1,720,988 research outputs found
Unusual first-order magnetic phase transition and large magnetocaloric effect in Nd2In
Get PDFA large magnetocaloric effect with its maximum near the boiling point of natural gas occurs in a rare-earth intermetallic compound Nd2In. While behaviors of physical properties indicate that paramagnetic-ferromagnetic transformation supporting the large magnetocaloric effect is first order in nature, temperature-dependent crys-tallographic study reveals no changes in lattice symmetry and lack of discontinuities either in phase volume or lattice parameters. The borderline first-order nature of phase transformation in Nd2In is markedly different from conventional first-order magnetic transitions occurring in other members of the family - isostructural Pr2In and nonisostructural Eu2In.This article is published as Biswas, Anis, Rajiv K. Chouhan, Alex Thayer, Yaroslav Mudryk, Ihor Z. Hlova, Oleksandr Dolotko, and Vitalij K. Pecharsky. "Unusual first-order magnetic phase transition and large magnetocaloric effect in Nd 2 In." Physical Review Materials 6, no. 11 (2022): 114406.
DOI: 10.1103/PhysRevMaterials.6.114406.
Copyright 2022 American Physical Society.
Posted with permission.
DOE Contract Number(s): AC02-07CH1135
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
Designed materials with the giant magnetocaloric effect near room temperature
Get PDFThe coupling between structural and magnetic degrees of freedom is crucial for realization of interesting physical phenomena associated with magneto-structural transformations resembling austenite-to-martensite transitions. Despite substantial efforts in design and discovery of materials with strong magnetocaloric effects, majority of viable candidates are composed of non-earth-abundant and toxic elements, while others involve challenging syntheses and post processing. Guided by advanced density functional theory calculation, we report a new family of compounds, i.e., Mn0.5Fe0.5NiSi1-xAlx [x = 0.045–0.07] exhibiting a giant magnetocaloric effect (MCE) that is tunable near room temperature. Their MCE functionality arises from a distinct magneto-structural transformation between a paramagnetic hexagonal Ni2In-type phase and ferromagnetic orthorhombic TiNiSi-type phase that can be actuated by magnetic field and/or pressure. As the transition is sensitive to external hydrostatic pressure, the same materials should also exhibit a strong barocaloric response in addition to the giant MCE.This is a manuscript of an article published as Biswas, Anis, Arjun K. Pathak, Nikolai A. Zarkevich, Xubo Liu, Yaroslav Mudryk, Viktor Balema, Duane D. Johnson, and Vitalij K. Pecharsky. "Designed materials with the giant magnetocaloric effect near room temperature." Acta Materialia 180 (2019): 341-348. DOI: 10.1016/j.actamat.2019.09.023. Posted with permission.</p
Exceptional magnetic and magnetoelastic behavior of rare-earth non-centrosymmetric Sm7Pd3
No full textMagnetic compounds possessing an intrinsic combination of near-zero magnetization with high magnetic anisotropy are highly desirable for spinronic applications and memory recording. A comprehensive study of Sm7Pd3 binary compound uncovered a unique combination of strong magnetoelastic behavior, very low net magnetization, and exceptionally high magnetic coercivity. The temperature-dependent X-ray synchrotron powder diffraction study indicates the abrupt changes in the compound’s lattice parameters at the magnetic ordering temperature of TC= 167 K, although the crystal structure remains non-centrosymmetric hexagonal Th7Fe3-type down to 6 K. Density functional theory calculations confirm high intrinsic magnetocrystalline anisotropy of Sm7Pd3, which explains the extremely large coercivity of the polycrystalline sample, up to Hcr = 130 kOe at 2 K. This discovery brings to life a novel class of highly anisotropic materials that are distinctly different from known spintronic materials, making them interesting future systems for magnetic memory research.This is a manuscript of an article published as Biswas, Anis, Rajiv K. Chouhan, Oleksandr Dolotko, Pietro Manfrinetti, Saul Lapidus, Deborah L. Schlagel, and Yaroslav Mudryk. "Exceptional magnetic and magnetoelastic behavior of rare-earth non-centrosymmetric Sm7Pd3." Acta Materialia 265 (2024): 119630. doi: https://doi.org/10.1016/j.actamat.2023.119630
Correlating Crystallography, Magnetism, and Electronic Structure Across Anhysteretic First-Order Phase Transition in Pr2In
Get PDFTemperature-dependent powder X-ray diffraction and magnetization measurements of Pr2In conclusively prove that the unusual anhysteretic first-order paramagnetic-ferromagnetic phase transition in the compound is related to concurrent changes in both the magnetic and crystallographic lattices. At the same time, the hexagonal Ni2In-type structure is stable at least between 6 and 298 K, including at TC = ∼57 K. From the density functional theory calculations, the electronic structure of the compound is extraordinarily sensitive to minor changes in lattice parameters that occur across the phase transition, revealing the origin of strong magnetoelastic coupling. In the vicinity of TC, the maximum entropy change, ΔSMax = −16 J Kg−1 K−1 induced by a moderate magnetic field change of 20 kOe (ΔSMax = −20 J Kg−1 K−1 for 50 kOe magnetic field change) is comparable to other known potentially functional materials demonstrating large cryogenic magnetocaloric effect.This is a manuscript of an article published as Biswas, Anis, Rajiv K. Chouhan, O. Dolotko, A. Thayer, S. Lapidus, Y. Mudryk, and V. K. Pecharsky. "Correlating Crystallography, Magnetism, and Electronic Structure Across Anhysteretic First-Order Phase Transition in Pr2In." ECS Journal of Solid State Science and Technology 11, no. 4 (2022): 043005.
DOI: 10.1149/2162-8777/ac611d.
Copyright 2022 IOP Publishing Ltd.
Posted with permission.
DOE Contract Number(s): AC02-07CH11358; AC02-06CH11357
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
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