxation is observed for compound 2 with only twofold connection between the Dysprosium ions. This remarkable discrepancy is mainly because of strong axiality in 1 due to one pronounced covalent bond, as revealed by experimental and theoretical investigations. The significant antiferromagnetic interaction derived from bis(mu(2)-O) and two acetate bridging groups was found to be crucial in leading to a nonmagnetic ground state in 1, by suppressing zero-field quantum tunneling of magnetization.

  • influencing the properties of Dysprosium single molecule magnets with phosphorus donor ligands
    Nature Communications, 2015
    Co-Authors: Thomas Pugh, Liviu Ungur, Liviu F Chibotaru, David Collison, Floriana Tuna, Eric J L Mcinnes, Richard A Layfield
    Abstract:

    Ligand design contributes to dictating the magnetic properties of lanthanide-based single-molecule magnets. Here, the authors report a series of phosphorus-ligated Dysprosium complexes, and show that the dynamic magnetic properties change as the ligand is varied from phosphine to phosphide to phosphinidene.

  • chemical tuning of the magnetic relaxation in Dysprosium iii mononuclear complexes
    Dalton Transactions, 2014
    Co-Authors: Luke J Batchelor, Liviu Ungur, Liviu F Chibotaru, Wolfgang Wernsdorfer, Floriana Tuna, Irene Cimatti, Regis Guillot, Victoria E Campbell, Talal Mallah
    Abstract:

    A Dysprosium(III) complex, exhibiting slow relaxation of magnetization, was prepared. Crystallographic studies showed a perturbation of local symmetry upon deprotonation of the ligand, with concomitant faster relaxation of magnetization. This was attributed to a large shift in the direction of the main magnetic axis, as indicated by ab initio calculations.

Jinkui Tang - One of the best experts on this subject based on the ideXlab platform.

  • cis trans isomerism modulates the magnetic relaxation of Dysprosium single molecule magnets
    Chemical Science, 2016
    Co-Authors: Jianfeng Wu, Jinkui Tang, Julie Jung, Haixia Zhang, Peng Zhang, Boris Le Guennic
    Abstract:

    Geometry and magnetic relaxation modulations in a series of mononuclear Dysprosium complexes, [DyLz2(o-vanilin)2]·X·solvent (Lz = 6-pyridin-2-yl-[1,3,5]triazine-2,4-diamine; X = Br− (1), NO3− (2), CF3SO3− (3)), were realized by changing the nature of the counter-anion. The DyIII ions in all complexes are eight-coordinate and in approximate D4d symmetry environments. The magnetic relaxation and anisotropy of these complexes were systematically investigated, both experimentally and from ab initio calculations. All complexes exhibit excellent single-molecule magnetic behavior. Remarkably, magneto-structural studies show that the rotation of the coordinating plane of the square-antiprismatic environment in complex 2 induces a magnetic relaxation path through higher excited states, yielding a high anisotropy barrier of 615 K (696 K for a diluted sample). Additionally, obvious opening of the hysteresis loop is observed up to 7 K, which is the highest blocking temperature ever reported for Dysprosium single-molecule magnets.

  • tuning the magnetic interactions and relaxation dynamics of dy2 single molecule magnets
    Chemistry: A European Journal, 2015
    Co-Authors: Liviu Ungur, Jinkui Tang, Liviu F Chibotaru
    Abstract:

    Efficient modulation of single-molecule magnet (SMM) behavior was realized by deliberate structural modification of the Dy-2 cores of [Dy-2(a'povh)(2)(OAc)(2)(DMF)(2)] (1) and [Zn2Dy2(a'povh)(2)(OAc)(6)]center dot 4H(2)O (2; H(2)a'povh=N'-[amino(pyrimidin-2-yl)methylene]-o-vanilloyl hydrazine). Compound 1 having fourfold linkage between the two Dysprosium ions shows high-performance SMM behavior with a thermal energy barrier of 322.1 K, whereas only slow relaxation is observed for compound 2 with only twofold connection between the Dysprosium ions. This remarkable discrepancy is mainly because of strong axiality in 1 due to one pronounced covalent bond, as revealed by experimental and theoretical investigations. The significant antiferromagnetic interaction derived from bis(mu(2)-O) and two acetate bridging groups was found to be crucial in leading to a nonmagnetic ground state in 1, by suppressing zero-field quantum tunneling of magnetization.

  • an asymmetrically connected hexanuclear dyiii6 cluster exhibiting slow magnetic relaxation
    Inorganic Chemistry Communications, 2013
    Co-Authors: Soumya Mukherjee, Jinkui Tang, Abhijeet K Chaudhari, Sujit K Ghosh
    Abstract:

    A new hexanuclear Dysprosium(III) cluster [Dy-6(L)(7)(HL)(MeOH)(2)(H2O)(OH)(2)(OAc)] (1) has been synthesized from the schiff base ligand o-phenolsalicylimine and Dysprosium nitrate. This unique Dy(III)6 cluster, constituted of an exclusive combination of two vertex-sharing and one edge-sharing high-anisotropy Dy-3 triangles assembled together forming an unprecedentedly asymmetric homometallic Dy(III)6 core, shows slow relaxation of the magnetization. (C) 2013 Elsevier B.V. All rights reserved.

  • quadruple co32 bridged octanuclear Dysprosium iii compound showing single molecule magnet behaviour
    Chemical Communications, 2012
    Co-Authors: Jinkui Tang, Lang Zhao, Haiquan Tian, Yunnan Guo, Yang Guo, Zhiliang Liu
    Abstract:

    A novel octanuclear Dysprosium(III) compound, templated by quadruple μ4-CO32− introduced via spontaneous fixation of atmospheric carbon dioxide, shows single-molecule-magnet behaviour with an obvious hysteresis loop detected by a traditional SQUID magnetometer.

  • relaxation dynamics of Dysprosium iii single molecule magnets
    ChemInform, 2011
    Co-Authors: Yunnan Guo, Yang Guo, Jinkui Tang
    Abstract:

    Over the past decade, lanthanide compounds have become of increasing interest in the field of Single Molecule Magnets (SMMs) due to the large inherent anisotropy of the metal ions. Heavy lanthanide metal systems, in particular those containing the Dysprosium(III) ion, have been extensively employed to direct the formation of a series of SMMs. Although remarkable progress is being made regarding the synthesis and characterization of lanthanide-based SMMs, the understanding and control of the relaxation dynamics of strongly anisotropic systems represents a formidable challenge, since the dynamic behaviour of lanthanide-based SMMs is significantly more complex than that of transition metal systems. This perspective paper describes illustrative examples of pure Dysprosium(III)-based SMMs, published during the past three years, showing new and fascinating phenomena in terms of magnetic relaxation, aiming at shedding light on the features relevant to modulating relaxation dynamics of polynuclear lanthanide SMMs.

Richard E P Winpenny - One of the best experts on this subject based on the ideXlab platform.

  • the first near linear bis amide f block complex a blueprint for a high temperature single molecule magnet
    Chemical Communications, 2015
    Co-Authors: Nicholas F Chilton, Conrad A P Goodwin, David P Mills, Richard E P Winpenny
    Abstract:

    We report the first near-linear bis(amide) 4f-block compound and show that this novel structure, if implemented with Dysprosium(III), would have unprecedented single molecule magnet (SMM) properties with an energy barrier, Ueff, for reorientation of magnetization of 1800 cm−1.

  • an electrostatic model for the determination of magnetic anisotropy in Dysprosium complexes
    Nature Communications, 2013
    Co-Authors: Nicholas F Chilton, David Collison, Eric J L Mcinnes, Richard E P Winpenny, Alessandro Soncini
    Abstract:

    Understanding the anisotropic electronic structure of lanthanide complexes is important in areas as diverse as magnetic resonance imaging, luminescent cell labelling and quantum computing. Here we present an intuitive strategy based on a simple electrostatic method, capable of predicting the magnetic anisotropy of Dysprosium(III) complexes, even in low symmetry. The strategy relies only on knowing the X-ray structure of the complex and the well-established observation that, in the absence of high symmetry, the ground state of Dysprosium(III) is a doublet quantized along the anisotropy axis with an angular momentum quantum number mJ=±(15)/2. The magnetic anisotropy axis of 14 low-symmetry monometallic Dysprosium(III) complexes computed via high-level ab initio calculations are very well reproduced by our electrostatic model. Furthermore, we show that the magnetic anisotropy is equally well predicted in a selection of low-symmetry polymetallic complexes.

  • magnetic relaxation pathways in lanthanide single molecule magnets
    Nature Chemistry, 2013
    Co-Authors: Robin J Blagg, Liviu Ungur, James Speak, Priyanka Comar, Liviu F Chibotaru, David Collison, Wolfgang Wernsdorfer, Floriana Tuna, Eric J L Mcinnes, Richard E P Winpenny
    Abstract:

    Dysprosium alkoxides and Dysprosium-doped yttrium alkoxides show very large energy barriers, greater than 800 K, to magnetic relaxation. These barriers arise from the presence of a strongly axial pseudo-octahedral crystal field, which switches off relaxation through the first excited state that typically occurs in single-molecule magnets, and favours a competitive pathway through higher-energy states.

  • single pyramid magnets dy5 pyramids with slow magnetic relaxation to 40 k
    Angewandte Chemie, 2011
    Co-Authors: Robin J Blagg, Floriana Tuna, Eric J L Mcinnes, Christopher A Muryn, Richard E P Winpenny
    Abstract:

    Single-molecule magnets: A square-pyramidal pentametallic Dysprosium cluster was synthesized and showed slow magnetic relaxation at temperatures as high as 40 K. The thermal energy barrier to relaxation of magnetization of this single-molecule magnet was found at a temperature of 530 K and is the largest yet observed for any d- or f-block cluster compound.

  • influence of the n bridging ligand on magnetic relaxation in an organometallic Dysprosium single molecule magnet
    Chemistry: A European Journal, 2010
    Co-Authors: Richard A Layfield, David Collison, Floriana Tuna, Joseph J W Mcdouall, Scott A Sulway, Richard E P Winpenny
    Abstract:

    Organometallic single-molecule magnet: Studies of two dimeric organometallic Dysprosium compounds reveal one to be the first organometallic single-molecule magnet (see picture). A comparison of the magnetic properties and electronic structures of the two compounds shows that Dy⋅⋅⋅Dy interactions have a profound influence on the dynamic magnetic behaviour, while having little effect on the static magnetic measurements.

Liviu Ungur - One of the best experts on this subject based on the ideXlab platform.

  • tuning the magnetic interactions and relaxation dynamics of dy2 single molecule magnets
    Chemistry: A European Journal, 2015
    Co-Authors: Liviu Ungur, Jinkui Tang, Liviu F Chibotaru
    Abstract:

    Efficient modulation of single-molecule magnet (SMM) behavior was realized by deliberate structural modification of the Dy-2 cores of [Dy-2(a'povh)(2)(OAc)(2)(DMF)(2)] (1) and [Zn2Dy2(a'povh)(2)(OAc)(6)]center dot 4H(2)O (2; H(2)a'povh=N'-[amino(pyrimidin-2-yl)methylene]-o-vanilloyl hydrazine). Compound 1 having fourfold linkage between the two Dysprosium ions shows high-performance SMM behavior with a thermal energy barrier of 322.1 K, whereas only slow relaxation is observed for compound 2 with only twofold connection between the Dysprosium ions. This remarkable discrepancy is mainly because of strong axiality in 1 due to one pronounced covalent bond, as revealed by experimental and theoretical investigations. The significant antiferromagnetic interaction derived from bis(mu(2)-O) and two acetate bridging groups was found to be crucial in leading to a nonmagnetic ground state in 1, by suppressing zero-field quantum tunneling of magnetization.

  • influencing the properties of Dysprosium single molecule magnets with phosphorus donor ligands
    Nature Communications, 2015
    Co-Authors: Thomas Pugh, Liviu Ungur, Liviu F Chibotaru, David Collison, Floriana Tuna, Eric J L Mcinnes, Richard A Layfield
    Abstract:

    Ligand design contributes to dictating the magnetic properties of lanthanide-based single-molecule magnets. Here, the authors report a series of phosphorus-ligated Dysprosium complexes, and show that the dynamic magnetic properties change as the ligand is varied from phosphine to phosphide to phosphinidene.

  • chemical tuning of the magnetic relaxation in Dysprosium iii mononuclear complexes
    Dalton Transactions, 2014
    Co-Authors: Luke J Batchelor, Liviu Ungur, Liviu F Chibotaru, Wolfgang Wernsdorfer, Floriana Tuna, Irene Cimatti, Regis Guillot, Victoria E Campbell, Talal Mallah
    Abstract:

    A Dysprosium(III) complex, exhibiting slow relaxation of magnetization, was prepared. Crystallographic studies showed a perturbation of local symmetry upon deprotonation of the ligand, with concomitant faster relaxation of magnetization. This was attributed to a large shift in the direction of the main magnetic axis, as indicated by ab initio calculations.

  • magnetic relaxation pathways in lanthanide single molecule magnets
    Nature Chemistry, 2013
    Co-Authors: Robin J Blagg, Liviu Ungur, James Speak, Priyanka Comar, Liviu F Chibotaru, David Collison, Wolfgang Wernsdorfer, Floriana Tuna, Eric J L Mcinnes, Richard E P Winpenny
    Abstract:

    Dysprosium alkoxides and Dysprosium-doped yttrium alkoxides show very large energy barriers, greater than 800 K, to magnetic relaxation. These barriers arise from the presence of a strongly axial pseudo-octahedral crystal field, which switches off relaxation through the first excited state that typically occurs in single-molecule magnets, and favours a competitive pathway through higher-energy states.

  • the first dy4 single molecule magnet with a toroidal magnetic moment in the ground state
    Inorganic Chemistry, 2012
    Co-Authors: Penghu Guo, Liviu Ungur, Liviu F Chibotaru, Junliang Liu, Zemin Zhang, Jidong Leng, Fusheng Guo, Mingliang Tong
    Abstract:

    A toroidal magnetic moment in the absence of a conventional total magnetic moment was first observed in a novel tetranuclear Dysprosium cluster with nonmagnetic ground state. The toroidal state is quite robust with respect to variations of the exchange parameters.

C A Ross - One of the best experts on this subject based on the ideXlab platform.

  • Dysprosium substituted ce yig thin films with perpendicular magnetic anisotropy for silicon integrated optical isolator applications
    APL Materials, 2019
    Co-Authors: Chuangtang Wang, Wei Yan, Longjiang Deng, C A Ross
    Abstract:

    In this report, Dysprosium substituted Ce1Y2Fe5O12 (Ce:YIG) thin films (Dy:CeYIG) with perpendicular magnetic anisotropy (PMA) are successfully deposited on silicon and silicon-on-insulator waveguides by pulsed laser deposition. The structural, magnetic, and magneto-optical properties of Dy:CeYIG films are investigated. We find that increasing Dysprosium concentration leads to a decreased out-of-plane magnetic saturation field. Dy2Ce1Fe5O12 and Dy2Ce1Al0.4Fe4.6O12 thin films show PMA dominated by magnetoelastic effects due to thermal mismatch strain. These films further exhibit high Faraday rotation and low optical loss. Our work demonstrates that Dy substitution is an effective way to induce PMA in Ce:YIG thin films without compromising their magneto-optical figure of merit, making this material promising for self-biased transverse electric mode optical isolator applications.In this report, Dysprosium substituted Ce1Y2Fe5O12 (Ce:YIG) thin films (Dy:CeYIG) with perpendicular magnetic anisotropy (PMA) are successfully deposited on silicon and silicon-on-insulator waveguides by pulsed laser deposition. The structural, magnetic, and magneto-optical properties of Dy:CeYIG films are investigated. We find that increasing Dysprosium concentration leads to a decreased out-of-plane magnetic saturation field. Dy2Ce1Fe5O12 and Dy2Ce1Al0.4Fe4.6O12 thin films show PMA dominated by magnetoelastic effects due to thermal mismatch strain. These films further exhibit high Faraday rotation and low optical loss. Our work demonstrates that Dy substitution is an effective way to induce PMA in Ce:YIG thin films without compromising their magneto-optical figure of merit, making this material promising for self-biased transverse electric mode optical isolator applications.

  • Dysprosium substituted ce yig thin films with perpendicular magnetic anisotropy for silicon integrated optical isolator applications
    APL Materials, 2019
    Co-Authors: Yan Zhang, Chuangtang Wang, Wei Yan, Longjiang Deng, C A Ross
    Abstract:

    In this report, Dysprosium substituted Ce1Y2Fe5O12 (Ce:YIG) thin films (Dy:CeYIG) with perpendicular magnetic anisotropy (PMA) are successfully deposited on silicon and silicon-on-insulator waveguides by pulsed laser deposition. The structural, magnetic, and magneto-optical properties of Dy:CeYIG films are investigated. We find that increasing Dysprosium concentration leads to a decreased out-of-plane magnetic saturation field. Dy2Ce1Fe5O12 and Dy2Ce1Al0.4Fe4.6O12 thin films show PMA dominated by magnetoelastic effects due to thermal mismatch strain. These films further exhibit high Faraday rotation and low optical loss. Our work demonstrates that Dy substitution is an effective way to induce PMA in Ce:YIG thin films without compromising their magneto-optical figure of merit, making this material promising for self-biased transverse electric mode optical isolator applications.