INTERACTIONS AND PRECIPITATIONS IN DILUTE TERNARY Fe Sb M ALLOYS (M = Ti, V, Cr, Mn, Co, AND Ni)

No abstract availabl

RetroMine, or how to provide in-depth retrospective studies from Medline in a glance: the hepcidin use-case

International audienceThe rapid expansion of biomedical literature has provoked an increased development of advanced text mining tools to rapidly extract relevant events from the continuously increasing amount of knowledge published periodically in PubMed. However, bioinvestigators are still reluctant to use these tools for two reasons: i) a large volume of events is often extracted upon a query, and this volume is hard to manage, and ii) background events dominate search results and overshadow more pertinent published information, especially for domain experts. In this paper, we propose an approach that incorporates the temporal dimension of published events to the process of information extraction to improve data selection and prioritize more pertinent periodically published knowledge for scientists. Indeed, instead of providing the total knowledge associated with a PubMed query, which is usually a mix of trivial background information and non-background information, we propose a method that incorporates time and selects non background and highly relevant biological entities and events published over time for bioinvestigators. Before excluding background events from the total knowledge extracted, a quantification of their amount is also provided. This work is illustrated by a case study regarding Hepcidin gene publications over a decade, a duration that is sufficiently long enough to generate alternative views on the overall data extracted

Relativity and Magnetism in Ni-Pd and Ni-Pt Alloys

We show that the differences in the magnetic properties of Ni-Pd and Ni-Pt alloys arise mainly due to relativity. In particular, we find that the local magnetic moment of Ni increases with the addition of Pd in Ni-Pd while it decreases with the addition of Pt in Ni-Pt, as found experimentally, only if relativity is present. Our analysis is based on the effects of relativity on (i) the spin-polarized densities of states of Ni, (ii) the splitting of majority and minority spin d-band centers of Ni, and (iii) the separation between s-d band centers of Pd and Pt in Ni-Pd and Ni-Pt alloys.Comment: one figure added, a paragraph added in discussio

Electrical transport properties of bulk Nic_{c}Fe1−c_{1-c} alloys and related spin-valve systems

Within the Kubo-Greenwood formalism we use the fully relativistic, spin-polarized, screened Korringa-Kohn-Rostoker method together with the coherent-potential approximation for layered systems to calculate the resistivity for the permalloy series Ni$_{c}$Fe$_{1-c}$. We are able to reproduce the variation of the resistivity across the entire series; notably the discontinuous behavior in the vicinity of the structural phase transition from bcc to fcc. The absolute values for the resistivity are within a factor of two of the experimental data. Also the giant magnetoresistance of a series of permalloy-based spin-valve structures is estimated; we are able to reproduce the trends and values observed on prototypical spin-valve structures.Comment: 6 pages, ReVTeX + 4 figures (Encapsulated Postscript), submitted to PR

Effect of short range order on electronic and magnetic properties of disordered Co based alloys

We here study electronic structure and magnetic properties of disordered CoPd and CoPt alloys using Augmented Space Recursion technique coupled with the tight-binding linearized muffin tin orbital (TB-LMTO) method. Effect of short range ordering present in disordered phase of alloys on electronic and magnetic properties has been discussed. We present results for magnetic moments, Curie temperatures and electronic band energies with varying degrees of short range order for different concentrations of Co and try to understand and compare the magnetic properties and ordering phenomena in these systems.Comment: 15 pages,17 postscript figures,uses own style file

The quasiparticle band structures of ordered NixPt1-x

The quasiparticle band structures of the ordered L12 and L10 phases of NixPt1-x (x = 0.25, 0.5, and 0.75) have been calculated and compared to the band structures obtained using density functional theory. For each alloy, an increase in the curvature of the band structure is generally seen when the quasiparticle correction is made. Non-dispersive regions are shown to include a dispersive component under the quasiparticle correction. The quasiparticle weights are k-dependent and greater towards the Γ point. Non-linear analytical modelling of the quasiparticle correction is shown to be complex

POUVOIRS THERMOÉLECTRIQUES D'ALLIAGES DILUÉS DU NICKEL ET DU COBALT AVEC DES ÉLÉMENTS DE TRANSITION

Les pouvoirs thermoélectriques (P. T. E.) d'alliages dilués du nickel et du cobalt avec des éléments des trois premières séries de transition ont été mesurés dans deux domaines de température : de 1,2 à 4,2 °K et de 77 à 300 °K. Aux basses températures, le P. T. E. mesuré (S0) est proportionnel à la température et généralement, indépendant de la concentration en impuretés ; on détermine ainsi le P. T. E. associé à l'impureté seule : S0/T. Aux températures suffisamment élevées (contribution du "phonon-drag" négligeable) le P. T. E. varie encore linéairement avec la température mais dépend fortement de la concentration. On utilise cette dépendance en concentration à une température donnée (295 °K) pour analyser les données expérimentales dans un modèle de conduction à deux bandes indépendantes sσ (σ = ↑, ↓). Ce modèle néglige toute variation de la structure électronique des impuretés avec la température. On en déduit, les P. T. E. et les résistivités associés à chaque bande sσ à la fois pour la matrice et pour l'impureté. Les résultats obtenus confirment le schéma d'état lié virtuel s"up"d"up" déjà proposé pour ces alliages à partir des mesures d'aimantation et de résistivité.Thermoelectric power (T. E. P.) measurements of dilute alloys of nickel and cobalt with transition elements have been carried out in two temperature ranges : between 1.5 and 4.2 °K, and between 77 and 300 °K. At low temperatures, the measured T. E. P. (S0) is proportionnal to the temperature, and generally independent of the impurity concentration ; the T. E. P. araising from the impurity alone (S0/T) is deduced. At sufficiently high temperatures (phonondrag contribution is negligible) the temperature dependence of T. E. P. is still linear, but depends on concentration. We used this concentration dependence at 295 °K to analyse the experimental data in an independent two-band conduction model, assuming as negligible the variation of impurity electronic structure with temperature. The T. E. P. and resistivities associated with each band "sσ" for the matrix and the impurity are deduced. The obtained results check the previous model and the "s"up"d"down"" virtual bound state scheme