1,720,979 research outputs found
Local characterization of a heavy-fermion superconductor via sub-Kelvin magnetic force microscopy
No full textUsing magnetic force microscopy operating at sub-Kelvin temperatures, we characterize the heavy fermion superconductor CeCoIn5. We pinpoint the absolute London penetration depth of lambda ( 0 ) = 435 +/- 20 nm and report its temperature dependence, which is closely linked to the symmetry of the superconducting gap. In addition, we directly measure the pinning force of individual Abrikosov vortices and estimate the critical current density of j c = 9 x 10 4A/cm(2). In contrast to the related, well-established tunnel diode oscillator technique, our method is capable of resolving inhomogeneities locally on the micrometer scale at ultra-low temperature.11Nsciescopu
Spatially resolved penetration depth measurements and vortex manipulation in the ferromagnetic superconductor ErNi2 B2C
Full text linkWe present a local probe study of the magnetic superconductor ErNi2B2C, using magnetic force microscopy at sub-Kelvin temperatures. ErNi2B2C is an ideal system to explore the effects of concomitant superconductivity and ferromagnetism. At 500 mK, far below the transition to a weakly ferromagnetic state, we directly observe a structured magnetic background on the micrometer scale. We determine spatially resolved absolute values of the magnetic penetration depth λ and study its temperature dependence as the system undergoes magnetic phase transitions from paramagnetic to antiferromagnetic, and to weak ferromagnetic, all within the superconducting regime. In addition, we estimate the absolute pinning force of Abrikosov vortices, which shows a position dependence and temperature dependence as well, and discuss the possibility of the purported spontaneous vortex formation.This article is published as Wulferding, Dirk, Ilkyu Yang, Jinho Yang, Minkyung Lee, Hee Cheul Choi, Sergey L. Bud'ko, Paul C. Canfield, Han Woong Yeom, and Jeehoon Kim. "Spatially resolved penetration depth measurements and vortex manipulation in the ferromagnetic superconductor ErNi2B2C." Physical Review B 92, no. 1 (2015): 014517. DOI: 10.1103/PhysRevB.92.014517. Posted with permission.</p
Fingerprints for anisotropic Kondo lattice behavior in the quasiparticle dynamics of the kagome metal NiIn
Full text linkWe present a temperature- and polarization-resolved phononic and electronic
Raman scattering study in combination with the first-principles calculations on
the kagome metal NiIn with anisotropic transport properties and non-Fermi
liquid behavior. At temperatures below 50 K and down to 2 K, several Raman
phonon modes, including particularly an interlayer shear mode, exhibit
appreciable frequency and linewidth renormalization, reminiscent of the onset
of the Kondo screening without an accompanying structural or magnetic phase
transition. In addition, a low-energy electronic continuum observed in
polarization perpendicular to the kagome planes reveals strong temperature
dependence below 50 K, implying thermal depletion of incoherent quasiparticles,
while the in-plane continuum remains invariant. These concomitant electronic
and phononic Raman signatures suggest that NiIn undergoes an anisotropic
electronic crossover from an incoherent to a coherent Kondo lattice regime
below 50 K. We discuss the origin of the anisotropic incoherent-coherent
crossover in association with the possible anisotropic Kondo hybridization
involving localized Ni- flat-band electrons.Comment: 18 pages, 6 figures; published in Phys. Rev.
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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