Purification and characterisation of a fungal alkaline phosphatase from an arbuscular mycorrhiza

* INRA URD BP 86510 21065 Dijon cedex (FRA) Diffusion du document : INRA URD BP 86510 21065 Dijon cedex (FRA) Diplôme : Dr. d'Universit

Effects of repeated applications of the fungicide "Bordeaux mixture"(copper sulfate) on the diversity of bacterial populations as estimated by PCR-RFLP analysis of 16S rDNA

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Effects of repeated applications of copper sulfate on the diversity of bacterial populations as estimated by ardra analysis

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Spin diffusion length and polarization of ferromagnetic metals measured by spin-absorption technique in lateral spin valves

International audienceWe present measurements of pure spin current absorption on lateral spin valves. By varying the width of the absorber we demonstrate that spin current absorption measurements enable to characterize efficiently the spin transport properties of ferromagnetic elements. The analytical model used to describe the measurement takes into account the polarization of the absorber. The analysis of the measurements allows thus determining the polarization and the spin diffusion length of a studied material independently, contrarily to most experiments based on lateral spin valves where those values are entangled. We report the spin transport parameters of some of the most important materials used in spinorbitronics (Co60Fe40, Ni81Fe19, Co, Pt, and Ta), at room and low (10 K) temperatures. TEXT Recent advances in spinorbitronics have evidenced the need for new characterization techniques, measuring precisely the spin-dependent material properties. Indeed, parameters such as the damping, the polarization, the spin diffusion length, the Dzyaloshinskii-Moriya interaction (DMI) or the spin Hall angle are key factors to understand and control various mechanisms: spin transfer torque 1,2,3 , spin texture dues to DMI 4,5,6 , or charge-to-spin conversion based on spin orbit coupling effects at Rashba interfaces 7,8 , in the bulk of SHE materials 9,10 , or in topological insulators 11. Among those basic material parameters, the spin diffusion length occupies a primordial role in all spin transport mechanisms. Pioneer spin transport measurements of the spin diffusion length 12,13,14 have been performed on vertical structures, using thickness dependences, but the data available on such material parameters determination are often restricted to low temperatures. Almost two decades later, the determination of short spin diffusion lengths remains difficult, for instance in ferromagnetic alloys and heavy metals. The need for precise measurement techniques has however become crucial, in particular in spinorbitronics: the * [email protected]

Exchange bias in reduced dimensions Cobalt nanocluster arrays under the influence of nanometer thin MnPt capping layers

The magnetic behavior of cobalt nanocluster arrays arranged on a boron nitride nanomesh and capped with MnPt layers of varying thickness is investigated. The magnetic properties of the arrays are found to be strongly dependent on the cobalt nanocluster size large 3 dimensional clusters of several nanometers size under the influence of only 5 nm MnPt exhibit prototypical exchange bias behavior, whereas small 2 dimensional clusters of about 1 nm in diameter show superparamagnetic behavior, however, with a strong quenching of the average cobalt magnetization. The latter effect is correlated with the formation of a stable antiferromagnetic phase at increasing MnPt thickness and is discussed in terms of the domain state exchange bias model. The quenching suggests either partial antiferromagnetic alignment of cobalt spins within a cluster or a random orientation of cobalt cluster macrospins with respect to each othe

Impacts d'applications répétées de sulfate de cuivre sur les activités et la biodiversité microbiennes

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Impacts d'applications répétées de sulfate de cuivre sur les activités et la biodiversité microbiennes. Application à l'étude des sols viticoles

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