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Magnetic Characterization (magnetic + characterization)

Distribution by Scientific Domains

Chemistry	57%
Physics and Astronomy	42%

Selected Abstracts

Synthesis, Structural, Thermal and Magnetic Characterization of a Pyrophosphato-Bridged Cobalt(II) Complex

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2008
Oluwatayo F. Ikotun
Abstract The reaction in water of CoII sulfate heptahydrate with 1,10-phenanthroline (phen) and sodium pyrophosphate (Na4P2O7) in a 2:4:1 stoichiometric ratio resulted in the crystallization of a neutral dinuclear CoII complex, {[Co(phen)2]2(,-P2O7)}·6MeOH (1), as revealed by a single-crystal X-ray diffraction study. The bridging pyrophosphato ligand between the two [Co(phen)2]2+ units in a bis(bidentate) coordination mode places the adjacent metal centers at 4.857 Å distance, and its conformation gives rise to intramolecular ,,, stacking interaction between adjacent phen ligands. Indeed, intermolecular ,,, stacking interactions between phen ligands from adjacent dinuclear complexes create a supramolecular 2D network in 1. Magnetic susceptibility measurements on a polycrystalline sample of 1 in the temperature range 1.9,295 K are typical of an overall antiferromagnetic coupling with a maximum of the magnetic susceptibility at 3.0 K. The analysis of the magnetic data in the whole temperature range allows the determination of the value of the intramolecular magnetic coupling (J = ,1.23 cm,1). The ability of the pyrophosphato ligand to mediate magnetic interactions between different first-row transition-metal ions when adopting the bis(bidentate) bridging mode is analyzed and discussed in the light of the small number of magneto-structural reports on this type of compound, bearing in mind the number of unpaired electrons and type of magnetic orbitals on each metal center. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source]

Synthesis, Structural, and Magnetic Characterization of YCrMnO5

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2005
José A. Alonso
Abstract A new oxide of nominal stoichiometry YCrMnO5 has been prepared in polycrystalline form by wet-chemistry procedures followed by thermal treatments under high-oxygen-pressure conditions. This material has been characterized by X-ray and neutron powder diffraction (NPD), magnetotransport and magnetization measurements. YCrMnO5 is isostructural with RMn2O5 oxides (R = rare earths); its crystal structure has been Rietveld refined from NPD data in the space group Pbam, and it contains infinite chains of(Cr,Mn)4+O6 octahedra sharing edges, linked together by (Mn,Cr)3+O5 pyramids and YO8 units. An important level of cationic disorder has been found between both metallic sites; the refined crystallographic formula is Y[Mn0.47(1)Cr0.53(1)]oct[Cr0.37(1)Mn0.63(1)]pyrO5. The magnetic susceptibility indicates the onset of magnetic ordering below Tc , 85 K; the magnetization isotherms are characteristic of a weakly ferrimagnetic material reaching a net magnetization of0.25 ,B/f.u. for H = 50 kOe. Low-temperature NPD patterns do not exhibit any additional magnetic contribution, confirming that a long-range magnetic ordering is not fully established. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

ChemInform Abstract: Preparation, Structural and Magnetic Characterization of DyCrMnO5.

CHEMINFORM, Issue 25 2009
M. J. Martinez-Lope
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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]

Synthesis, Structural, and Magnetic Characterization of a New Ferrimagnetic Oxide: YFeMnO5.

CHEMINFORM, Issue 51 2004
A. Munoz
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Magnetic characterization of Cretaceous-Tertiary boundary sediments

METEORITICS & PLANETARY SCIENCE, Issue 9 2007
Víctor Villasante-Marcos
Studied sections' locations vary in distance to the Chicxulub structure from distal (Agost and Caravaca, Spain), through closer (ODP Hole 1049A, Blake Nose, North Atlantic), to proximal (El Mimbral and La Lajilla, Mexico). A clear magnetic signature is associated with the fireball layer in the most distal sections, consisting of a sharp increase in susceptibility and saturation isothermal remanent magnetization (SIRM), and a decrease in remanence coercivity. Magnetic properties in these sections point to a distinctive ferrimagnetic phase, probably corresponding to the reported Mg- and Ni-rich, highly oxidized spinels of meteoritic origin. At closer and proximal sections magnetic properties are different. Although there is an increase in susceptibility and SIRM associated with a rusty layer placed on top of the siliciclastic deposit in proximal sections, and with a similar limonitic layer on top of the spherule bed that defines the boundary at Blake Nose, the magnetic properties indicate a mixture of iron oxyhydroxides dominated by fine-grained goethite. Based on previous geochemical studies at Blake Nose and new geochemical and PGE abundance measurements performed in this work at El Mimbral, this goethite-rich layer can be interpreted as an effect of diagenetic remobilization and precipitation of Fe. There is not enough evidence to assert that this Fe concentration layer at proximal sections is directly related to deposition of fine meteoritic material. Magnetic, geochemical, and iridium data reject it as a primary meteoritic phase. [source]

Magnetic characterization of U/Co multilayers

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
M. A. Rosa
Abstract With the aim of expanding the studies on 2D systems containing uranium, U/Co multilayers with layer thickness ranging from 50 to 200 Å were recently prepared by dc magnetron sputtering onto glass. The multilayers were characterized by Grazing-Incidence X-Ray Diffraction (GIXRD) and Rutherford Backscattering Spectrometry (RBS). Magnetization measurements performed with a squid magnetometer showed that the multilayers have a ferromagnetic behaviour, with the magnetic signal increasing with the thickness of the layers. The analysis of magnetic anisotropy evidenced an easy magnetic direction in the film plane with large anisotropy fields, which increase with the thickness of the layers and suggests a positive contribution of surface anisotropy to the effective anisotropy Keff. [source]

Magnetic and electrical properties of BiMnO3 thin films

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 11 2007
M. Grizalez
Abstract BiMnO3 thin films were deposited on single-crystal (001)-oriented SrTiO3 substrates by rf-magnetron sputtering method. X-ray diffraction was used to analyze the crystal structure of the thin films, indicating that the films were monoclinic with two dominant orientation relationships along the substrate. The first is (111) BiMnO3 , (001) SrTiO3; the second is (222) BiMnO3 , (002) SrTiO3; other peaks showed that the films were polycrystalline. The roughness of the films was characterized by AFM. R vs. T was measured from 390 K to 15 K using a Keithley Model 167 Programmable Electrometer. Magnetic characterization was carried out by using a quantum designÔ magnetometer for magnetization versus temperature and for hysteresis loops at different temperatures. The saturation magnetic moment of 2.8,B per Mn ion (still fairly smaller than that of the bulk, 3.6,B) was observed at 5 K decreasing with increasing temperature. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]