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Ferromagnetic Exchange (ferromagnetic + exchange)

Distribution by Scientific Domains
Chemistry60%
Physics and Astronomy40%

Terms modified by Ferromagnetic Exchange

  • ferromagnetic exchange interaction
    		•

    Selected Abstracts

    Ferrocene-Substituted [Mn4] Dicubane Single-Molecule Magnets

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 24 2009
    Katie J. Heroux
    Abstract Two new mixed-valent [Mn4] single-molecule magnets (SMMs) have been synthesized by using N -alkylated diethanolamine ligands and ferrocenecarboxylic acid. Both complexes exhibit weak ferromagnetic exchange and appreciable axial zero-field splitting as evidenced by DC magnetic susceptibility and field-dependent magnetization measurements. A significant frequency-dependent out-of-phase signal in the AC susceptibility is also observed for both complexes, a feature that is characteristic of SMMs. The ground-state spin of each complex was determined from the DC data and extrapolation of the low-frequency AC data, giving a value of S = 8. This result is consistent with the previously reported and structurally similar S = 8 and S = 9 [Mn4] dicubane SMMs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

    Dinuclear Complexes of MII Thiocyanate (M = Ni and Cu) Containing a Tridentate Schiff-Base Ligand: Synthesis, Structural Diversity and Magnetic Properties

    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2005
    Suparna Banerjee
    Abstract A dinuclear NiII complex, [Ni2(L)2(H2O)(NCS)2]·3H2O (1) in which the metal atoms are bridged by one water molecule and two ,2 -phenolate ions, and a thiocyanato-bridged dimeric CuII complex, [Cu(L)NCS]2 (2) [L = tridentate Schiff-base ligand, N -(3-aminopropyl)salicylaldimine, derived from 1:1 condensation of salicylaldehyde and 1,3-diaminopropane], have been synthesized and characterized by IR and UV/Vis spectroscopy, cyclic voltammetry and single-crystal X-ray diffraction studies. The structure of 1 consists of dinuclear units with crystallographic C2 symmetry in which each NiII atom is in a distorted octahedral environment. The Ni,O distance and the Ni,O,Ni angle, through the bridged water molecule, are 2.240(11) Å and 82.5(5)°, respectively. The structure of 2 consists of dinuclear units bridged asymmetrically by di-,1,3 -NCS ions; each CuII ion is in a square-pyramidal environment with , = 0.25. Variable-temperature magnetic susceptibility studies indicate the presence of dominant ferromagnetic exchange coupling in complex 1 with J = 3.1 cm,1, whereas complex 2 exhibits weak antiferromagnetic coupling between the CuII centers with J = ,1.7 cm,1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

    New tin(IV) complexes with sterically hindered o -iminobenzoquinone ligand: Synthesis and structure

    HETEROATOM CHEMISTRY, Issue 6 2009
    Alexandr V. Piskunov
    The reduction of 4,6-di-tert-butyl-N-(2, 6-di-iso-propylphenyl)-o-iminobenzoquinone (imQ) by tin amalgam in hexane solution leads to new six-coordinated o-iminoquinonato tin(IV) complex (iSQ)2SnAP (1) (where iSQ and AP are o-iminosemiquinolate and dianion o-amidophenolate, respectively). Variable temperature magnetic susceptibility measurements of 1 have shown that this complex possesses a weak ferromagnetic exchange between o-iminosemiquinonate ligands. The oxidation of 1 with air oxygen produces new o-iminoquinonolate tin(IV) derivatives [(iSQ)Sn(AP)]2O (2) and (iSQ)2Sn(OH)2 (3) containing ,-oxo- and hydroxo-ligands, respectively. The electronic structure of 1 was examined by DFT analysis. Complexes 1,3 have been investigated using single-crystal X-ray diffraction. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:332,340, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20555 [source]

    Ferromagnetism in epitaxial Zn0.95Co0.05O films grown on ZnO and Al2O3

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 14 2006
    K. Nielsen
    Abstract In this article, the possible mechanisms resulting in strong ferromagnetic coupling in transition metal(TM)-doped ZnO and other diluted magnetic semiconductors (DMS) are reviewed and the prerequisites for the observation of room temperature ferromagnetism in TM-doped ZnO are defined. In order to study the ferromagnetic behavior we have grown epitaxial Zn0.95Co0.05O films simultaneously on (0001) ZnO and Al2O3 substrates by laser molecular beam epitaxy at different deposition temperatures. A systematic study of the structural and magnetic properties has been performed to reveal their interdependence. Room temperature ferromagnetism has been found in Zn0.95Co0.05O films grown on ZnO, whereas for films deposited on sapphire only weak ferromagnetic signals have been detected which could not unambiguously be separated from those of the substrate. The different behavior is explained by different structural properties and defect densities in both films. Our experimental findings are in good agreement with a spin split impurity band model, where strong ferromagnetic exchange in ZnO:Co2+ is obtained by a strong hybridization between the magnetic Co2+ ion states and the donor states due to a large density of native defects. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Antiferromagnetic-to-ferromagnetic transition induced by aluminum in the Ti(Fe1,xAlx)2 intermetallic compounds: a 57Fe Mössbauer spectroscopy study

    PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2007
    N. N. Delyagin
    Abstract Mössbauer spectroscopy has been used to investigate the hyperfine field distributions and the local spin configurations of Fe atoms in the magnetically ordered Ti(Fe1,xAlx)2 compounds. The evolution of the spin arrangement of the Fe atoms was observed over the concentration range 0 , x , 0.25 at 5 K. The Al impurity suppresses the ferromagnetic exchange in the Fe(6h) layers and simultaneously provides the conditions for a transition of the Fe(2a) atoms, which are nonmagnetic in the TiFe2 compound, to the states with nonzero magnetic moment. The magnetic behavior of the Fe(2a) atoms is the key factor governing the anti- to ferromagnetic transition in the Ti(Fe1,xAlx)2 compounds. The magnetic ordering temperatures of the Ti(Fe1,xAlx)2 compounds were determined. In addition, the parameters of the electric-field gradient in TiFe2 as well as the relationship between the value of the magnetic moment of the Fe atom and the type of atomic configuration were discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]