Magnetophotoresistance in Pr 1–x CaxMnO3 Thin Films

In this work, a colossal magnetoresistive (CMR) Pr1−xCaxMnO3 (PCMO) man- ganite thin films and polycrystalline samples were studied with the main focus on the properties of the insulator to metal Mott phase transition. The polycrystalline PCMO samples were fabricated with the solid state reaction method. The polycrystalline sam- ples were further processed into the epitaxial thin films with the pulsed laser deposition method (PLD). The structural and magnetic properties of the samples were systemat- ically investigated and the thin films samples were further investigated with magneto- transport measurement where the thin films response to illumination was also studied. After the successful synthesis of polycrystalline PCMO samples with varying x = between 0.0 - 0.5, the magnetic characterization of the samples showed rich magnetic properties having the signatures of the magnetic phase coexistence of antiferromag- netic (AFM) and ferromagnetic (FM) ordering and cluster glass behaviour. With the increased doping concentration from x = 0.3 to 0.5, the AFM charge-order (CO) phase started to form up being strongest on the sample x = 0.5. This AFM CO phase could be melted with the high external magnetic field at temperatures below Neel’s tempera- ture TN inducing an irreversible first order metamagnetic AFM to FM phase transition. The strength of the AFM CO phase decreased with decreasing Ca concentration and increasing temperature. The polycrystalline PCMO samples with Ca concentrations of 0.3 - 0.5, showing metamagnetic behaviour, were selected for the fabrication of the thin film samples. The films were grown using two different in situ oxygen treatment temperatures at 500 ◦C and 700 ◦C in the PLD system. The films with x = 0.4 and 0.5 showed weaker AFM CO phase with greatly reduced melting fields when compared to polycrystalline samples. Also, the robustness of the AFM CO phase was further decreased in thin films with the lower oxygen treatment temperature of 500 ◦C. The magneto-transport measurements made on the thin films showed that the melting of AFM CO phase was connected to CMR effect where the increasing magnetic field induced an insulator to metal phase transition, which reduces the resistivity of the film around nine orders of magnitude. The use of illumination during the magneto-transport measurements showed a vari- ety of intriguing phenomena including magnetophotoresistance. The illumination had a huge effect to the insulator to metal transition (IMT) reducing the transition magnetic field significantly. Moreover, by magnetically biasing the thin films with the constant external magnetic field, the IMT could be induced by switching on the illumination.

Resilience and the cultural landscape : the case of the Lower Ninth Ward after Hurricane Katrina

Le but de cette recherche est d’évaluer l’importance du paysage culturel dans la résilience des communautés urbaines post-catastrophes. Ce travail se concentre sur le quartier du Lower Ninth Ward dans la ville de La Nouvelle-Orléans (États-Unis) après le passage de l’ouragan Katrina en 2005. Les catastrophes naturelles prennent une envergure et causent des dommages considérables lorsqu’elles touchent des villes. La reconstruction post -désastre est donc très dispendieuse pour les villes et les gouvernements, d’autant que certaines régions sont dévastées au point qu’elles doivent être reconstruites au complet. Cependant, le coût le plus lourd à assumer reste celui en vies humaines et si rebâtir les éléments concrets d’une ville est une tâche difficile à entreprendre, reconstruire une communauté est considérablement plus complexe. Dans le but de comprendre une telle démarche, cette recherche se concentre sur les éléments intangibles, comme l’attachement au lieu et les réseaux sociaux, dont une communauté a besoin pour se reconstituer de façon durable et résiliente. Le concept de résilience est très contesté dans la littérature et plusieurs chercheurs se sont essayés à le mesurer. Cette recherche adopte une perspective critique sur le concept et le revisite d’un point de vue holistique pour mettre en lumière sa complexité. Cette démarche permet de remettre en question l’importance de mesurer un concept finalement en perpétuelle redéfinition dans le temps et selon les échelles géographiques. De plus, en établissant une relation entre résilience et paysage culturel, il a été possible de mieux comprendre la complexité de la résilience. Touchant à plusieurs disciplines (architecture de paysage, urbanisme et sociologie), cette recherche utilise une méthodologie qui reflète son aspect multidisciplinaire : les méthodes mixtes. Ces dernières permettent la collecte de données quantitatives et qualitatives qui produisent une vue globale de la situation post-Katrina à travers le regroupement de recensions statistiques, d’observations de terrain et d’articles de journaux. Parallèlement, des entretiens ont été réalisés avec des résidents du quartier ainsi qu’avec des professionnels pour mieux comprendre les différents points de vue. Cette méthodologie a permis de produire des résultats au niveau du cas d’étude autant qu’au niveau théorique. La recherche valide l’importance de prendre en compte le paysage culturel dans les situations post-catastrophes, (en particulier) dans la mesure où il s’agit d’un élément souvent négligé par les urbanistes et les acteurs locaux. En effet, les éléments constitutifs du paysage culturel tels que l’attachement au lieu et les réseaux sociaux, participent d’un sentiment d'appartenance (« home ») et d’une volonté, pour les résidents, de reconstruire leurs habitations, leur communauté ainsi que leur quartier. Toutefois, il faut reconnaître que ces éléments ne suffisent pas à retrouver ce qu’ils ont perdu. Ainsi, l’étude du paysage culturel permet non seulement de mieux comprendre la complexité de la résilience, mais démontre également que cette dernière est une construction sociale.

Lessons from natural disasters, tsunami-affected Small and Medium-Sized Enterprises(SMEs) in Sri Lanka

The main objective of this paper is to identify some of the key issues encountered by tsunami-affected small and medium-sized enterprises (SMEs) in the process of rehabilitation and re-establishment in Sri Lanka. The second objective is to assess how far these affected industries have received various benefits and supports from bodies such as government agencies, private sector firms, donors and NGOs to help them get back into business. The final objective is to recommend policies and strategies to develop the tsunami-affected SMEs in a self-sustaining manner and within a certain time period. The main database of firms for this research has been obtained from the Industrial Development Board, which conducted a survey covering 4,389 tsunami-affected micro- and SMEs. In addition to this, information from various state organizations and NGOs-based sources has been used. This paper identifies the main issues related to tsunami-affected SMEs ranging from basic infrastructure provision up to finance, marketing, machinery, technology, training, product identification and development and so forth. In fact, it is shown that there are no significant differences between issues faced by SMEs in general and tsunami-affected SMEs, apart of course from the effects of a sudden disaster (the tidal wave). Consequently, these issues can be generalized as issues relevant to SMEs in Sri Lanka as a whole. However, under the flood and rain of local and foreign assistance, there have been more pledges and promises than actual deliveries and, so, tsunami-affected SMEs have received comparatively little support and assistance in recovering and no records can be found as to where the colossal amount of foreign assistance received has actually gone. Finally, this paper recommends various types of business incubator centres and entrepreneurial enhancing skill programmes for the revamping of tsunami-affected SMEs in addition to the normal disaster risk management plan.

A literary approach to teaching english language in a multicultural classroom

Literature is not generally considered as a coherent branch of the curriculum in relation to language development in either native or foreign language teaching. As teachers of English in multicultural Indian classrooms, we come across students with varying degrees of competence in English language learning. Although language learning is a natural process for natives, students of other languages put in colossal efforts to learn it. Despite their sincere efforts, they face challenges regarding pronunciation, spelling, and vocabulary. Indian classrooms are a microcosm of the larger society, so teaching English language in a manner that equips the students to face the cutthroat competition has become a necessity and a challenge for English language teachers. English today has become the key determinant for being successful in their careers. The hackneyed and stereotypical methods of teaching are not acceptable now. Teachers are no longer arbitrary dispensers of knowledge, but they are playing the role of a guide and facilitator for the students. Teachers of English are using innovative ideas to make English language teaching and learning interesting and simple. Teachers have started using literary texts and their analyses to explore and ignite the imagination and creative skills of the students. One needs to think and rethink the contribution of literature to intelligent thinking as well as its role in the process of teaching/learning. This article is, therefore, an attempt at exploring the nature of the literary experience in the present-day classrooms and the broader role of literature in life.

How do Firms ask for Consumers’ Data Permission? The Value of Companies Data Practices.

On May 25, 2018, the EU introduced the General Data Protection Regulation (GDPR) that offers EU citizens a shelter for their personal information by requesting companies to explain how people’s information is used clearly. To comply with the new law, European and non-European companies interacting with EU citizens undertook a massive data re-permission-request campaign. However, if on the one side the EU Regulator was particularly specific in defining the conditions to get customers’ data access, on the other side, it did not specify how the communication between firms and consumers should be designed. This has left firms free to develop their re-permission emails as they liked, plausibly coupling the informative nature of these privacy-related communications with other persuasive techniques to maximize data disclosure. Consequently, we took advantage of this colossal wave of simultaneous requests to provide insights into two issues. Firstly, we investigate how companies across industries and countries chose to frame their requests. Secondly, we investigate which are the factors that influenced the selection of alternative re-permission formats. In order to achieve these goals, we examine the content of a sample of 1506 re-permission emails sent by 1396 firms worldwide, and we identify the dominant “themes” characterizing these emails. We then relate these themes to both the expected benefits firms may derive from data usage and the possible risks they may experience from not being completely compliant to the spirit of the law. Our results show that: (1) most firms enriched their re-permission messages with persuasive arguments aiming at increasing consumers’ likelihood of relinquishing their data; (2) the use of persuasion is the outcome of a difficult tradeoff between costs and benefits; (3) most companies acted in their self-interest and “gamed the system”. Our results have important implications for policymakers, managers, and customers of the online sector.

Fabrication and characterization of hybrid ferromagnetic-organic heterostructures for spintronics application

Recent research in the field of organic spintronics highlighted the peculiar spin-dependent properties of the interface formed by an organic semiconductor (OSC) chemisorbed over a 3d ferromagnetic metal, also known as spinterface. The hybridization between the molecular and metallic orbitals, typically π orbitals of the molecule and the d orbitals of the ferromagnet, give rise to spin dependent properties that were not expected by considering the single components of interfaces, as for example the appearance of a magnetic moment on non-magnetic molecules or changes in the magnetic behavior of the ferromagnet. From a technological viewpoint these aspects provide novel engineering schemes for spin memory and for spintronics devices, featuring unexpected interfacial magnetoresistance, spin-filtering effects and even modulated magnetic anisotropy. Applications of these concepts to devices require nevertheless to transfer the spinterface effects from an ideal interface to room temperature operating thin films. In this view, my work presents for the first time how spinterface effects can be obtained even at room temperature on polycrystalline ferromagnetic Co thin films interfaced with organic molecules. The considered molecules were commercial and widely used in the field of organic electronics: Fullerene (C60), Gallium Quinoline (Gaq3) and Sexithiophene (T6). An increase of coercivity, up to 100% at room temperature, has been obtained on the Co ultra-thin films by the deposition of an organic molecule. This effect is accompanied by a change of in-plane anisotropy that is molecule-dependent. Moreover the Spinterface effect is not limited to the interfacial layer, but it extends throughout the whole thickness of the ferromagnetic layer, posing new questions on the nature of the 3d metal-molecule interaction.