97 research outputs found
Origin of steps in magnetization loops of martensitic Ni-Mn-Ga films on MgO(001)
No full textWe study the temperature dependent magnetization properties of (010)-oriented Ni-Mn-Ga epitaxial films on MgO(001) substrates. In the martensitic phase, we observe pronounced abrupt slope changes in the magnetization loops for all studied samples. Our experimental findings are discussed in conjunction with the micromagnetic simulations, revealing that the characteristic magnetization behavior is governed solely by the magnetization switching within the specific martensitic variant pattern, and no reorientation of twin variants is involved in the process. Our study emphasizes the important role of the magnetostatic interactions in the magnetization behavior of magnetic shape memory alloy thin films.publishe
Effects of film thickness and composition on the structure and martensitic transition of epitaxial off-stoichiometric Ni-Mn-Ga magnetic shape memory films
No full textEpitaxial Ni-Mn-Ga magnetic shape memory films with varied thickness and variable stoichiometry were prepared by magnetron sputtering on MgO(001) substrates and investigated by using x-ray diffraction (XRD), scanning tunneling microscopy (STM) and scanning electron microscopy (SEM). The results demonstrate that the structure of the films is either a non-modulated martensite or a seven-layer-modulated martensite. At small film thicknesses, we observe a preferential alignment of the {110} twin planes titled 45 degrees from the substrate surface, which gives rise to the surface corrugation, whereas at large thicknesses, twin planes align additionally along the perpendicular planes. The biaxial tensile stress due to the film-substrate lattice mismatch is shown to have an important role in the selection of the possible twinning planes. An exponential relation between the stress and the film thickness is identified. In contrast, the magnetic properties of the films are found to be independent of the stress. A resistance maximum is measured close to the Curie temperature, which can be attributed to the relaxation of the lattice distortion induced by magnetoelastic coupling.BMBF [13N10060, 13N10061, 13N10062
Microstructure and atomic configuration of the (001)-oriented surface of epitaxial Ni-Mn-Ga thin films
No full textThe (001)-oriented surface of epitaxial off-stoichiometric Ni-Mn-Ga ferromagnetic shape memory alloys was studied in both austenitic and martensitic phases. Scanning tunneling microscopy (STM) imaging of the austenitic surface reveals a well-ordered and reconstruction-free surface exhibiting predominantly Mn-Ga termination. We found that only one of the two atomic species (Ga or Mn) is visible in STM, which is attributed to a pronounced geometric corrugation of the surface layer. After a transformation of the sample from the initial austenitic phase to the martensitic phase upon a high-temperature annealing step, a thorough investigation of the martensitic surface was conducted. On a larger scale, pronounced corrugation lines arise from the macroscopically twinned surface. A second corrugation feature is found on a distinctly smaller scale and is shown to originate from the modulated nature of the martensitic film structure. The irregularly spaced corrugation lines support the model of adaptive martensites.Bundmesministerium fur Bildung und Forschung (BMBF) [13N10061, 13N10062
Raman scattering from layered superconductors: effects of charge ordering, two-band superconductivity, and structural disorder
No full textSubject of this dissertation is the investigation with experimental means of how the Raman response of three structurally similar materials - MgB2, NbSe2, and CaC6- is affected by superconductivity (all three), charge ordering (NbSe2), or crystalline order-to-disorder phase transitions (CaC6). Universal characteristics of spectral renormalization pertaining to the superconducting phase transition are observed in all three compounds. Yet, the crystalline and electronic structures are sufficiently distinct, such that specific for each compound characteristics are imposed on this superconductivity-induced renormalization. Consequently, the method of polarized Raman scattering has been used to establish a variety of physical concepts: 1. Multi-band superconductivity in the layered superconductor MgB2 and its primary mediation by the strongly coupled 640 cm-1 E2g phonon. Additionally, it is shown how a Josephson-like coupling of two SC condensates in the reciprocal space is responsible for an exotic collective mode, the Leggett's resonance. 2. The Interplay between the superconducting and the incommensurate charge-density-wave order parameters in NbSe2, which has been found to be consistent with an isotropic multi-band superconductivity scenario. This scenario is proposed in the frame of a picture that involves a combined "superconductivity plus charge-density-wave" order parameter. 3. The Fano-Breit-Wigner line-shape formalism to account for an anti-resonance interference in the low temperature Raman response from NbSe2 in the polarization geometry corresponding to the non-symmetric E2g symmetry channel. 4. Validity of the double resonant Raman scattering picture in the presence of disorder in the graphite intercalation compound CaC6. Simultaneously, it is explored how disorder suppresses superconductivity. To that end, the CaC6 superconducting coherence peak, too, is presented. All these phenomena are manifestations of electron-phonon coupling in solids. It is probed by inelastic light scattering under the specific constraints of respective crystalline symmetries. Each case, therefore, remains intriguingly unique. The experiments have been performed in a state of the art optical laboratory with low temperatures and high magnetic fields infrastructure, of which a detailed account is given.Ph.D.Includes bibliographical referencesIncludes vitaby Aleksej Mialitsi
Heurs et malheurs des langues finno-ougriennes de Russie
Get PDFDans cet essai, l’auteur exprime quelques idées sur les processus externes et internes en cours dans les langues finno-ougriennes de Russie en ce début de xxe siècle. Il se penche sur certains phénomènes réguliers qui caractérisent la situation des langues minoritaires et permettent d’apprécier la mosaïque du monde finno-ougrien par le prisme de l’intuition philologique. Chercheur et poète, Aleksej Arzamazov met ici en évidence, sans se borner à une stricte interprétation scientifique, quelques satisfactions et quelques souffrances que suscite la situation actuelle de l’oudmourte et discute des possibilités et des perspectives des projets de langues artificielles.В эссе отражены некоторые мысли о внешних и внутренних процессах, имеющих место в финно-угорских языках России в начале XXI столетия. Автор останавливается на отдельных неочевидных закономерностях и состояниях миноритарных языков, позволяющих посмотреть на мозаику финно-угорского мира сквозь призму филологической интуиции. Оставляя в стороне строго-научные методы интерпретации, филолог и поэт Алексей Арзамазов очерчивает круг радостей и страданий удмуртского языка и рассуждает о возможностях и перспективах искусственных языковых проектов.This essay reflects the author’s thoughts about the external and internal processes that are taking place in the Finno-Ugric languages in Russia at the beginning of the 21st century. The author concentrates on some non- visible regularities and peculiarities of minority language, which allow looking at the Finno-Ugric world’s mosaic from the point of view of philological intuition. Aleksej Arzamazov is both poet and scholar. Here, he leaves apart rigid scientific interpretation methods and emphasises some rejoicing and saddening features in the Udmurt experience; he reflects as well on the possibilities and perspectives of artificial language projects
Structural and electronic properties of Ni-Mn-Ga magnetic shape memory alloys
No full textIn recent years there has been an increased demand for the development of smart and functional materials for integration into actuators, sensors and energy harvesting devices. Magnetic shape memory alloys represent a new type of multifunctional materials, which display a strong coupling between structural and magnetic degrees of freedom, accompanied by a strong magnetocrystalline anisotropy. Thus, exposed to sufficiently high magnetic fields, they show a macroscopic shape change. The effect arises from the reversible rearrangement of the martensitic microstructure. To date, Ni-Mn-Ga based alloys have demonstrated many remarkable properties, like 10% magnetic field induced strain and operating frequencies up to the lower kHz range, thus being of particular technological interest. In order to perform their rational design, the microscopic origin of their functional properties must be understood.Since the discovery of the magnetic shape memory effect in Ni-Mn-Ga a strong effort has been first of all invested into improvement of the performance of bulk materials. However, the fundamental microscopic properties of these multifunctional materials were not intensively investigated from the experimental point of view. This thesis is devoted to the implementation of surface sensitive techniques for the investigation of structural and electronic properties of Ni-Mn-Ga magnetic shape memory alloys. There is also an emphasis on the fabrication of freestanding Ni-Mn-Ga thin film microstructures, relevant for device applications.A fabrication process was developed to prepare freestanding single crystalline Ni-Mn-Ga film microstructures. This process is based on electron beam lithography, focused ion beam milling and wet chemical etching. A thermally induced change of the martensitic twin variant configuration was observed.Temperature dependent scanning tunneling microscopy was used to investigate the surface structure of Ni-Mn-Ga alloys in both austenitic and martensitic phases. Film samples epitaxially grown on MgO(001) substrates and single crystal samples were studied. The microscopic surface structure was addressed from the micrometer scale down to the atomic level. Measurements revealed a well-ordered surface exhibiting a Mn-Ga termination. In the martensitic phase a distinct surface corrugation feature originating from the modulated nature of martensite was observed. Topography measurements demonstrate that martensitic Ni-Mn-Ga exhibits two distinctly different martensitic phases with respect to the nature of the modulation. On the one hand, sinusoidal modulation with incommensurate five-fold period was found for stoichiometric alloys. The periodic lattice distortion is accompanied by a charge density wave. On the other hand, a nearly seven-fold nanotwinned configuration with random stacking faults was identified for alloys with off-stoichiometric compositions. The structural modulation appears to be similar to the hierarchical microstructure predicted by the concept of adaptive martensite.Electronic properties of the stoichiometric Ni2MnGa compound have been studied by means of angle-resolved photoemission spectroscopy. Fermi surface topology has been examined in the austenitic state. A nesting feature, which has been previously identified in theoretical calculations, has been observed. The nesting vector matches the modulation period of the martensitic structure. Spectra, obtained in the martensitic state, provide a convincing proof of the a pseudogap formation for the nested parts of the Fermi surface. These results are in line with the observation of a charge density modulation by STM and support the assumption of a Peierls like instability. Temperature dependent ultraviolet photoemission spectra demonstrate a similar transfer of spectral weight near the Fermi level across the martensitic transformation for off-stoichiometric and stoichiometric alloys.It can be consistently accounted for the seemingly conflicting observations of two different Ni-Mn-Ga martensitic microstructures if a strong electron-lattice coupling scenario is considered.publishe
Проблемы русскоязычного населения в постсоветских государствах
No full textвыпускная квалификационная работа посвящена проблемам русскоязычного населения на постсоветском пространстве. В работе рассмотрен временной период 1989-2019 год. Приводятся данные о различных параметрах, влияющих на положение русскоязычного населения в странах бывшего СССР. Выделяемая категория, охватывает не только этнических русских, но и других жителей постсоветских государств, которые использую русский язык. Русскому языку, как ключевому критерию функционирования русскоязычной общины уделяется особое внимание. Оценивается динамика его использования, и на основе выделенных автором показателей создается бальная система оценок. Полученные результаты отражаются на картосхеме. В работе также оценивается геополитические интересы России в регионах, где проживает русскоязычное население, и делается прогноз о влиянии политики на русскоговорящих людей. Содержание выпускной квалификационной работы изложено на 98 страницах печатного текста, который включает введение, 4 главы, заключение, список литературы, 1 приложение, 20 таблиц и 6 графиков и рисунковthe final qualifying work is devoted to the problems of the Russian-speaking population in the post-Soviet space. The author considers the time period 1989-2019 year. The data on various parameters affecting the position of the Russian-speaking population in the countries of the former USSR are given. The selected category covers not only ethnic Russians, but also other residents of post-Soviet states who use Russian. The Russian language as a key criterion for the functioning of the Russian-speaking community is given special attention. The dynamics of its use are assessed, and a score system is created on the basis of the indicators selected by the author. The results obtained are reflected in the circuit map. The work also assesses the geopolitical interests of Russia in the regions where the Russian-speaking population lives, and makes a forecast about the influence of politics on Russian-speaking people. The content of the final qualifying work is presented on 98 pages of printed text, which includes an introduction, 4 chapters, conclusion, list of references, 1 annex, 20 tables and 6 graphs and figure
"Per una mappatura della Russia contemporanea". Aleksej Ivanov, il geografo si è bevuto il globo. Proposta di traduzione editoriale.
No full textThe purpose of this work is to introduce to the Italian audience one of the best known works written by the Russian novelist Aleksej Ivanov. The title of the book we refer to is Geograf glubus propil, [The geography drank his globe away]. The novel features peculiarities and themes that can be interesting also for non-Russian readers, being also an example of how Russian contemporary literature has evolved through the years. Nevertheless, it has already been translated in French and Serbian.
In last years, the author has become increasingly famous in Russia: he has won many prices and has published a large number of books, many of which were awarded with different literature prizes.
Moreover, a film based on the plot of the novel analyzed has been released in 2013, carrying the same name of the book. The film received positive feedback from both cinema critics and mass audience.
The following work has been divided into two parts: an introductory part where the author and his book are presented, together with the main character and his peculiarities. It is then explained the context in which the book was created, the purpose of the author and how the book was perceived by readers.
In addition to that, I listed some of the problems I had to face while translating , and the solutions I found in order to solve them. The second part is fully dedicated to the translation itself
Traduire sous la contrainte: la traduction et la numérisation de la poésie
No full textThe thesis addresses the translation and digitization of 1910s-1920s Russian poetry known as “zaum poetry”. The first chapter is a study of Russian zaum poetry from Velimir Hlebnikov, Aleksej Kručënyh and Il’â Zdanevič. The second chapter is an analysis of the reception of zaum poetry in Paris during the 1920s and during the after-war period. The third part is a critical and theoretical study of the problems of translating zaum poetry towards English and French. It includes studies of translations of zaum poetry by Jean-Claude Lanne, Allison Pultz and Gerald Janecek, André Markowicz, Régis Gayraud and Yvan Mignot. The fourth chapter is an analysis of translations of poems from Aleksej Kručënyh and Il’â Zdanevič by the author, as well as an analysis of their digital remediation by the author.Ph. D.Includes bibliographical referencesIncludes vitaby Jonathan Baillehach
Il Canzoniere di Petrarca : nella traduzione di Aleksej Berdnikov
No full textA una breve premessa sulla fortuna del Petrarca in Russia segue, nell’articolo, una rapida panoramica delle traduzioni disponibili nel contesto editoriale russo nei primi due decenni degli anni Duemila. Il contributo si sofferma sulla traduzione del Canzoniere di Petrarca di Aleksej Berdnikov, pubblicata nel 2017. Nonostante il talento del traduttore e la sua padronanza delle tecniche poetiche, essa ha suscitato scarso in-teresse sia nel pubblico sia nella critica. La traduzione di Berdnikov, realizzata per la maggior parte a metà degli anni Ottanta del XX secolo come esempio di letteratura underground, si basa sulla lingua del tardo periodo sovietico con i suoi diversi registri stilistici stratificati e riferimenti culturali. Interpretato con ironia postmodernista e con spirito ludico, il Petrarca di Berdnikov al lettore contemporaneo appare bizzarro e per molti aspetti forse addirittura inconcepibile, o quanto meno assai diverso dal Petrarca conosciuto nel periodo sovietico. Sperimentando un inedito approccio alla traduzione dei classici, Berdnikov pone in risalto la dipendenza del testo dalle accezioni culturali e linguistiche proprie di un determinato periodo e la breve durata della traduzione nel tempo.
After a brief introduction tracking Petrarch’s fortune in Russia, the author describes the situation in the two thousand and focuses on the translation of Petrarch’s Canzoniere made by Aleksey Berdnikov and published in 2017 to explain why, in spite of translator’s talent and masterful command in poetical techniques, it passed without public and critical interest. Berdnikov’s translation, being mostly realized in the mid of the 1980-s as a piece of underground literature, is based on the language of the late soviet period with its different stylistic strata and cultural references. Interpreted with postmodernist irony and a certain ludic spirit, Berdnikov’s Petrarch looks odd and in many aspects inconceivable to the modern reader who is different from that of the soviet period. As a possible way of translating classics, Berdnikov’s experience showed its dependency on the cultural and linguistic nuances of a certain period and its historical shortness
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