5,913 research outputs found
Nanoscopic processes of Current Induced Switching in thin tunnel junctions
In magnetic nanostructures one usually uses a magnetic field to commute
between two resistance (R) states. A less common but technologically more
interesting alternative to achieve R-switching is to use an electrical current,
preferably of low intensity. Such Current Induced Switching (CIS) was recently
observed in thin magnetic tunnel junctions, and attributed to electromigration
of atoms into/out of the insulator. Here we study the Current Induced
Switching, electrical resistance, and magnetoresistance of thin
MnIr/CoFe/AlO/CoFe tunnel junctions. The CIS effect at room temperature
amounts to 6.9% R-change between the high and low states and is attributed to
nanostructural rearrangements of metallic ions in the electrode/barrier
interfaces. After switching to the low R-state some electro-migrated ions
return to their initial sites through two different energy channels. A low
(high) energy barrier of 0.13 eV (0.85 eV) was estimated. Ionic
electromigration then occurs through two microscopic processes associated with
different types of ions sites/defects. Measurements under an external magnetic
field showed an additional intermediate R-state due to the simultaneous
conjugation of the MR (magnetic) and CIS (structural) effects.Comment: 6 pages, 4 figure
Open Space – a collaborative process for facilitating Tourism IT partnerships
The success of IT projects depends on the success of the partnerships on which they are based. However past research by the author has identified a significant rate of failure in these partnerships, predominantly due to an overly technical mindset, leading to the question: “how do we ensure that, as technological solutions are implemented within tourism, due consideration is given to human-centred issues?” The tourism partnership literature is explored for additional insights revealing that issues connected with power, participation and normative positions play a major role. The method, Open Space, is investigated for its ability to engage stakeholders in free and open debate. This paper reports on a one-day Open Space event sponsored by two major intermediaries in the UK travel industry who wanted to consult their business partners. Both the running of the event and its results reveal how Open Space has the potential to address some of the weaknesses associated with tourism partnerships
Equilibrium random-field Ising critical scattering in the antiferromagnet Fe(0.93)Zn(0.07)F2
It has long been believed that equilibrium random-field Ising model (RFIM)
critical scattering studies are not feasible in dilute antiferromagnets close
to and below Tc(H) because of severe non-equilibrium effects. The high magnetic
concentration Ising antiferromagnet Fe(0.93)Zn(0.07)F2, however, does provide
equilibrium behavior. We have employed scaling techniques to extract the
universal equilibrium scattering line shape, critical exponents nu = 0.87 +-
0.07 and eta = 0.20 +- 0.05, and amplitude ratios of this RFIM system.Comment: 4 pages, 1 figure, minor revision
Approach to competences, human development and higher education
Tendo como fundamento a psicologia do desenvolvimento humano, apresenta-se, neste artigo, uma ampliação conceitual à compreensão de competência. Esse é um termo polissêmico, com multiplicidade de concepções epistemológicas, éticas e ideológicas que imprimem complexidade aos processos formativos, especialmente em relação à formação pessoal e profissional na educação superior. Defende-se a noção de competência ancorada na mobilização intencional de diversos recursos próprios ao desenvolvimento humano: processos psicológicos, comportamentos, conhecimentos, afetos, crenças, habilidades, escolhas éticas e estéticas, que devem ser mobilizados pelo sujeito. Apresenta-se, a partir dessa ampliação, uma categorização de competências transversais e possibilidades para sua avaliação. A reflexão pode fundamentar uma atuação crítica de psicólogos e educadores para a mediação do desenvolvimento de competências dos atores do ensino superior.Grounded on human development psychology, this paper presents a conceptual expansion of the understanding about competence. This is a polysemic construct, with a wide range of epistemological, ethical and ideological concepts that reinforce the complexity of training processes, especially in relation to personal and professional training in the context of higher education. This paper defends the notion of competence rooted in intentional mobilization of various resources inherent to human development: psychological processes, behaviors, knowledge, emotions, beliefs, aptitudes, ethical and aesthetic choices that the subject must mobilize. From this conceptual expansion, a categorization of transversal competences and possibilities of assessment are presented. Analyses can support critical actions of psychologists and educators to mediate the development of competences of higher education actors.info:eu-repo/semantics/publishedVersio
Caracterização isotópica em água de poço e tanques de piscicultura no município de Petrolina, PE- Semiárido brasileiro.
Diffusion-Limited Annihilation with Initially Separated Reactants
A diffusion-limited annihilation process, A+B->0, with species initially
separated in space is investigated. A heuristic argument suggests the form of
the reaction rate in dimensions less or equal to the upper critical dimension
. Using this reaction rate we find that the width of the reaction front
grows as in one dimension and as in two
dimensions.Comment: 9 pages, Plain Te
- …