1,721,079 research outputs found
Thin Films and Superlattice Synthesis
No full textThin film and superlattice deposition of perovskite and related mixed oxides for applications is an emerging and highly active field of research that is attracting increasing attention, because of their various technologically important properties in the strategic fields of environmental and sustainable energy applications. This chapter reviews the most common deposition techniques, namely, molecular beam epitaxy, pulsed laser deposition, and sputtering. Their potentials for the growth of epitaxial layers with desired properties will be compared. Several examples of thin films and heterostructures of complex oxides and their relevant properties will be discussed with respect to the growth process
High Tc superconducting oxycarbonate thin films grown by laser ablation : Promising new materials
No full textSuperconducting thin films of copper oxycarbonates, with the general composition (CaCuO2)m(Ba2-xAxCuO 2CO3)n (A=Ca,Sr), have been synthesized for the first time using the pulsed laser deposition technique. Via a single target system, i.e. a Ba2Ca3Cu4Ox target, the film exhibits a Tc(onset) of 110K. The m=0 member of the family, Ba2-xAxCuO2CO3, has also been studied. Structures and structural mechanisms are presented
Pulsed laser deposition of Ba(2-x)A(x)CuO(2)CO(3) (A=Ca, Sr) thin films, m=0 member of the series (CaCuO2)(m)(Ba(2-x)A(x)CuO(2)CO(3))(n) (A=Ca, Sr)
No full textCopper oxycarbonate thin films of the (CaCuO2)(m)(Ba(2-x)A(x)CuO(2)CO(3))(n) (A = Ca, Sr) system have been deposited, using the pulsed laser deposition (PLD) technique, on (100) LaAlO3 and (110) NdGaO3 substrates. The m = 0 member of the family, Ba2-xSrxCuO2CO3 (x = 0.1 and x = 0.4) has been deposited in a selective way for the first time on both LaAlO3 and NdGaO3. The best results have been obtained for NdGaO3 substrates, but a double orientation of the film, [001] and [110], is found by transmission electron microscopy (TEM) for x = 0.4. Ba2-xCaxCuO2CO3 (x = 0.2) has also been studied. At a deposition temperature of 620 degrees C, a Ba2CuO2CO3 (B2CC) type structure is stabilized, whereas at 680 degrees C another perovskite is isolated. Attempts to deposit the member (m = 1, n = 1, x = 0) of the family, i.e., Ba2CaCu2O4CO3, on LaAlO3 using a single multiphase sintered ceramic target led to the formation of a B2CC type structure (m = 0) coherently intergrown with CaCu2O3 and Ca2CuO3 extended defects. The structures and structural mechanisms are discussed. No diamagnetic transition was observed in any of these films down to 5 K
Films minces d'oxycarbonates preparees par ablation laser pulsee : du systeme monocible au systeme multicible
No full textThe microstructural study of superconductor thin films with general formula: (CaCuO2)m(Ba2CuO2CO 3)n, grown from a single target, has shown that these films exhibited numerous intergrowth phases. Such films can not be used for precise physical studies. To obtain a regular stacking along a growth direction perpendicular to the substrate a multi-target system has to be used. The preliminary results of this study are presented herein
Ba2-xSrxCuO2CO3: A Series of Oxycarbonate Thin Films Grown by Pulsed Laser Deposition on NdGaO3 Substrates
No full textMonophasic thin films of the oxycarbonates Ba2-xSrxCuO2CO3 have been grown by pulsed laser deposition on [110]-oriented NdGaO3 substrates for x = 2, 1.6, 0.9, 0.4, and 0.3. A systematic study of these films by X-ray diffraction and transmission electron microscopy shows that the film orientation varies from a-axis or [110] orientation (copper layers perpendicular to the substrate) to a c-axis or [001] orientation (copper layers parallel to the substrate) as x decreases. Sr2CuO2CO3 (x = 2) is indeed a-axis oriented, whereas for 0.4 < x < 1.6 these films have a [110] orientation, and finally for x = 1.6-1.7 the films exhibit c-axis, [110]- and [110]-oriented domains. The factors which influence the orientation of these films are discussed
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
Oxycarbonates thin films grown by pulsed laser deposition: from a single target system to a multi-target system
No full textThe microstructural study of superconductor thin films with general formula: (CaCuO2)(m)(Ba2CuO2CO3)(n), grown from a single target, has shown that these films exhibited numerous intergrowth phases. Such films can not be used for precise physical studies. To obtain a regular stacking along a growth direction perpendicular to the substrate a multi-target system has to be used. The preliminary results of this study are presented herein
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
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