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Magnetic Order (magnetic + order)
Selected AbstractsChemInform Abstract: Jahn,Teller Distorted Frameworks and Magnetic Order in the Rb,Mn,P,O System.CHEMINFORM, Issue 23 2010Fiona C. Coomer Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Three-Dimensional Lanthanoid-Containing Coordination Frameworks: Structure, Magnetic and Fluorescent PropertiesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2005Hong-Tao Zhang Abstract Two lanthanoid-containing 3D coordination polymers, [Gd2L3(H2O)2]n (1) and {[TbL1.5(H2O)]·0.5H2O}n (2) (L = succinate), have been prepared by hydrothermal reaction. The difference in structure between the two 3D coordination polymers is a result of the flexibility of the ligand conformation. The magnetic properties of 1 and 2 have been investigated in the 1.8,300 K range. Both complexes exhibit ferromagnetic interaction between lanthanoid ions. AC magnetic measurements revealed long-range magnetic order in complex 2. Especially 2 integrates the ferromagnetic, fluorescent and porous properties into a single entity. This motif may be developed to achieve new multifunctional molecular-based materials. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] New Molecular Charge-Transfer Salts of TM-TTF and BMDT-TTF with Thiocyanate and Selenocyanate Complex Anions [TMTTF = Tetramethyltetrathiafulvalene; BMDT-TTF = Bis(methylenedithio)tetrathiafulvalene]EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2003Marta Mas-Torrent Abstract Three new charge-transfer salts of tetrathiafulvalene (TTF)-based donors with thiocyanato- or selenocyanato-metal complex anions have been synthesised. The salts isolated were [BMDT-TTF]4[Cr(NCS)6] (1), [TM-TTF]4[Cr(NCS)6]·2CH3CN (2) and [TM-TTF]4[Cr(NCSe)6]·2CH3CN (3) [BMDT-TTF = bis(methylenedithio)tetrathiafulvalene and TM-TTF = tetramethyltetrathiafulvalene]. Single crystals of compound 1 crystallise in the monoclinic C2/c space group with a = 37.286(3), b = 10.0539(6), c = 21.069(2) Å, , = 124.348(4)°, V = 6520.9(9) Å3 and Z = 4. Compound 3 was also suitable for an X-ray diffraction study, however the anionic part, [Cr(NCSe)6], was highly disordered and the best solution gave a final R factor of 16.4%. A solution was found for the monoclinic space group C2/m with a = 13.787(3), b = 19.507(3), c = 14.735(5) Å, , = 102.90(3)°, V = 3862.9(17) Å3 and Z = 2. For compound 1 there are several S···S close atomic contacts between the donors and acceptors, but there is no discernible magnetic exchange between ions. Such an interaction was previously observed in related salts such as [TTF][Cr(NCS)4(phenanthroline)2] and [donor][M(NCS)4(isoquinoline)2] [M = Cr, Fe and donor = TTF, BEDT-TTF or TM-TTF (tetramethyltetrathiafulvalene)]. Compounds 1 to 3 are all paramagnetic semiconductors in which the magnetic susceptibility is dominated by the Cr-containing anions. The structure-function relationship, along with a comparison with related compounds, indicates that there is no long-range magnetic order because there are no ,-stacking interactions between donor and acceptor; these types of interactions are seen in all of the bulk magnets of this type in which the donor spin is magnetically coupled to the anion. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Magnetic and dielectric properties of the ruthenium double perovskites La2MRuO6 (M = Mg, Co, Ni, and Zn)PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2006Kenji Yoshii Abstract Magnetic and dielectric properties of the ruthenium double perovskites La2MRuO6 (M = Mg, Co, Ni, and Zn) were investigated. The magnetization measurements for M = Co and Ni showed the existence of magnetic order at 20,30 K. Though the oxides with M = Zn and Mg exhibit a deviation from the Curie,Weiss law, magnetic order was not clearly observed. The result of La2ZnRuO6 was different from that previously reported, in which a ferromagnetic transition was found at around 165 K. The AC dielectric measurements for M = Co and Ni showed large dielectric constants (typically larger than 1000) at around room temperature, suggesting both the formation of short-ranged polar regions and the magnetic origin of large dielectric constant. In addition, two peaks were found for the temperature dependence of the tan , component for La2NiRuO6. The behavior suggests the existence of two different polar regions. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Influence of the Mn compositional distribution on the magnetic order in diluted GaMnN layersPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008D. Mai Abstract GaMnN is a prototypical GaN-based dilute magnetic semiconductor (DMS) and its potential as a room temperature ferromagnetic material is still a controversial question to be answered. Diluted GaMnN layers with Mn concentrations up to several percent have been grown by plasma-assisted MBE on MOVPE-GaN templates either on p-Si(111) or on Al2O3(0001) substrates. None of the samples reported here shows second phase precipitates in XRD or in the TEM analysis. However different composition distributions have been evidenced by EDX during the scanning TEM analysis. GaMnN grown at a substrate temperature of TS = 650 °C exhibits extended structural defects and strong compositional inhomogeneity. This could be indicative of decomposition due to local strain. Samples grown at TS = 775 °C with a Mn concentration of about 3% show a homogeneous Mn distribution in the layer. The magnetic properties are found to vary from spin glass to ferromagnetic behaviour at room temperature among different samples. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Quasi-particle peak due to magnetic order in strongly correlated electron systemsANNALEN DER PHYSIK, Issue 8 2010T.A. Zaleski Abstract We study the electron spectral function of the antiferromagnetically ordered phase of the three dimensional Hubbard model, using recently formulated low-energy theory based on the 2D half-filled Hubbard model which describes both collective spin and charge fluctuations for arbitrary value of the Coulomb repulsion U. The model then is solved by a saddle-point approximation within the CP1 representation for the Neel field. The single-particle properties are obtained by writing the fermion field in terms of a U(1) phase, Schwinger boson SU(2) fields and a pseudofermion variables. We demonstrate that the appearance of a sharp peak in the electron spectral function in the antiferromagnetic state points to the emergence of the bosonic mode, which is associated with spin ordering. [source] | |||||||||||||