Growth and characterization of CoO ultra thin films

In this report we present the growth process of the cobalt oxide system using reactive electron beam deposition. In that technique, a target of metallic cobalt is evaporated and its atoms are in-flight oxidized in an oxygen rich reactive atmosphere before reaching the surface of the substrate. With a trial and error procedure the deposition parameters have been optimized to obtain the correct stoichiometry and crystalline phase. The evaporation conditions to achieve the correct cobalt oxide salt rock structure, when evaporating over amorphous silicon nitride, are: 525 K of substrate temperature, 2.5·10-4 mbar of oxygen partial pressure and 1 Å/s of evaporation rate. Once the parameters were optimized a set of ultra thin film ranging from samples of 1 nm of nominal thickness to 20nm thick and bulk samples were grown. With the aim to characterize the samples and study their microstructure and morphology, X-ray diffraction, transmission electron microscopy, electron diffraction, energy dispersive X-ray spectroscopy and quasi-adiabatic nanocalorimetry techniques are utilised. The final results show a size dependent effect of the antiferromagnetic transition. Its Néel temperature becomes depressed as the size of the grains forming the layer decreases.

Proposal for the analysis of a video game, a film, and their relationship : Silent Hill as a subject of the horror genre

Aquest treball de recerca fa un estudi comparatiu del videojoc de terror amb el seu homòleg cinematogràfic. L’objectiu és arribar a saber si els dos mitjans de comunicació usen les mateixes tècniques per transmetre les seves històries i per crear suspens. Aquesta investigació és només una part d'un estudi més ampli amb el que es pretén tenir un coneixement més aprofundit de les emocions de la gent i les reaccions que els provoca un videojoc de terror en comparació amb la visualització de l'adaptació cinematogràfica del corresponent videojoc.

La Implicació de Hollywood en la Segunda Guerra Mundial: el cas Why we fight

Why we fight és un grup de set pel·lícules de format documental que van formar part d’un ampli programa d’informació, formació i propaganda impulsat per l’exèrcit nord-americà, en el moment en què els Estats Units ja s’havien implicat en la Segona Guerra Mundial. És també un dels més reeixits exercicis de retòrica cinematogràfica nord-americana d’aquell període que permet analitzar com els països democràtics van gestionar qüestions tan compromeses com la propaganda de guerra. La pretensió d’aquest treball de recerca és aprofundir en la complexitat ideològica i formal de la sèrie, que faci possible descobrir-ne els orígens, els objectius i la manera com aquests van ser assolits per un grup d’especialistes cinematogràfics, coordinats pel director Frank Capra, tots els quals havien triomfat fins llavors a Hollywood

Critical ruptures in a bundle of slowly relaxing fibers

We study the damage enhanced creep rupture of disordered materials by means of a fiber bundle model. Broken fibers undergo a slow stress relaxation modeled by a Maxwell element whose stress exponent m can vary in a broad range. Under global load sharing we show that due to the strength disorder of fibers, the lifetime ʧ of the bundle has sample-to-sample fluctuations characterized by a log-normal distribution independent of the type of disorder. We determine the Monkman-Grant relation of the model and establish a relation between the rupture life tʄ and the characteristic time tm of the intermediate creep regime of the bundle where the minimum strain rate is reached, making possible reliable estimates of ʧ from short term measurements. Approaching macroscopic failure, the deformation rate has a finite time power law singularity whose exponent is a decreasing function of m. On the microlevel the distribution of waiting times is found to have a power law behavior with m-dependent exponents different below and above the critical load of the bundle. Approaching the critical load from above, the cutoff value of the distributions has a power law divergence whose exponent coincides with the stress exponent of Maxwell elements

Equilibrium of drops on inclined hydrophilic surfaces

Why does not gravity make drops slip down the inclined surfaces, e.g., plant leaves? The current explanation is based on the existence of surface inhomogeneities, which cause a sustaining force that pins the contact line. Following this theory, the drop remains in equilibrium until a critical value of the sustaining force is reached. We propose an alternative analysis, from the point of view of energy balance, for the particular case in which the drop leaves a liquid film behind. The critical angle of the inclined surface at which the drop slips down is predicted. This result does not depend explicitly on surface inhomogeneities, but only on the drop size and surface tensions. There is good agreement with experiments for contact angles below 90° where the formation of the film is expected, whereas for greater contact angles great discrepancies arise

Critical thoughts on computing atom condensed Fukui functions

Different procedures to obtain atom condensed Fukui functions are described. It is shown how the resulting values may differ depending on the exact approach to atom condensed Fukui functions. The condensed Fukui function can be computed using either the fragment of molecular response approach or the response of molecular fragment approach. The two approaches are nonequivalent; only the latter approach corresponds in general with a population difference expression. The Mulliken approach does not depend on the approach taken but has some computational drawbacks. The different resulting expressions are tested for a wide set of molecules. In practice one must make seemingly arbitrary choices about how to compute condensed Fukui functions, which suggests questioning the role of these indicators in conceptual density-functional theory

Critical analysis and extension of the Hirshfeld atoms in molecules

The computational approach to the Hirshfeld [Theor. Chim. Acta 44, 129 (1977)] atom in a molecule is critically investigated, and several difficulties are highlighted. It is shown that these difficulties are mitigated by an alternative, iterative version, of the Hirshfeld partitioning procedure. The iterative scheme ensures that the Hirshfeld definition represents a mathematically proper information entropy, allows the Hirshfeld approach to be used for charged molecules, eliminates arbitrariness in the choice of the promolecule, and increases the magnitudes of the charges. The resulting "Hirshfeld-I charges" correlate well with electrostatic potential derived atomic charges

Discourse, knowledge, power and politics: towards critical epistemic discourse analysis

Although both are fundamental terms in the humanities and social sciences, discourse and knowledge have seldom been explicitly related, and even less so in critical discourse studies. After a brief summary of what we know about these relationships in linguistics, psychology, epistemology and the social sciences, with special emphasis on the role of knowledge in the formation of mental models as a basis for discourse, I examine in more detail how a critical study of discourse and knowledge may be articulated in critical discourse studies. Thus, several areas of critical epistemic discourse analysis are identified, and then applied in a study of Tony Blair’s Iraq speech on March 18, 2003, in which he sought to legitimatize his decision to go to war in Iraq with George Bush. The analysis shows the various modes of how knowledge is managed and manipulated of all levels of discourse of this speech.

Film's frame

A partir de un acto interactivo con la wwww.aeat.es, el usuario envía telemáticamente el modelo 100 en un entorno con tendencia a la incertidumbre y a las dificultades de usabilidad, sin embargo, la investigación pretende demostrar que en dicho acto, el usuario construye una historia narrativa debido a la existencia de una motivación y a la tendencia connatural a la representación narrativa, a pesar que la web no fue intencionalmente construida con propósitos narrativos. El estudio, además, enfoca la interacción como un acto inmersivo y reconoce en la incertidumbre las variables que determinan la continuidad y rumbo del relato. La investigación propone un modelo interpretativo para el análisis y la estructuración del espacio y la historia implícita. Y a nivel exploratorio, se propone la aplicación del Mouse Tracking como técnica científica.

Price regulation of plastic money: A critical assessment of Spanish rules

Recent decisions by the Spanish national competition authority (TDC) mandate paymentsystems to include only two costs when setting their domestic multilateral interchange fees(MIF): a fixed processing cost and a variable cost for the risk of fraud. This artificiallowering of MIFs will not lower consumer prices, because of uncompetitive retailing; but itwill however lead to higher cardholders fees and, likely, new prices for point of saleterminals, delaying the development of the immature Spanish card market. Also, to the extent that increased cardholders fees do not offset the fall in MIFs revenue, the task of issuing new cards will be underpaid relatively to the task of acquiring new merchants, causing an imbalance between the two sides of the networks. Moreover, the pricing scheme arising from the decisions will cause unbundling and underprovision of those services whose costs are excluded. Indeed, the payment guarantee and the free funding period will tend to be removed from the package of services currently provided, to be either provided by third parties, by issuers for a separate fee, or not provided at all, especially to smaller and medium-sized merchants. Transaction services will also suffer the consequences that the TDC precludes pricing them in variable terms.

The three strands of intercultural polities: a comprehensive view. A critical review of Bouchard and Cantle recent books on interculturalism

Within the emerging policy debate on interculturalism we critically review two recent books in 2012: Bouchard’s L’interculturalisme: un point de vue quebecois, and Cantle’s Interculturalism: The New Era of Cohesion and Diversity. In my view, both contribute very directly to open a foundational debate on interculturalism. In addressing the point of convergence and the dividing lines of these two contributions, I will claim that in spite of having one core concept of interculturalism, there are, however, at least two basic conceptions that have to be interpreted in complementary ways: Bouchard’s essay represents the contractual strand, Cantle’s book the cohesion strand. At the end I would also suggest that these two strands do not manage to express explicitly that diversity can also be seen as a resource of innovation and creativity, and so can drive individual and social development. This view is based on the diversity advantage literature already informing most of the diversity debate in Europe and elsewhere. This is what I will call the constructivist strand. My ultimate purpose is to defend a comprehensive view, grounded on the argument that no one can have the sole authority to define intercultural policy, since the three strands can be applied at different moments, according to different purposes and policy needs. The challenge now is that policy managers be able to achieve a balance between these three policy drivers.

States of maximum entropy production in a onedimensional vertical model with convective adjustment

We investigate the hypothesis that the atmosphere is constrained to maximize its entropy production by using a one-dimensional (1-D) vertical model. We prescribe the lapse rate in the convective layer as that of the standard troposphere. The assumption that convection sustains a critical lapse rate was absent in previous studies, which focused on the vertical distribution of climatic variables, since such a convective adjustment reduces the degrees of freedom of the system and may prevent the application of the maximum entropy production (MEP) principle. This is not the case in the radiative–convective model (RCM) developed here, since we accept a discontinuity of temperatures at the surface similar to that adopted in many RCMs. For current conditions, the MEP state gives a difference between the ground temperature and the air temperature at the surface ≈10 K. In comparison, conventional RCMs obtain a discontinuity ≈2 K only. However, the surface boundary layer velocity in the MEP state appears reasonable (≈3 m s-¹). Moreover, although the convective flux at the surface in MEP states is almost uniform in optically thick atmospheres, it reaches a maximum value for an optical thickness similar to current conditions. This additional result may support the maximum convection hypothesis suggested by Paltridge (1978)

Structural and functional characterization of (110)-oriented epitaxial La2/3Ca1/3MnO3 electrodes and SrTiO3 tunnel barriers

La2/3Ca1/3MnO3 (LCMO) films have been deposited on (110)-oriented SrTiO3 (STO) substrates. X-ray diffraction and high-resolution electron microscopy reveal that the (110) LCMO films are epitaxial and anisotropically in-plane strained, with higher relaxation along the [1¿10] direction than along the [001] direction; x-ray absorption spectroscopy data signaled the existence of a single intermediate Mn3+/4+ 3d-state at the film surface. Their magnetic properties are compared to those of (001) LCMO films grown simultaneously on (001) STO substrates It is found that (110) LCMO films present a higher Curie temperature (TC) and a weaker decay of magnetization when approaching TC than their (001) LCMO counterparts. These improved films have been subsequently covered by nanometric STO layers. Conducting atomic-force experiments have shown that STO layers, as thin as 0.8 nm, grown on top of the (110) LCMO electrode, display good insulating properties. We will show that the electric conductance across (110) STO layers, exponentially depending on the barrier thickness, is tunnel-like. The barrier height in STO (110) is found to be similar to that of STO (001). These results show that the (110) LCMO electrodes can be better electrodes than (001) LCMO for magnetic tunnel junctions, and that (110) STO are suitable insulating barriers.

Micro-Raman study of stress distribution in local isolation structures and correlation with transmission electron microscopy

Stress in local isolation structures is studied by micro‐Raman spectroscopy. The results are correlated with predictions of an analytical model for the stress distribution and with cross‐sectional transmission electron microscopy observations. The measurements are performed on structures on which the Si3N4 oxidation mask is still present. The influence of the pitch of the periodic local isolation pattern, consisting of parallel lines, the thickness of the mask, and the length of the bird"s beak on the stress distribution are studied. It is found that compressive stress is present in the Si substrate under the center of the oxidation mask lines, with a magnitude dependent on the width of the lines. Large tensile stress is concentrated under the bird"s beak and is found to increase with decreasing length of the bird"s beak and with increasing thickness of the Si3N4 film.

Fine speckle contrast in InGaAs/InP systems: Influence of layer thickness, missmatch, and growing temperature

This work is focused on the study of the fine speckle contrast present in planar view observations of matched and mismatched InGaAs layers grown by molecular beam epitaxy on InP substrates. Our results provide experimental evidence of the evolution of this fine structure with the mismatch, layer thickness, and growth temperature. The correlation of the influence of all these parameters on the appearance of the contrast modulation points to the development of the fine structure during the growth. Moreover, as growth proceeds, this structure shows a dynamic behavior which depends on the intrinsic layer substrate stress.