Bibliografie tematiche / Polarisation du spin

Letteratura scientifica selezionata sul tema "Polarisation du spin"

Autore: Grafiati

Pubblicato: 8 giugno 2024

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Articoli di riviste sul tema "Polarisation du spin":

Lohmann, B. "Recent Developments of Resonant Auger Transitions: Predictions and Propensity Rules for the Dynamic Spin Polarisation". Australian Journal of Physics 52, n. 3 (1999): 397. http://dx.doi.org/10.1071/ph99019.

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The angular distribution and spin polarisation of the resonantly photoexcited Xe¤(4d–15/2 6p3/2 ) N5O2,3O2,3 Auger spectrum is investigated. The two-step model has been used which allows us to independently determine the dynamic parameters of the primary excitation and the Auger emission process. Assuming either a fully circularly or linearly polarised photon beam the dynamic parameters determining the primary photoexcitation become constant numbers independent of the matrix elements. Applying a relativistic distorted wave approximation the relevant numbers describing the Auger decay dynamics, i.e. relative intensities, angular distribution and spin polarisation parameters have been calculated, and are compared with experimental and other theoretical data. With this, predictions for the spin polarisation vector are possible. A large degree of dynamic spin polarisation has been found for all Auger transitions to a final state with Jf = ½ . This is in contrast to earlier calculations for diagram Auger transitions. Recently, we have given an explanation for this deriving propensity rules for resonant Auger transitions. The propensity rules allow for predictions for which Auger line a large dynamic spin polarisation can be expected. The predictions are in accord with our multiconfigurational Dirac–Fock calculations for the resonant Xe N5O2,3O2,3 and Ar L3M2,3M2,3 Auger multiplets. It is demonstrated that the effect of a large spin polarisation is caused by a large shift of the scattering phase of the emitted ?s1/2 partial waves, whereas a small spin polarisation is due to a cancellation between the Coulomb and scattering phases of the partial waves.

Stephen, P. Clough, J. Eberle William e Gilbert Gillman. "L'analyse de polarisation de spin :". Matériaux & Techniques 77, n. 3 (1989): 33–34. http://dx.doi.org/10.1051/mattech/198977030033.

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Schulz, H. J. "Spin-polarisation effects in luminescence". Journal of Luminescence 48-49 (gennaio 1991): 675–79. http://dx.doi.org/10.1016/0022-2313(91)90217-j.

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McEwen, Jason D., Martin Büttner, Boris Leistedt, Hiranya V. Peiris, Pierre Vandergheynst e Yves Wiaux. "On spin scale-discretised wavelets on the sphere for the analysis of CMB polarisation". Proceedings of the International Astronomical Union 10, S306 (maggio 2014): 64–67. http://dx.doi.org/10.1017/s1743921314011107.

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AbstractA new spin wavelet transform on the sphere is proposed to analyse the polarisation of the cosmic microwave background (CMB), a spin ± 2 signal observed on the celestial sphere. The scalar directional scale-discretised wavelet transform on the sphere is extended to analyse signals of arbitrary spin. The resulting spin scale-discretised wavelet transform probes the directional intensity of spin signals. A procedure is presented using this new spin wavelet transform to recover E- and B-mode signals from partial-sky observations of CMB polarisation.

Kaur, Nimardeep, Rupinder Kaur e N. S. Saini. "Ion-Acoustic Cnoidal Waves with the Density Effect of Spin-up and Spin-down Degenerate Electrons in a Dense Astrophysical Plasma". Zeitschrift für Naturforschung A 75, n. 2 (25 febbraio 2020): 103–11. http://dx.doi.org/10.1515/zna-2019-0140.

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AbstractAn investigation of nonlinear ion acoustic (IA) cnoidal waves in a magnetised quantum plasma is presented by using spin evolution quantum hydrodynamics model, in which inertial classical ions and degenerate inertialess electrons with both spin-up and spin-down states taken as separate species are considered. The Korteweg–de Vries equation is derived using the reductive perturbation method. Further, using the Sagdeev pseudopotential approach, the solution for IA cnoidal waves is derived with suitable boundary conditions. There is the formation of only positive potential cnoidal, and in the limiting case, positive solitary waves are observed. The effects of density polarisation and other plasma parameters on the characteristic features of cnoidal and solitary waves have been analysed numerically. It is seen that the spin density polarisation significantly affects the characteristics of cnoidal structures as we move from strongly spin-polarised (μ = 1) to a zero spin-polarisation case (μ = 0). The results obtained in the present investigation may be useful in comprehending various nonlinear excitations in dense astrophysical regions, such as white dwarfs, neutron stars, and so on.

Lee, Wai Tung, Joel Hagman, Damian Martin Rodriguez, Annika Stellhorn, Alex Backs, Thomas Arnold, Elizabeth Blackburn et al. "Polarisation Development at the European Spallation Source". EPJ Web of Conferences 286 (2023): 03004. http://dx.doi.org/10.1051/epjconf/202328603004.

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To meet the ever-increasing user demand, eleven of the fifteen European Spallation Source (ESS) instruments under construction aim to offer polarised neutrons for user experiments. They include an imaging instrument, a SANS instruments, two reflectometers, three diffractometers, and four spectrometers. In conjunction with in-kind contributions and instrumentation grants, the ESS Polarisation Project will support the incorporation of polarisation analysis on eight of the eleven instruments. The project aims to deliver polarised neutrons for first-science experiments as instruments enter operation. Different polariser and polarisation analyser techniques will be available to accommodate the specifics of experiments on a given instrument. Polarised 3He neutron spin filter using either Metastable Optical Pumping (MEOP) or Spin-Exchange Optical Pumping (SEOP) techniques will provide shared-use equipment among many instruments, with SEOP’s main application being in situ beam-polarisation. Several instruments will also use polarising-supermirror devices. To provide wide-bandwidth spin-flipping capability to the time-of-flight instruments, Adiabatic Fast Passage (AFP) neutron spin flippers, also known as gradient-field radiofrequency spin flippers will be the main method of choice. Devices based on the same AFP principle will also be used to flip 3He nuclear spins. We are constructing our first 3He polariser setup, including field coils to produce highly uniform magnetic field. Monte Carlo simulations are being done for the supermirror polarisers. To ensure science-focused development, we are working with university partners in doing scientific experiments with polarised neutrons. These are some of the activities developing polarisation analysis for ESS instruments in our project.

Schattschneider, P., V. Grillo e D. Aubry. "Spin polarisation with electron Bessel beams". Ultramicroscopy 176 (maggio 2017): 188–93. http://dx.doi.org/10.1016/j.ultramic.2016.11.029.

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Carrón Duque, J., A. Carones, D. Marinucci, M. Migliaccio e N. Vittorio. "Minkowski Functionals in 𝖲𝖮(3) for the spin-2 CMB polarisation field". Journal of Cosmology and Astroparticle Physics 2024, n. 01 (1 gennaio 2024): 039. http://dx.doi.org/10.1088/1475-7516/2024/01/039.

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Abstract The study of the angular power spectrum of Cosmic Microwave Background (CMB) anisotropies, both in intensity and in polarisation, has led to the tightest constraints on cosmological parameters. However, this statistical quantity is not sensitive to any deviation from Gaussianity and statistical isotropy in the CMB data. Minkowski Functionals (MFs) have been adopted as one of the most powerful statistical tools to study such deviations, since they characterise the topology and geometry of the field of interest. In this paper, we extend the application of MFs to CMB polarisation data by introducing a new formalism, where we lift the spin 2 polarisation field to a scalar function in a higher-dimensional manifold: the group of rotations of the sphere, SO(3). Such a function is defined as f = Q cos(2ζ) - U sin(2ζ). We analytically obtain the expected values for the MFs of f in the case of Gaussian isotropic polarisation maps. Furthermore, we present a new pipeline which estimates these MFs from input HEALPix polarisation maps. We apply it to CMB simulations in order to validate the theoretical results and the methodology. The pipeline is to be included in the publicly available Python package Pynkowski .

Battiato, M. "Spin polarisation of ultrashort spin current pulses injected in semiconductors". Journal of Physics: Condensed Matter 29, n. 17 (27 marzo 2017): 174001. http://dx.doi.org/10.1088/1361-648x/aa62de.

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McWilliam, Amy, Claire Marie Cisowski, Robert Bennett e Sonja Franke-Arnold. "Angular momentum redirection phase of vector beams in a non-planar geometry". Nanophotonics 11, n. 4 (15 novembre 2021): 727–36. http://dx.doi.org/10.1515/nanoph-2021-0528.

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Abstract An electric field propagating along a non-planar path can acquire geometric phases. Previously, geometric phases have been linked to spin redirection and independently to spatial mode transformation, resulting in the rotation of polarisation and intensity profiles, respectively. We investigate the non-planar propagation of scalar and vector light fields and demonstrate that polarisation and intensity profiles rotate by the same angle. The geometric phase acquired is proportional to j = ℓ + σ, where ℓ is the topological charge and σ is the helicity. Radial and azimuthally polarised beams with j = 0 are eigenmodes of the system and are not affected by the geometric path. The effects considered here are relevant for systems relying on photonic spin Hall effects, polarisation and vector microscopy, as well as topological optics in communication systems.

Più fonti

Tesi sul tema "Polarisation du spin":

Joly, Alexandre. "Optimisation du transfert du spin électronique à la polarisation d’un laser à semi-conducteur à émission par la surface". Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S084/document.

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Dans le cadre de cette thèse, nous présentons l’optimisation du transfert du spin électronique à la polarisation d’un laser à semi-conducteur (SC) à émission par la surface en cavité externe (VECSEL). Un spin-laser pourrait constituer une rupture technologique dans le domaine des communications en répondant à l’augmentation du débit de données tout en apportant des fonctionnalités supplémentaires (cryptage de l’information…). Afin de développer un tel composant, deux approches complémentaires ont été explorées. La première a pour objectif d’appréhender les effets d’injection de spin dans un VECSEL, ainsi que comprendre les paramètres du laser, tels que la biréfringence de phase et le dichroïsme de gain linéaires, qui figent la polarisation à un état linéaire. En réduisant le dichroïsme d’un facteur 50 et en compensant la biréfringence résiduelle de la cavité jusqu’à 0,1 mrad (soit une diminution d’un facteur 40), une augmentation de l’ellipticité de 1° à 35° a été rendue possible. L’injection de porteurs polarisés en spin par pompage optique dans le milieu actif du laser compensé a permis d’obtenir un basculement de l’état de polarisation entre deux états elliptiques ( 35 ↔ +35°). La seconde approche concerne l’étude de l’injection de spin par pompage électrique, point clé du développement d’un dispositif compact. Pour cela, un injecteur ferromagnétique répondant aux contraintes du transport du spin électronique de l’électron vers le SC est inséré dans la cavité optique. Malgré l’utilisation d’une structure anti-résonante, qui permet de limiter l’absorption de l’injecteur intra-cavité, nous démontrons des effets d’électroluminescence dont le profil spatial est compatible avec une émission laser. Enfin, nous apportons les éléments permettant d’améliorer le procédé de fabrication du spin-laser dans l’optique d’obtenir un effet laser
Optimisation of the spin transport to the polarization of a vertical cavity semiconductor laser

Naylor, Adam David. "Measuring spin polarisation with point-contact Andreev reflection". Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534829.

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Eustace, David Andrew. "Spin polarisation effects in electron energy loss spectroscopy". Thesis, University of Glasgow, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438978.

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Tati, Bismaths Logane. "Étude du mouvement du spin d’électrons dans les puits quantiques dépendant du spin". Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/public/theses_doctorat/2008/TATI_BISMATHS_Logane_2008.pdf.

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J’ai étudié dans la première partie de ma thèse le mouvement du spin des électrons réfléchis dans un puits quantique formé par le système Au/Co(001). La présence d’une interface magnétique et l’existence des interférences quantiques entrainent un comportement oscillatoire des angles du mouvement de spin. J’ai aussi montré que ces oscillations peuvent bien être décrites par le modèle d’interféromètre de Fabry-Pérot, et que la simulation des données expérimentales permet l’étude des propriétés de réflexion de l’interface qui ne sont pas accessibles expérimentalement de façon directe. Dans la seconde partie j’ai réalisé une étude similaire sur le système Fe/Ag(001). Deux périodes d’oscillations ont été identifiées : une longue période qui est liées aux effets des interférences quantiques des électrons dans la couche de Fe et une courte période d’une monocouche indépendante de l’énergie des électrons incidents, que avons attribuée à la variation périodique de la morphologie du film de Fe qui alterne entre une couche d’atomes complète et incomplète
In the first part of my PhD I studied the spin-motion of spin-polarized electrons in the quantum well system Au/Co(001). The existence of a ferromagnetic interface and of quantum interferences leads to an oscillatory behaviour of the spin-motion angles. I also showed that these oscillations are well described by a Fabry-Perot interferometer model, and that the simulation of the experimental data allows the study of the spin-dependent reflection properties of the buried interface which are not directly accessible. In the second part, I performed a similar study of the system Fe/Ag(001). Two periods of oscillations were identified in this case: a long one due to quantum interference of electrons in the Fe films, and a short one with the period of one monolayer, which are attribute to the periodic variation of the morphology of the Fe film, alterning between filled and incompletely filled atomic layers

Kaladzhyan, Vardan. "Spin polarisation and topological properties of Yu-Shiba-Rusinov states". Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC215/document.

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Dans ce manuscrit de thèse, nous revisitons d'abord la physique des états de Yu-Shiba-Rusinov, en nous concentrant sur leur polarisation en spin. Nous commençons par montrer théoriquement que nous pouvons extraire beaucoup d'informations sur le supraconducteur hôte, en analysant la densité locale d'états électroniques liée à la présence d'impuretés magnétiques. Tout d'abord, nous démontrons que le couplage spin-orbite peut être lu directement et sans ambiguïté par la spectroscopie par effet tunnel résolu en spin dans les systèmes bidimensionnels et unidimensionnels, qu’ils soient supraconducteurs ou métalliques. Nous analysons les oscillations induites par les impuretés dans la densité d'états électroniques. En particulier, nous nous concentrons sur la transformation de Fourier (TF) des oscillations de Friedel et nous notons que les caractéristiques à haute intensité apparaissent pour un vecteur d'onde donné par deux fois la longueur inverse du spin-orbite. Ensuite, nous montrons qu'il est possible de déterminer le mécanisme d’appariement dominant, qu’il soit en ondes s ou en ondes p, dans les supraconducteurs non conventionnels en analysant la structure spectrale résolue en spin des états liés de Yu-Shiba-Rusinov. De manière frappante, nous démontrons qu'une analyse minutieuse de la densité d'états électroniques polarisée en spin ne permet pas seulement de caractériser sans équivoque le degré d’appariement de type triplet, mais également son orientation, a.k.a. le vecteur d. Enfin, nous proposons et discutons deux approches différentes d'ingénierie et de contrôle des phases topologiques à l’aide d’impuretés scalaires et magnétiques. Nous commençons par fournir une théorie microscopique des réseaux d'impuretés scalaires sur les supraconducteurs chiraux. Nous montrons que pour un supraconducteur topologique de type chiral, les impuretés scalaires donnent lieu à une hiérarchie complexe de phases non triviales distinctes avec des nombres de Chern élevés. Deuxièmement, nous proposons et étudions théoriquement une nouvelle plate-forme prometteuse que nous appelons «la chaîne dynamique de Shiba», c'est-à-dire une chaîne d'impuretés magnétiques classiques dans un supraconducteur en ondes s avec des spins qui précessent. Nous montrons que cette approche peut être utilisée non seulement pour créer une phase supraconductrice topologique, mais surtout pour contrôler les transitions de phase topologiques au moyen de la dynamique de la texture de la magnétisation. Ce manuscrit est organisé comme suit. Dans la première partie, les informations d'introduction essentielles sur la supraconductivité, les oscillations de Friedel et les états de Yu-Shiba-Rusinov sont fournies. La deuxième partie est consacrée à la polarisation en spin des états Yu-Shiba-Rusinov et aux propriétés qui pourraient être extraites au moyen de la microscopie par effet tunnel résolu en spin. Dans la dernière partie, deux configurations proposées pour l'ingénierie de phases topologiques, basées sur les états induits par les impuretés, sont présentées, suivies de conclusions, d’un bref résumé des réalisations de cette thèse et enfin d’une discussion de possibles directions futures
In this manuscript we first revisit the physics of Yu-Shiba-Rusinov subgap states, focusing on their spin polarisation. We start by showing theoretically that we can extract a considerable amount of information about the host superconductor, by analysing spin-polarised local density of states related to the presence of magnetic impurities. First, we demonstrate that the spin-orbit coupling in two-dimensional and one-dimensional systems, both superconducting and metallic, can be read-off directly and unambiguously via spin-resolved STM. We analyse the impurity-induced oscillations in the local density of states. In particular, we focus on the Fourier transform (FT) of the Friedel oscillations and we note that high-intensity FT features appear at a wave vector given by twice the inverse spin-orbit length. Second, in unconventional superconductors with both s-wave and p-wave pairing, by analysing the spin-resolved spectral structure of the Yu-Shiba-Rusinov states it is possible to determine the dominating pairing mechanism. Most strikingly, we demonstrate that a careful analysis of spin-polarised density of states allows not only to unambiguously characterise the degree of triplet pairing, but also to define the orientation of the triplet pairing vector, also known as the d-vector.Finally, we discuss two different ways of engineering and controlling topological phases with both scalar and magnetic impurities. We start with providing a microscopic theory of scalar impurity structures on chiral superconductors. We show that given a non-trivial chiral superconductor, the scalar impurities give rise to a complex hierarchy of distinct non-trivial phases with high Chern numbers. Second, we propose and study theoretically a new promising platform that we call 'dynamical Shiba chain', i.e. a chain of classical magnetic impurities in an s-wave superconductor with precessing spins. We have shown that it can be employed not only for engineering a topological superconducting phase, but most remarkably for controlling topological phase transitions by means of magnetisation texture dynamics.This manuscript is organised as follows. In the first part, the essential introductory information on superconductivity, Friedel oscillations and Yu-Shiba-Rusinov states is provided. The second part is dedicated to spin polarisation of Yu-Shiba-Rusinov states and the properties that could be extracted by means of spin-resolved STM measurements. In the last part, two setups proposed for topological phase engineering based on impurity-induced states are presented, followed by conclusions with a brief summary of the thesis achievements and further directions to pursue

Zarpellon, Juliana. "Estudo de multicamadas com anisotropia magnética perpendicular e sua aplicação em dispositivos emissores de luz polarizada em spin : Spin-LED e VCSEL". Paris 6, 2011. http://www.theses.fr/2011PA066064.

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L'injection et la détection efficace d'un courant polarisé en spin injecté dans les semi-conducteurs est actuellement l'un des grands défis de la spintronique. Une façon de découpler le problème et de remplacer la détection électrique du courant polarisé en spin par une détection optique comme par exemple les dispositifs Spin-LED. Selon les règles de sélection optique, l'injection de spin doit se faire à partir d'une e��lectrode avec l'aimantation perpendiculaure au plan des couches pour connecter le polarisation de la lumière circulaire avec le courant polarisé en spin. Dans ce travail, nous décrivons le développement d'un ensemble de systèmes multicouches (Co/Ni, Co/Pt, CoFeB/Pt) à aimantation perpendiculaire fabriqués par pulvérisation cathodique. L'optimisation et l'études des propriétés magnétiques de ces matériaux nous a finalement permis d'intégrer une structure de type Co/Pt sur un dispositif optique de type LED à base du semiconducteurs AlGaAs / GaAs (proche infrarouge). Un rapport de la polarisation de la lumière de 3,5% a été obtenu à la rémanence, ce qui démontre la faisabilité de fabriquer des dispositifs Spin-LED sans appliquer un champ magnétique externe. Les résultats de ce travail a encouragé le developement d'autres dispositifs intéressants tels que les VCSEL qui ont une plus large gamme d'applications technologiques

Newbold, David Michael. "Inclusive hyperon polarisation studies at the CERN SPS hyperon beam". Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265386.

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Tappero, Rémy. "Approche théorique des structures électroniques et magnétiques et des transitions de phases de systèmes à polarisation de spins (MnS et MnS2) : simulation des spectres de diffraction neutronique". Pau, 1999. http://www.theses.fr/1999PAUU3006.

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La méthode quanto-chimique linear combination of atomic orbitals (L. C. A. O. ) mise en oeuvre dans le programme Crystal nous a permis de déterminer les fonctions d'onde ou orbitales cristallines de systèmes a polarisation de spins (MnS et MnS 2). Les calculs de type unrestrictes hartree-fock (U. H. F. ) ont été conduits soit dans le cadre de l'approximation hartree-fock (H. F. ) soit dans le cadre de la théorie de la fonctionnelle de la densité (D. F. T. ). Dans cette dernière approche, les modèles de correction locaux (local density approximation : L. D. A. ) et non locaux (generalized gradient approximation : G. G. A. ) de la densité électronique ont été utilisés afin de décrire le potentiel d'échange-corrélation. Des propriétés structurales, électroniques et magnétiques du sulfure et du disulfure de manganèse, pris sous différentes formes allotropiques et selon différents arrangements magnétiques ont été déduites du calcul des orbitales cristallines. En particulier, l'échelle de stabilité expérimentale des polymorphes de MnS a pu être retrouvée et pour les plus importants d'entre eux (B 1 et B 3), les arrangements antiferromagnétiques AF II et AF III se sont avérés être les plus stables en accord avec l'expérience. Dans le cadre du modèle de Heisenberg, les constantes de couplage de superéchange entre spins ont été évaluées. Pour les arrangements de spins les plus stables AF II (B 1) et AF III (B 3), les densités atomiques de spin ont été déterminées. Elles confirment le caractère ionique important des composés et ont servi de base à la simulation des spectres de diffraction neutronique. Ces spectres ont été calculés à la fois dans le modèle classique à atomes indépendants (I. A. M. ) et dans les modèles quantiques ab-initio H. F. Ou semi-empirique D. F. T. L'effet de champ cristallin a été déduit et, de la comparaison très satisfaisante avec les données expérimentales, il est ressorti clairement l'importance de calculer exactement le potentiel d'échange électronique.

Zagdoun, Alexandre. "Dynamic Nuclear Polarisation Surface Enhanced NMR Spectroscopy". Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2014. http://tel.archives-ouvertes.fr/tel-01065554.

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Since its discovery in the 1950's, DNP has been a topic of significant interest in magnetic resonance. DNP is the transfer of polarization between single electrons and nuclei, driven by micro-wave irradiation. Since its renaissance at high field in the 90's, due to the introduction of gyrotrons as high-power, high-frequency microwave sources most application of this technique have been samples of biological interest in frozen solution. The long standing interest of our group in the characterization of surface species such as supported catalysts on silica lead us to apply this technique to the study of surfaces. The goal of this thesis is the development of this method, dubbed DNP Surface Enhanced NMR Spectroscopy. To that end, we first introduce new polarizing agents, soluble in organic solvents. The influence of the electron relaxation times on the DNP enhancements is demonstrated and efficient tailored polarizing agents are introduced. The optimization of the sample preparation to obtain optimal sensitivity is also discussed, as well as the interaction between the radical and the surface. These developments made it possible to apply the technique to many functionalized materials, with some examples developed in this manuscript. Finally, the issue of DNP on polarization conductors is discussed, and we show how microcrystals can be efficiently polarized using DNP.

Iacovita, Cristian. "Spin-dependent tunneling into single cobalt-phthalocyanine molecules". Strasbourg, 2009. http://www.theses.fr/2009STRA6058.

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Cette thèse présente une étude des propriétés électroniques polarisés en spin d'une molécule individuélle de cobalt-phthalocyanine (CoPc), qui sont potentiellement intéressantes pour le domaine émergeant de l'électronique de spin. Les résultats expérimentaux sont analysés par des calculs de type DFT en collaborartion avec J. Kortus (Université Technique de Freiberg, Allemagne). Les molécules de CoPc ont été déposés sur des surfaces non-magnétiques et magnétiques, pour ensuite être individuellement étudiés à basse température par un microscope à effet tunnel. Deux aspects fondamentaux sont abordés: l'injection d'électrons polarisés en spin dans une molécule individuelle et le couplage magnétique de cette molécule avec une surface magnétique. En utilisant une pointe de Co polarisée en spin et un nanoîlot des Co comme électrodes magnétiques et la molécule de CoPc comme élément actif, une résonance polarisée en spin est identiée sur le centre de la molécule. Cette résonance, ayant pour origine les orbitals moléculaire d du cobalt, reète l'existence d'états stationnaires des spin. Ces états prouvent notamment que le moment magnetique de CoPc est figé dans une direction " up " ou " down " après adsorption sur la surface de cobalt magnétique. Les calculs DFT montrent que la molécule de CoPc est ferromagnétiquement couplée avec les nanoîlots via deux mécanismes d'échange (direct et superéchange) et illustrent le rôle important joué par les ligands organiques dans le magnétisme mais aussi dans le transport de spin. Des études expérimentales comparatives ont été effectué sur des surfaces non-magnétiques [Au(111) et Cu(111)] où la molécule de CoPc devient non-magnétique après adsorption comme les calculs DFT le prédisent
The thesis presents an experimental study of both the electronic and the spin-polarized properties of single cobalt-phthalocyanine (CoPc) molecules, which are potentially interesting for the emerging eld of molecular spintronics. The CoPc molecules were deposited on a nonmagnetic and a magnetic surface and individually studied at low temperature using a scanning tunneling microscope. Two fundamental aspects of molecular spintronics are addressed, namely the injection of electron spins into a single molecule and the magnetic coupling of the molecule with the underlying magnetic surface. To do so, spin-polarized scanning tunneling spectroscopy is employed to locally inject spin-polarized electron across the vacuum barrier into a single CoPc molecule. Using the spin-polarized Co terminated tip and Co nanoislands of opposite magnetization as magnetic electrodes, and the CoPc molecule as an active element, spin-polarized electronic features are identied over the center of the molecule. The Co nanoislands were grown on Cu(111) and thoroughly calibrated to eliminate electronic artifacts. The stationary spin states of CoPc arise from the d-orbitals of the cobalt ion and reect two molecular spin orientations. DFT calculations establish that CoPc couples ferromagnetically with the Co nanoislands through two exchange mechanisms (direct and superexchange), illustrating the important role played by the organic ligands in the spin-dependent transport properties. Comparative experimental studies are done on non-magnetic surfaces [Au(111) and Cu(111)], where the paramagnetic CoPc becomes non-magnetic upon adsorption, as DFT calculations predict

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Libri sul tema "Polarisation du spin":

Torcal, Mariano. Affective Polarisation in Spain. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332.

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Workshop on ISO Polarisation Observations (1999 ISO Data Centre). Workshop on ISO Polarisation Observations: ISO Data Centre, Villafranca, Spain, 25-28 May 1999. A cura di Laureijs R. J e Siebenmorgen Ralf 1963-. Noordwijk, the Netherlands: ESA Publications Division, 1999.

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Kavokin, Alexey V., Jeremy J. Baumberg, Guillaume Malpuech e Fabrice P. Laussy. Spin and polarisation. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198782995.003.0009.

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In this chapter we consider a complex set of optical phenomena linked to the spin dynamics of exciton-polaritons in semiconductor microcavities. We review a few important experiments that reveal the main mechanisms of the exciton-polariton spin dynamics and present the theoretical model of polariton spin relaxation based on the density matrix formalism. We also discuss the polarisation properties of the condensate and the superfluid phase transitions for polarised exciton-polaritons. We briefly address the polarization multistability and switching in polariton lasers. Finally, the optical spin-Hall and spin-Meissner effects are described.

Kavokin, Alexey V., Jeremy J. Baumberg, Guillaume Malpuech e Fabrice P. Laussy. Polariton Devices. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198782995.003.0012.

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Polariton devices offer multiple advantages compared to conventional semiconductor devices. The bosonic nature of exciton polaritons offers opportunity of realisation of polariton lasers: coherent light sources based on bosonic condensates of polaritons. The final state stimulation of any transition feeding a polariton condensate has been used in many proposals such as for terahertz lasers based on polariton lasers. Furthermore, large coherence lengths of exciton-polaritons in microcavities open the way to realisation of polariton transport devices including transistors and logic gates. Being bosonic spin carriers, exciton-polaritons may be used in spintronic devices and polarisation switches. This chapter offers an overview on the existing proposals for polariton devices.

Verney, Susannah, e Anna Bosco. Politics of Polarisation: Conflictual Competition in Italy, Spain and Greece. Taylor & Francis Group, 2022.

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Verney, Susannah, e Anna Bosco. Politics of Polarisation: Conflictual Competition in Italy, Spain and Greece. Taylor & Francis Group, 2022.

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Verney, Susannah, e Anna Bosco. Politics of Polarisation: Conflictual Competition in Italy, Spain and Greece. Taylor & Francis Group, 2022.

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Verney, Susannah, e Anna Bosco. Politics of Polarisation: Conflictual Competition in Italy, Spain and Greece. Taylor & Francis Group, 2022.

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Workshop on ISO Polarisation Observations: ISO Data Centre, Villafranca, Spain, 25-28 May 1999 (SP). ESA Publications Division, 1999.

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Torres, Maggie. Anarchism and Political Change in Spain: Schism, Polarisation and Reconstruction of the Confederación Nacional Del Trabajo, 19391979. Sussex Academic Press, 2019.

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Capitoli di libri sul tema "Polarisation du spin":

Gabrys, Barbara, Otto Schärpf e Dennis G. Peiffer. "A New Development in Neutron Diffraction: Spin Polarisation Analysis". In Integration of Fundamental Polymer Science and Technology—5, 271–75. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3890-1_33.

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Lin, Fanglei. "Electron Polarization". In Polarized Beam Dynamics and Instrumentation in Particle Accelerators, 155–81. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-16715-7_6.

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AbstractThis chapter focuses on the introduction and discussion of electron polarization. In addition to the gyromagnetic ratio, the most different character of electrons compared to protons is that electrons radiate electromagnetic energy in a circular accelerator. A very small correction has to be applied to the electron spin flip to account for the synchrotron radiation. The different instantaneous spin flip probabilities, up to down and down to up, can build up the electron beam polarization state. However, mostly synchrotron radiation tends to disturb the electron orbital motion that is eventually balanced by the radiation damping along an equilibrium orbit. The electron spin motion is described by the modified Thomas-BMT equation with the radiative spin transition term included. Detail of the electron (de)polarization phenomena is described in this chapter. The lecture is extracted from various early theoretical papers, lectures, thesis and presentations (Lee, Accelerator Physics. World Scientific Publishing, 1999; Buon and Koutchouk, Polarization of Electron and Proton Beams. CERN-SL-94-80-AP, 1994; Montague, Phys. Rep. 113(1):1–96, 1984; Lee, Spin Dynamics and Snakes in Synchrotrons. World Scientific Publishing, 1997; Barber and Ripken, Handbook of Accelerator Physics and Engineering, 1st edn. World Scientific Publishing, 2006; Barber, An Introduction to Spin Polarisation in Accelerators and Storage Rings. Cockcroft Institute Academic Training Winter Term, 2014; Mane, Nucl. Instr. Methods Phys. Res. A 292:52–74, 1990; Berglund, Spin-Orbit Maps and Electron Spin Dynamics for the Luminosity Upgrade Project at HERA. DESY-THESIS-2001-044, 2001; Electron-Ion Collider Conceptual Design Report, 2020).

Hulsebosch, R. J., I. V. Borovykh, P. Gast e A. J. Hoff. "Electron Spin Polarisation in Quinone Reconstituted Photosynthetic Reaction Centers of RB. Sphaeroides R26." In Photosynthesis: Mechanisms and Effects, 825–28. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_194.

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Torcal, Mariano, e Emily Carty. "Partisan Sentiments and Political Trust: A Longitudinal Study of Spain". In Affective Polarisation in Spain, 167–92. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-8.

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Rodríguez, Isabel, Diego Santamaría e Luis Miller. "Open Access: Electoral Competition and Partisan Affective Polarisation in Spain". In Affective Polarisation in Spain, 27–50. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-2.

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Padró-Solanet, Albert, e Joan Balcells. "Media Diet and Polarisation: Evidence from Spain". In Affective Polarisation in Spain, 74–94. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-4.

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Rodon, Toni. "Affective and Territorial Polarisation: The Impact on Vote Choice in Spain". In Affective Polarisation in Spain, 144–66. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-7.

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Lorenzo-Rodríguez, Javier, e Mariano Torcal. "Twitter and Affective Polarisation: Following Political Leaders in Spain". In Affective Polarisation in Spain, 95–121. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-5.

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Torcal, Mariano, e Josep M. Comellas. "Introduction". In Affective Polarisation in Spain, 1–26. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-1.

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Madariaga, Amuitz Garmendia, e Pedro Riera. "Territorial Polarisation after Radical Parties' Breakthrough in Spain". In Affective Polarisation in Spain, 51–73. London: Routledge, 2023. http://dx.doi.org/10.4324/9781003398332-3.

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Atti di convegni sul tema "Polarisation du spin":

AZZURRI, P. "WW PRODUCTION, POLARISATION AND SPIN CORRELATIONS AT LEP". In Proceedings of the 33rd International Conference. World Scientific Publishing Company, 2007. http://dx.doi.org/10.1142/9789812790873_0139.

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Windmolders, R., Donald G. Crabb, Yelena Prok, Matt Poelker, Simonetta Liuti, Donal B. Day e Xiaochao Zheng. "The Strange Quark Polarisation from Charged Kaon Production on Deuterons". In SPIN PHYSICS: 18th International Spin Physics Symposium. AIP, 2009. http://dx.doi.org/10.1063/1.3215669.

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Teryaev, Oleg, G. Y. Prokhorov, A. S. Sorin e Valentin I. Zakharov. "Anomaly and Polarisation in Heavy-Ion Collisions". In 23rd International Spin Physics Symposium. Trieste, Italy: Sissa Medialab, 2019. http://dx.doi.org/10.22323/1.346.0032.

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Barber, D. P., M. Vogt, Donald G. Crabb, Yelena Prok, Matt Poelker, Simonetta Liuti, Donal B. Day e Xiaochao Zheng. "The Invariant Polarisation-Tensor Field For Spin-1 Particles In Storage Rings". In SPIN PHYSICS: 18th International Spin Physics Symposium. AIP, 2009. http://dx.doi.org/10.1063/1.3215751.

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Kurek, Krzysztof, Donald G. Crabb, Yelena Prok, Matt Poelker, Simonetta Liuti, Donal B. Day e Xiaochao Zheng. "Gluon Polarisation in the Nucleon from High Transverse Momentum Hadron Pairs at COMPASS". In SPIN PHYSICS: 18th International Spin Physics Symposium. AIP, 2009. http://dx.doi.org/10.1063/1.3215658.

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Frederix, Rikkert. "Spin Polarisation of ttbar + gamma gamma production at NLO+PS". In Fourth Annual Large Hadron Collider Physics. Trieste, Italy: Sissa Medialab, 2016. http://dx.doi.org/10.22323/1.276.0163.

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Henrot-Versillé, Sophie. "(Some) Polarisation Aspects of the Cosmic Microwave Background". In Proceedings of the 24th International Spin Symposium (SPIN2021). Journal of the Physical Society of Japan, 2022. http://dx.doi.org/10.7566/jpscp.37.011002.

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Jennings, Elise. "Polarisation Observables in Antiproton Proton to Lepton Antilepton Reactions". In Proceedings of the 17th International Spin Physics Symposium. AIP, 2007. http://dx.doi.org/10.1063/1.2750874.

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Reith, Charis, Steven J. White, Michael Mazilu, Alan Miller, Mircea Guina e Janne Konttinen. "Spin relaxation and all-optical polarisation switching in GaInNAs multiple quantum wells". In 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference. IEEE, 2006. http://dx.doi.org/10.1109/cleo.2006.4628693.

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Beggs, D. M., A. B. Young, A. C. T. Thijssen, K. Kuipers e R. Oulton. "Polarisation singularities in photonic crystals for an on-chip spin-photon interface". In 2014 16th International Conference on Transparent Optical Networks (ICTON). IEEE, 2014. http://dx.doi.org/10.1109/icton.2014.6876694.

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