1,720,956 research outputs found
ROOM TEMPERATURE MAGNETORESISTANCE IN LARGE AREA Co/Bi2Se3 BILAYERS
No full textThe area of spintronics has witnessed tremendous progress in the 21st century. During the 1980s and 1990s, the Giant and Tunnel Magnetoresistance effect dominated spintronics research with room-temperature ferromagnets(FM), metals, and insulators. Since then, the observation of several spin-based phenomena in heavy non-magnetic materials such as the Spin Hall Effects and the discovery of topological insulators have broadened the scope of spintronics research. Strong spin-orbit coupling (SOC) in topological insulators is expected to induce strong spin-orbit torques on proximal magnetic moments. This has motivated much recent interest in FM/TI systems with applications in spintronic memory and sensing. In this work, magnetron sputtered large-area Co/Bi2Se3 thin films were investigated with a custom-built magnetotransport setup. When current is passed predominantly through the Co layer we observe typical Co anisotropic magnetoresistance, but by promoting higher current density through the interface, we observe unidirectional magnetoresistance with a much larger change in resistance than Co alone. We also observe an unusual inverse current dependence. To test the contributions of each constituent material, Co/Ta and Cr/Bi2Se3 were prepared as controls, and similar observations were made in both materials, but not Co/Cr, suggesting that high SOC in the overlayer may be the driving force. While a proper understanding of our magnetoresistance data is not available at this point, the results broadly highlight the exciting prospects of observing novel phenomena in bilayer spintronic systems at room temperature
MAGNETOTRANSPORT PROPERTIES OF POLYCRYSTALLINE Mn_(3-x)Fe_xSn (x = 1, 2) THIN FILMS
Get PDFThe incredible progress of the microelectronics industry in the last several decades hasbeen primarily due to the progressive miniaturization and optimization of the MOSFET. However, the rate of this progress is becoming unsustainable by these means. Of several proposed replacements, one of the most popular ideas is to utilize electronic spin in logical processing. The discovery of Giant Magntoresistance (GMR) in layered thin film heterostructures and the subsequent development of Tunneling Magnetoresistance (TMR) devices revolutionized magnetic field sensing, which allowed magnetic domains in hard drives to get much smaller. This enabled hard drives to get denser, but because current charge-based devices are still much faster and smaller and require less energy to switch than magnetic domains, charge-based devices are still preferred for primary storage (RAM). The discoveries of Spin Orbit Torque (SOT) and Spin Transfer Torque (STT) have demonstrated that spin can be utilized for writing as well due to interactions between spin and the magnetization of a ferromagnet. Although magnetoresistive RAM (MRAM) has already been successfully implemented as a commercially available product, it remains small and expensive and is only used in specific applications. This is partially due to limitations of the individual constituent materials as spin filters or conductors, and partially due to incompatibility of adjacent crystal layers in a heterostructure. Many different types of mai terials have recently been identified as promising candidates for an optimized spin-based device. Manganese-based Heusler compounds constitute a large subset of these theoretically predicted materials due to their high perpendicular magnetic anisotropy (PMA), high curie temperatures, and low saturation fields, as well as their spin conduction, all with very similar crystal structures. In this work, I study magnetotransport and magneto-optical properties of Mn2FeSn and Fe2MnSn thin films and review properties of their parent compound Mn3Sn, which has been reported on extensively in the literature. My experimental methods involved a combination of homemade setups and sophisticated commercial tools. I may have observed a large topological Hall effect in a D019 Mn2FeSn thin film, and did observe a major substrate dependence on the properties of D019 Fe2MnSn thin films and a curious current dependence on the magnetoresistance behaviour in an Fe2MnSn thin film. This work emphasizes the sensitivity of Heusler alloy stoichiometry
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
