Intrinsic switching field distribution of arrays of Ni80Fe20 nanowires probed by in situ\mathit{in\, situ} magnetic force microscopy

The progress of magnetization reversal of weakly packed ferromagnetic Ni80Fe20 nanowire arrays of different diameters (40, 50, 70 and 100 nm) electrodeposited in polycarbonate membranes was studied by magnetic force microscopy (MFM). For such a low packing density of nanomagnets, the dipolar interactions between neighbouring wires can be neglected. The intrinsic switching field distribution has been extracted from in situ MFM images and its width was found to be considerably smaller than for densely packed nanowire arrays.Comment: 4 pages, 5 figures. To appear in Journal of Superconductivity and Novel Magnetis

Magnetic force microscopy investigation of arrays of nickel nanowires and nanotubes

The magnetic properties of arrays of nanowires (NWs) and nanotubes (NTs), 150 nm in diameter, electrodeposited inside nanoporous polycarbonate membranes are investigated. The comparison of the nanoscopic magnetic force microscopy (MFM) imaging and the macroscopic behavior as measured by alternating gradient force magnetometry (AGFM) is made. It is shown that MFM is a complementary technique that provides an understanding of the magnetization reversal characteristics at the microscopic scale of individual nanostructures. The local hysteresis loops have been extracted by MFM measurements. The influence of the shape of such elongated nanostructures on the dipolar coupling and consequently on the squareness of the hysteresis curves is demonstrated. It is shown that the nanowires exhibit stronger magnetic interactions than nanotubes. The non-uniformity of the magnetization states is also revealed by combining the MFM and AGFM measurements.Comment: 7 pages, 5 figure

O papel e os desafios do fórum no enfoque do desenvolvimento territorial.

neste artigo apresenta a discussão, os objetivos, o resultado e o funcionamento do fórum como espaço de novas governanças nos territórios, o qual se constitui um dos eixos no projeto desenvolvido pela Embrapa, Cirad e Fao, em quatro município do Piauí e Pernambuco

Evaluation du developpement territorial comme processus d'innovation et d'institutionnalisation: le cas du Territoire du Alto Sertão do Piauí e Pernambuco au Nordeste du Brésil.

Du fait de leur transversalité et de leur objet, l'évaluation des politiques de développement territorial ne peut pas s'appuyer su les outils utilisés pour évaluer les politiques sectorielles

Le consortium intermunicipal : un dispositif efficace de gouvernance territoriale?: le cas d'une expérience dans le Nordeste du Brésil.

Contexto territorial de quatro município do estado de Pernambuco e Piauí; Mobilização e Conscientização: um território em construção; Projeto territorial

Le développement territorial durable : le cas d'une expérience dans le Nordeste du Brésil.

Cette communication traite d'une expérience de recherche-action de développement territorial durable au niveau du territoire du Alto Sertão du Oiaui et du Pernambuco dans le Nordeste du Brésil

Effects of nonzero photon momentum in (\gamma,2e) processes

We study the effects of nonzero photon momentum on the triply-differential cross section for (\gamma,2e) processes. Due to the low value of the photon momentum, these effects are weak and manifest only in special kinematical conditions like the back-to-back emission of the electrons with equal energy sharing. Helium and a few light helium-like ions are treated in detail. Quite unexpectedly, the magnitude of these effects is maximal for relatively small photon energies. However, although this effect on the TDCS remains rather small, of the order of a few mbarn eV^{-1} sr^{-2}, it is sufficient to be observed experimentally.Comment: 8 pages, 7 figures, 1 tabl

Les agents de développement durable: de nouveaux acteurs pour une nouvelle gouvernance technologique territoriale. L'exemple du territoire do Alto Sertão do Pernambuco e Piaui dans le Nordeste Brésilien.

L'expérience esr une recherche-action de développement territorial avec un axe technique important, visant la consolidation des systèmes de production

Current-voltage characteristics of quasi-one-dimensional superconductors: An S-curve in the constant voltage regime

Applying a constant voltage to superconducting nanowires we find that its IV-characteristic exhibits an unusual S-behavior. This behavior is the direct consequence of the dynamics of the superconducting condensate and of the existence of two different critical currents: j_{c2} at which the pure superconducting state becomes unstable and j_{c1}<j_{c2} at which the phase slip state is realized in the system.Comment: 4 pages, 5 figures, replaced with minor change