Search results for "Susceptibility"

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co3Mo3C

2010

We report the magnetic properties of the cobalt molybdenum η-carbide-type compounds Co 3 Mo 3 C and Co 3 Mo 3 N. The magnetic susceptibility χ of Co 3 Mo 3 C shows a Curie–Weiss temperature dependence at high temperatures and a broad maximum at around 100 K, whereas that of Co 3 Mo 3 N shows a nearly temperature-independent enhanced Pauli paramagnetic behavior. The absence of a magnetic long-range order was confirmed by the nuclear magnetic resonance technique in both the compounds. As expected from the broad maximum of χ, we observed an itinerant electron metamagnetic transition at around 37 T in Co 3 Mo 3 C.

Synthesis, crystal structure and magnetic properties of a new cyanide-bridged mixed-valence copper(I)/copper(II) clathrate

2013

A unique cyanide-bridge mixed-valence CuI/CuII clathrate of formula [CuI2(CN)3][{CuII(tren)}2(μ-CN)](CF3SO3)2 [tren = tris(2-aminoethyl)amine] containing cyanide-bridged [{CuII(tren)}2(μ-CN)]3 + binuclear cations stacked between anionic honeycomb layered copper(I) cyanide networks, was synthesized and structurally characterized by single crystal X-ray diffraction. Variable-temperature magnetic susceptibility studies showed that the cyanide bridge mediates a strong antiferromagnetic interaction between the copper(II) centers (J = − 160 cm− 1, the spin Hamiltonian being defined as H = − JSA⋅SB).

Spin-Crossover and Liquid Crystal Properties in 2D Cyanide-Bridged FeII−MI/II Metalorganic Frameworks

2010

Novel two-dimensional heterometallic Fe(II)-M(Ni(II), Pd(II), Pt(II), Ag(I), and Au(I)) cyanide-bridged metalorganic frameworks exhibiting spin-crossover and liquid crystal properties, formulated as {FeL(2)[M(I/II)(CN)(x)](y)}·sH(2)O, where L are the ligands 4-(4-alkoxyphenyl)pyridine, 4-(3,4-dialkoxyphenyl)pyridine, and 4-(3,4,5-trisalkoxyphenyl)pyridine, have been synthesized and characterized. The physical characterization has been carried out by means of EXAFS, X-ray powder diffraction, magnetic susceptibility, differential scanning measurements, and Mössbauer spectroscopy. The 2D Fe(II) metallomesogens undergo incomplete and continuous thermally induced spin transition at T(1/2) ≈ 170 …

Iron(II) metallomesogens based on symmetrical tripod ligands

2012

Abstract Novel mononuclear tripodand-based iron(II) complexes showing liquid crystal properties have been synthesized and characterized. These are based on ligands tris[3-aza-4-((5-Cn)(6-R-2-pyridyl))but-3-enyl]amine, where R = hydrogen or methyl, 1,3,5-cis,cis-tris[1-aza-2-((5-alkyloxy)(2-pyridyl))vinyl]cyclohexane and 2,2,2-tris(2-aza-3-((5-alkyloxy)(2-pyridyl))prop-2-enyl)ethane. The physical characterization has been carried out by means of single-crystal X-ray diffraction measurements, magnetic susceptibility, differential scanning calorimetry, X-ray powder diffraction and Mossbauer spectroscopy.

Astronomical calibration of the Valanginian and the Hauterivian stages (lower cretaceous) : paleoclimatic and paleooceanographic implications

2013

Orbital floating time scales are proposed for the Valanginian Stage and part of the Hauterivian Stage (Early Cretaceous). These are based on the identification of the eccentricity cycles from spectral analyses performed on high-resolution climatic proxies measured on hemipelagic marl-limestone alternations. Five reference sections were analysed in the Vocontian Basin (SE France), spanning the entire Valanginian. A duration of 5,08 myr is proposed for the Valanginian Stage from the identification of the 405-kyr eccentricity cycle. The time frame proposed, combined with available radiometric ages, shows that the mid-Valanginian 13C positive excursion (namely the Weissert Event) occurs prior …

A Comparison between Heuristic, Statistical and Data-driven Methods in Landslide Susceptibility Assessment: an Application to the Briga and Giampilie…

2014

Susceptibility assessment concerning the estimation of areas prone to landslide is one of the most useful approach in the analysis of landslide hazard. Over the last years, in an attempt to find the best approach to evaluate landslide susceptibility, many methods have been developed. Among these, the heuristic, the statistical, and the data-driven approaches are very widespread, and they all are based on the concept that the conditions which led to landslide movements in the past will control the probability of movement occurrence in the future. This study presents an assessment of landslide susceptibility in which models of the three different methodologies, such as the heuristic approach,…

Regional debris flow susceptibility assessment using HRDEM: Example of the city area of Messina (Sicily, Italy)

2014

Shallow landslide and debris flows are among the most dangerous natural hazards triggered by extreme meteorological events. These phenomena have recently caused catastrophic scenarios in Italy (e.g. in Sarno-Quindici and Giampilieri) and, according to expected changes in the climate pattern, an increasing frequency of these phenomena is expected. The aim of this research is to assess the debris flow susceptibility in the Giampilieri area (Sicily) using a spatially-distributed debris flow runout model based on topographic information. The application of the model starts with the identification of the source areas from which debris flows are propagated on the basis of frictional laws and flow…

Comparing binary logistic regression and stochastic gradient boosting techniques in debris-flows susceptibility modelling: application in North-Easte…

2013

Self-assembly, binding ability and magnetic properties of dicopper(ii) pyrazolenophanes

2016

A novel series of dinuclear copper(II) pyrazolenophanes of the formula [Cu2(μ-4-Mepz)2(μ-ClO4)(ClO4)(bpm)2] (1), [Cu2(μ-pz)2(μ-H2O)(ClO4)(4,7-Me2phen)2]ClO4·H2O·CH3CN (2), [Cu2(μ-pz)2(μ-H2O)(ClO4)3/2(H2O)1/2(phen)2]2[Cu2(μ-pz)2(μ-ClO4)(ClO4)2(phen)2]·8H2O (3), and [Cu2(μ-pz)2(CH3CN)2(3,4,7,8-Me4phen)2](ClO4)2 (4) (Hpz = pyrazole, H-4-Mepz = 4-methylpyrazole, bpm = 2,2'-bipyrimidine, phen = 1,10-phenanthroline, 4,7-Me2phen = 4,7-dimethyl-1,10-phenanthroline, and 3,4,7,8-Me4phen = 3,4,7,8-tetramethyl-1,10-phenanthroline) have been synthesized and magneto-structurally investigated. The crystal structures of 1–4 contain bis(pyrazolate)(perchlorate)- (1 and 3), bis(pyrazolate)(aqua)- (2 and 3), …

Synthesis, structural, thermal, and magnetic investigations of Co(II), Ni(II), and Mn(II) pyrophosphate chains

2012

The reaction in water of cobalt(II), nickel(II) or manganese(II) chloride with 1,10-phenanthroline (phen) and sodium pyrophosphate (Na 4 P 2 O 7 ) at low pH (∼2) afforded three isostructural pyrophosphate complexes of an unprecedented one-dimensional typology, namely, {[M(phen)(H 2 O)(H 2 P 2 O 7 )]·H 2 O} n with M = Co( 1 ), Ni( 2 ) and Mn( 3 ). The di-hydrogen-pyrophosphate anion featured in these complexes adopts a rare bidentate/monodentate bridging mode leading to chain propagation. This unusual bridging pathway produces a metal–metal intra-chain separation of about 6.6–6.7 A for 1 – 3 , values much larger than the metal–metal distance across the classic bis-bidentate PPi in the parent…