3,038 research outputs found

    New isometry of Krall-Laguerre orthogonal polynomials in martingale spaces

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    In this paper we study how an inner product derived from an Uvarov transformation of the Laguerre weight function is used in the orthogonalization procedure of a sequence of martingales related to a Levy process. The orthogonalization is done by isometry. The resulting set of pairwise strongly orthogonal martingales involved are used as integrators in the so-called chaotic representation propertyEdmundo J. Huertas is supported by a grant from Ministerio de Ciencia e Innovación (MTM 2009-12740-C03-01), and by Fundação para a Ciência e Tecnologia (FCT), ref. SFRH/BPD/91841/2012, Portugal. Nuria Torrado is supported by Fundação para a Ciência e Tecnologia (FCT), ref. SFRH/BPD/91832/2012, Portugal. The research of Fabrizio Leisen has been partially supported by the Spanish Ministry of Science and Innovation through grant ECO2011-2570

    Semiclassical Concepts in Magnetoelectronics

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    Semiclassical theories of electron and spin transport in metallic magnetic structures are reviewed with emphasis on the role of disorder and electronic band structures in the current perpendicular to the interface plane (CPP) transport configuration.Comment: Proceedings of the NEC Symposium on "Spin-related Quantum Transport in Mesoscopic Systems", to be published in the Journal of Materials Science and Engineering

    Las bentonitas de la zona sur de Cabo de Gata (Almería). Geoquímica y Mineralogía

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    Se han estudiado las caracteristicas quimicas y mineralógicas de las bentonitas y esmectitas de esta region, asi como sus principales parametros cristalográficos y fórmulas estructurales de las esmectita

    Proximity effect-assisted absorption of spin currents in superconductors

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    The injection of pure spin current into superconductors by the dynamics of a ferromagnetic contact is studied theoretically. Taking into account suppression of the order parameter at the interfaces (inverse proximity effect) and the energy-dependence of spin-flip scattering, we determine the temperature-dependent ferromagnetic resonance linewidth broadening. Our results agree with recent experiments in Nb|permalloy bilayers [C. Bell et al., arXiv:cond-mat/0702461].Comment: 4 page

    AVOCADO: A Virtual Observatory Census to Address Dwarfs Origins

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    Dwarf galaxies are by far the most abundant of all galaxy types, yet their properties are still poorly understood -especially due to the observational challenge that their intrinsic faintness represents. AVOCADO aims at establishing firm conclusions on their formation and evolution by constructing a homogeneous, multiwavelength dataset for a statistically significant sample of several thousand nearby dwarfs (-18 < Mi < -14). Using public data and Virtual Observatory tools, we have built GALEX+SDSS+2MASS spectral energy distributions that are fitted by a library of single stellar population models. Star formation rates, stellar masses, ages and metallicities are further complemented with structural parameters that can be used to classify them morphologically. This unique dataset, coupled with a detailed characterization of each dwar's environment, allows for a fully comprehensive investigation of their origins and to track the (potential) evolutionary paths between the different dwarf types.Comment: 4 pages, 1 figure. To appear in the proceedings of IAU Symposium 277, "Tracing the Ancestry of Galaxies on the Land of our Ancestors", Carignan, Freeman, and Combes, ed

    A practical floating-gate Muller-C element using vMOS threshold gates

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    El pdf del artículo es la versión de autor.This paper presents the rationale for vMOS-based realizations of digital circuits when logic design techniques based on threshold logic gates are used. Some practical problems in the vMOS implementation of threshold gates have been identified and solved. The feasibility and versatility of the proposed technique as well as its potential as a low-cost design technique for CMOS technologies have been shown by experimental results from a multiple-input Muller C-element. The proposed new realization exhibits better performance related to delay and area and power consumption than the traditional logic implementation.Peer Reviewe

    Spin Torques in Ferromagnetic/Normal Metal Structures

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    Recent theories of spin-current-induced magnetization reversal are formulated in terms of a spin-mixing conductance GmixG^{mix}. We evaluate GmixG^{mix} from first-principles for a number of (dis)ordered interfaces between magnetic and non-magnetic materials. In multi-terminal devices, the magnetization direction of a one side of a tunnel junction or a ferromagnetic insulator can ideally be switched with negligible charge current dissipation.Comment: 4 pages, 1 figur

    Scattering theory of interface resistance in magnetic multilayers

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    The scattering theory of transport has to be applied with care in a diffuse environment. Here we discuss how the scattering matrices of heterointerfaces can be used to compute interface resistances of dirty magnetic multilayers. First principles calculations of these interface resistances agree well with experiments in the CPP (current perpendicular to the interface plane) configuration.Comment: submitted to J. Phys. D (special issue at the occasion of Prof. T. Shinjo's 60th birthday
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