Origin of the inverse spin-switch behavior in manganite/cuprate/manganite trilayers

We studied ferromagnet/superconductor/ferromagnet trilayers based on La_(0.7)Ca_(0.3)MnO_(3) manganite and YBa_(2)Cu_(3)O_(7−δ) (YBCO) high-T_(c) cuprate with magnetoresistance and magnetization measurements. We find an inverse superconducting spin-switch behavior, where superconductivity is favored for parallel alignment of the magnetization in the ferromagnetic layers. We argue that this inverse superconducting spin switch originates from the transmission of spin-polarized carriers into the superconductor. In this picture, the thickness dependence of the magnetoresistance yields the spin-diffusion length in YBCO as 13 nm. A comparison of bilayers and trilayers allows ruling out the effect of the stray fields of the domain structure of the ferromagnet as the source of the inverse superconducting spin switch

Electrical conductivity and oxygen diffusion in Bifevox.

© Sociedad Española de Cerámica y Vidrio. National Congress of Materials (7. 2002. Madrid).Presentamos medidas de la conductividad eléctrica del sistema BIFEVOX Bi_(4)V_(2-x)Fe_(x)O_(11-y)(0≤x≤0.9;0≤y≤1), en el que se realiza la sustitución de iones V (IV) por Fe (III) de forma sistemática. La conductividad muestra un comportamiento potencial con la frecuencia, descrito por σ*(ω)=σ_(dc)[1+(jω/ω_(p))^(n)], y conocido como respuesta dieléctrica universal. Análogamente, el módulo eléctrico presenta picos asimétricos, cuya función de relajación en el dominio del tiempo puede describirse mediante exponenciales “estiradas” de la forma φ(t)=exp(-(t/τ_(σ))^(β)). β da cuenta del grado de correlación del transporte iónico, siendo su valor, β=0.56±0.03, casi independiente de la temperatura y del contenido en Fe. Con el aumento en el contenido de Fe, la conductividad disminuye exponencialmente y la energía de activación del proceso de conducción aumenta de 0.20 a 0.97 eV. Estos resultados se discuten en términos de la ordenación de vacantes oxígeno al dopar con Fe (III).We present electrical conductivity measurements of BIFEVOX Bi_(4)V_(2-x)Fe_(x)O_(11-y)(0≤x≤0.9; 0≤y≤1), in which V (IV) ions have been systematically substituted by Fe (III) ions. Conductivity shows a power law frequency dependence described by the form σ*(ω)=σ_(dc)[1+(jω/ω_(p))^(n)], known as universal dynamic response. Conversely, the electric modulus shows asymmetric peaks, characterized by stretched exponentials relaxation functions in time domain of the form φ(t)=exp(-(t/τ_(σ))^(β)). β is determined by the degree of correlation in the ionic motion. It´s value, β=0.56±0.03, is almost independent of temperature and iron content. Increasing Fe content leads to an exponential decrease of the conductivity and to an increase of the activation energy of the conduction process from 0.20 to 0.97 eV. These results are discussed in terms of oxygen vacancy ordering upon Fe (III) substitution.Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEpu

Using Imperfect Information in Online Social Systems: Applications and Measures of Betweenness

Online social software systems enable individuals to build representations of their network of social ties, and such information can be used for the analysis of network structure and the position of individuals in the network. However, social ties representing relationships as “friendship” have intensity or strength as an intrinsic, essential feature, and this needs to be taken into account in network models. This paper reports on fuzzy techniques that deal with imprecise information on the strength of social ties, and provides an extended model of brokerage that accounts for such imprecise information

Communications in Computer and Information Science: Preface

Netsis;Bilgiturk Teknoloji;Agro-Know Technologies;Technology and Sustainability Research Institute (TSRI)5th International Conference on Metadata and Semantic Research, MTSR 2011 --12 October 2011 through 14 October 2011 -- Izmir --[No abstract available

Skill Modelling for Digital Factories

Part 5: Industry 4.0 - Digital TwinInternational audienceIn the past two decades, the use of ontologies has been proven to be an effective tool for enriching existing information systems in the digital data modelling domain and exploiting those assets for semantic interoperability. Despite the presence of many databases for industrial skills and professions, a formal representation, namely, an ontology, which meets the requirements of an existing tool for skill and capability analysis called CaMDiF is missing. In this research, the MSDL ontology, used by the tool in its initial version, is extended by importing modules of upper level and mid level ontologies (BFO and Agent Ontology) and by developing a new ontology for industry skills and professions based on an existing non-ontological resource (O*NET). As a result, an overview of the enriched data structure is provided along with some discussions on a use case related to skill analysis enabled by the new CaMDiF’s skill modelling features

USABILITY EVALUATION OF ONTOLOGY EDITORS

Abstract: Ontology editors are software tools that allow the creation and maintenance of ontologies through a graphical user interface. As the Semantic Web effort grows, a larger community of users for this kind of tools is expected. New users include people not specifically skilled in the use of ontology formalisms. In consequence, the usability of ontology editors can be viewed as a key adoption precondition for Semantic Web technologies. In this paper, the usability evaluation of several representative ontology editors is described. This evaluation is carried out by combining a heuristic pre-assessment and a subsequent user-testing phase. The target population comprises people with no specific ontology-creation skills that have a general knowledge about domain modelling. The problems found point out that, for this kind of users, current editors are adequate for the creation and maintenance of simple ontologies, but also that there is room for improvement, especially in browsing mechanisms, help systems and visualization metaphors

A model for predicting the Ms temperatures of steels.

Using neural networks in a Bayesian framework, a model has been derived for the Ms temperature of steels over a wide range of compositions. By its design and by use of a more extensive database, this model improves over existing ones, by its accuracy and its ability to avoid wild predictions.NPL for provision of MTDATA and Neuromat for provision of the Model Manager.Peer reviewe

Conductividad eléctrica y difusión de oxígeno en el sistema Bifevox

Presentamos medidas de la conductividad eléctrica del sistema BIFEVOX Bi_(4)V_(2-x)Fe_(x)O_(11-y)(0≤x≤0.9;0≤y≤1), en el que se realiza la sustitución de iones V (IV) por Fe (III) de forma sistemática. La conductividad muestra un comportamiento potencial con la frecuencia, descrito por σ*(ω)=σ_(dc)[1+(jω/ω_(p))^(n)], y conocido como respuesta dieléctrica universal. Análogamente, el módulo eléctrico presenta picos asimétricos, cuya función de relajación en el dominio del tiempo puede describirse mediante exponenciales “estiradas” de la forma φ(t)=exp(-(t/τ_(σ))^(β)). β da cuenta del grado de correlación del transporte iónico, siendo su valor, β=0.56±0.03, casi independiente de la temperatura y del contenido en Fe. Con el aumento en el contenido de Fe, la conductividad disminuye exponencialmente y la energía de activación del proceso de conducción aumenta de 0.20 a 0.97 eV. Estos resultados se discuten en términos de la ordenación de vacantes oxígeno al dopar con Fe (III)