SPECIFIC HEAT OF SUPERCONDUCTING 2H-NbSe2DILUTELY DOPED WITH Fe

L'action des impuretés de Fe sur les propriétés supraconductrices de NbSe2 a été étudié par des mesures de la chaleur spécifique. Les résultats sont compatibles avec la théorie d'Abrikosov-Gor'kov et indiquent que le fort champ cristallin d'anisotropie est responsable de la diminution de l'anomalie de Kondo dans ce supraconducteur à structure en couches.The effect of Fe impurities on superconducting properties of NbSe2 is examined by specific heat measurements. The results are rather consistent with the Abrikosov-Gor'kov theory and the strong crystalline anisotropy field is indicated to be responsible for the apparent quenching of the Kondo anomaly in this layered superconductor

X-ray circular magnetic dichroism at the iron K-edge in rare earth-transition metal intermetallics: experimental probe of the rare-earth magnetic moment

Submitted to Phys. Rev. LettersConsiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Thermococcus chitonophagus sp. nov., a novel, chitin-degrading hyperthermophilic archaeum from a deep-sea hydrothermal vent environment

From a hydrothermal vent site off the Mexican west coast (20°50′N, 109°06′W) at a depth of 2,600 m, a novel, hyperthermophilic, anaerobic archaeum was isolated. Cells were round to slightly irregular cocci, 1.2–2.5 μm in diameter and were motile by means of a tuft of flagella. The new isolate grew between 60 and 93°C (optimum: 85°C), from pH 3.5 to 9 (optimum: pH 6.7), and from 0.8 to 8% NaCl (optimum: 2%). The isolate was an obligate organotroph, using chitin, yeast extract, meat extract, and peptone for growth. Chitin was fermented to H2, CO2, NH3, acetate, and formate. H2S was formed in the presence of sulfur. The chitinoclastic enzyme system was oxygen-stable, cell-associated, and inducible by chitin. The cell wall was composed of a surface layer of hexameric protein complexes arranged on a p6 lattice. The core lipids consisted of glycerol diphytanyl diethers and acyclic and cyclic glycerol diphytanyl tetraethers. The G+C content was 46.5 mol%. DNA/DNA hybridization and 16S rRNA sequencing indicated that the new isolate belongs to the genusThermococcus, representing a new species,Thermococcus chitonophagus. The type strain is isoalte GC74, DSM 10152