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Focused ion beam induced swelling in MgO(001)
No full textThe ability to prepare ordered arrays of micro/nano sized
magnetic elements off ers the chance to investigate magnetic
properties at length scales previously inaccessible.
Patterning of extended magnetic layers or multilayers by
Focused Ion Beam (FIB) is one of the most powerful approaches
for nano-structuration on a large variety of materials,
due to its high spatial resolution, good process control
and elevated fl exibility.
MgO(001) is as a good substrate for UHV epitaxial growth of
multilayers of magnetic interest, such as Fe/NiO: it is magnetically
inert, it has a small lattice mismatch with respect
to NiO and it is cheap and easy to prepare.
In the present work we analyze ion-induced swelling effects
on MgO(001) single crystals as they could infl uence
the structure, morphology and, consequently, the properties
of magnetic arrays prepared by FIB patterning of magnetic
layers on MgO crystalline substrates.
We studied by AFM the ions eff ects on the morphology of
one micron size square dots array obtained on a 5–10 nm
MgO/10 nm Fe/MgO(001) multilayers. A Fe interlayer has
been deposited to avoid electronic charging that restricts
ion beam effi ciency. 30 keV, 5x1016 Ga+cm-2 bombardment
leads to a signifi cant swelling eff ect (4–6 nm protrusion) on
the patterned areas. Electron diff raction and Auger depth
profi le measurements suggest that the observed swelling
mainly originates from MgO structural damage
Focused ion beam induced swelling in MgO(0 0 1)
No full textThe interplay between swelling and milling phenomena in determining the morphology of Focused Ion Beam (FIB)-processed MgO(001) was investigated by atomic force microscopy. At the early stages of ion irradiation.. before millinig erosion-is observed, MgO shows a relevant swelling behaviour with protrusion of the bombarded areas up to 6 nm for a dose of 5 x 10(16) ions cm(-2). The effect is mainly ascribed to subsurface defect accumulation, while the low Ga ions concentration, as measured by in-depth Auger analysis, seems to exclude a contribution from ion implantation. In order to explain and control the morphology of Fe/NiO FIB patterned sub-micron structures on MgO substrates, we have also investigated FIB effects on Fe(001) and NiO(001) single crystals. Absent or negligible swelling has been observed on these materials. (c) 2006 Elsevier B.V. All rights reserved
Swelling process induced by Focused Ion Beam on magnetic layers
No full textThe ability to prepare ordered arrays of micro/nano sized magnetic elements offers the chance to investigate magnetic properties at length scales previously inaccessible. Bi-dimensional ordered array of magnetic dots can be obtained through a number of different techniques.
Patterning of extended magnetic layers or multilayers by Focused Ion Beam (FIB) is one of the most powerful approaches for nano-structuration on a large variety of materials due to the high spatial resolution, good process control and elevated flexibility. This enables a very high accuracy to be achieved in the refinement (shape, sharpness, orientation and dimension) of each individual element and of the separation between the elements. On the other hand ion interactions with solids produce several damage effects. These effects can be very severe in the case of crystalline solids and of nano-sized elements, and can influence magnetic properties of the systems (magneto-crystalline and configurational anisotropy).
We studied by AFM and Depth Profile Auger analysis the ions effect on a submicron scale dots array obtained on a 10nm Fe/10nm NiO/MgO(001) multilayer capped with 10nm of MgO. Ion-induced local damage leads to a significant swelling effect on the nano-structures [1]. Our measurements suggest that swelling observed on the multilayer originates from substrate ion irradiation.
Transmission Electron Microscopy and diffraction technique measurements should give structural information and clarify the relations between ion induced damage and swelling effect.
[1] G. C. Gazzadi, P. Luches, S. F. Contri, A. di Bona, S. Valeri, Nucl. Instr. Meth. B 230 (2005) 512
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
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