Afin de réduire la consommation de puissance des futures générations de systèmesélectroniques, une solution est d’intégrer de la non-volatilité au sein même des cellulesmémoires. Dans cette optique, l’utilisation du retournement de l’aimantation d’un matériauferromagnétique comme support de l’information a été utilisée initialement dans un conceptde mémoire, la MRAM. La dernière évolution de cette technologie, la SOT-RAM, utilise desphénomènes nouveaux appelés SOTs afin de contrôler la direction de l’aimantation. Parrapport aux générations précédentes (STT-MRAM notamment), elle devrait permettred’améliorer la vitesse d’écriture en conservant une endurance adaptée pour des utilisations enmémoires cache où en mémoire centrale. Le terme SOTs est une dénomination généraledésignant l’ensemble des effets, encore mal connus, liés au couplage spin-orbite et permettantle retournement de l’aimantation d’une cellule mémoire.Ce travail de thèse a eu pour objectif d’étudier les SOTs via un système expérimental demesure quasi-statique basé sur les effets Hall extraordinaires et planaires. Sonimplémentation et la méthode d’analyse associée, ainsi que les considérations théoriquesnécessaires à l’interprétation des résultats sont détaillées dans ce manuscrit. Il a été montréque le retournement de l’aimantation dans des systèmes à aimantation perpendiculaire à basede cobalt-platine ne peut être expliqué par les modèles simples considérés jusqu’à présentdans la littérature. En effet, il a été mis en évidence qu’au moins deux effets simultanés doiventêtre pris en compte pour expliquer les phénomènes observés. Par ailleurs, ceux-ci présententune sensibilité différente à la fois à une altération de la structure cristalline et à une variationde température. / In order to reduce power consumption in next generations’ electronic devices, one potentialsolution is to implement non-volatility in memory cells. In this goal, the magnetizationswitching of a ferromagnetic material has been used in a memory concept: the MRAM. Thelatest development of this technology, called SOT-RAM, is based on new phenomena calledSOTs (Spin-Orbit Torques) in order to control magnetization direction. Contrary to precedentgenerations (STT-MRAM), it should achieve a higher operating speed and an enduranceadapted for cache and main memories applications. SOTs is a generic term referring to all theeffects, linked to the spin-orbit interaction, and that enable magnetization reversal. They areyet not perfectly understood.The main objective of this Ph.D. was then to study these SOTs through a quasi-staticexperimental measurement setup based on anomalous and planar Hall effects. Itsimplementation and the associated analysis method, as well as the required theoreticalconsiderations for data interpretation are detailed in this manuscript. It has been highlightedthat magnetization switching in perpendicularly magnetization cobalt-platinum systemscannot be explained by the simple models considered thus far in the literature. As a matter offact it has been evidenced that at least two effects have to be considered in order to explainobserved phenomena. In addition, they present different susceptibility both to a modificationof the crystal structure and to a temperature change.

A novel experimental setup has been realized to measure weak magnetic moments which can be modulated at radio frequencies (~1–5 MHz). Using an optimized radio-frequency (RF) pickup coil and lock-in amplifier, an experimental sensitivity of 10 -15 Am2 corresponding to 10 -18 emu has been demonstrated with a one second time constant. The detection limit at room temperature is 9.3 10 -16 Am2/√Hz limited by Johnson noise of the coil. In order to demonstrate the sensitivity of this technique it was used to electrically detect the polarized spins in semiconductors in zero applied magnetic fields. For example in GaAs, the magnetic moment due to a small number (~ 7 x 108) of spin polarized electrons generated by polarization modulated optical radiation was detected. Spin polarization was generated by optical injection using circularly polarized light which is modulated rapidly using an electro-optic cell. The modulated spin polarization generates a weak time-varying magnetic field which is detected by the sensitive radio-frequency coil. Using a radio-frequency lock-in amplifier, clear signals were obtained for bulk GaAs and Ge samples from which an optical spin orientation efficiency of ~ 10–20% could be determined for Ge at 1342 nm excitation wavelength at 127 K. In the presence of a small external magnetic field, the signal decayed according to the Hanle Effect, from which a spin lifetime of 4.6 ± 1.0 ns for electrons in bulk Ge at 127 K was extracted. The spin dynamics in n-Ge was further explored and the temperature dependence of the spin lifetime was plotted for a temperature range of about 90 K to 180 K. The temperature dependence of the optical pumping efficiency was also measured though no quantitative conclusions could be derived. The signals observed for semi-insulating GaAs, n-GaAs, GaSb and CdTe which are direct gap semiconductors are much larger than expected (almost two orders of magnitude). An attempt was made to explain this unexpected behavior of these direct gap semiconductors using the spin hall effect.

Les mémoires non-volatiles (MNV) sont l'objet d'un effort de recherche croissant du fait de leur capacité à limiter la consommation statique, qui obère habituellement la réduction des dimensions dans la technologie CMOS. Dans ce contexte, cette thèse aborde plus spécifiquement deux technologies de mémoires non volatiles : d'une part les jonctions tunnel ferroélectriques (JTF), dispositif non volatil émergent, et d'autre part les dispositifs à transfert de spin (TS) assisté par effet Hall de spin (EHS), approche alternative proposée récemment pour écrire les jonctions tunnel magnétiques (JTM). Mon objectif est de développer des modèles compacts pour ces deux technologies et d'explorer, par simulation, leur intégration dans les circuits non-volatiles.J'ai d'abord étudié les modèles physiques qui décrivent les comportements électriques des JTF : la résistance tunnel, la dynamique de la commutation ferroélectrique et leur comportement memristif. La précision de ces modèles physiques est validée par leur bonne adéquation avec les résultats expérimentaux. Afin de proposer un modèle compatible avec les simulateurs électriques standards, nous j'ai développé les modèles physiques mentionnés ci-dessus en langue Verilog-A, puis je les ai intégrés ensemble. Le modèle électrique que j'ai conçu peut être exploité sur la plate-forme Cadence (un outil standard pour la simulation de circuit). Il reproduit fidèlement les comportements de JTF. Ensuite, en utilisant ce modèle de JTF et le design-kit CMOS de STMicroelectronics, j'ai conçu et simulé trois types de circuits: i) une mémoire vive (RAM) basée sur les JTF, ii) deux systèmes neuromorphiques basés sur les JTF, l'un qui émule la règle d'apprentissage de la plasticité synaptique basée sur le décalage temporel des impulsions neuronale (STDP), l'autre mettant en œuvre l'apprentissage supervisé de fonctions logiques, iii) un bloc logique booléen basé sur les JTF, y compris la démonstration des fonctions logiques NAND et NOR. L'influence des paramètres de la JTF sur les performances de ces circuits a été analysée par simulation. Finalement, nous avons modélisé la dynamique de renversement de l'aimantation dans les dispositifs à anisotropie perpendiculaire à transfert de spin assisté par effet Hall de spin dans un JTM à trois terminaux. Dans ce schéma, deux courants d'écriture sont appliqués pour générer l'EHS et le TS. La simulation numérique basée sur l'équation de Landau-Lifshitz-Gilbert (LLG) démontre que le délai d'incubation de TS peut être éliminé par un fort EHS, conduisant à la commutation ultra-rapide de l'aimantation, sans pour autant requérir une augmentation excessive du TS. Nous avons appliqué cette nouvelle méthode d'écriture à la conception d'une bascule magnétique et d'un additionneur 1 bit magnétique. Les performances des circuits magnétiques assistés par l'EHS ont été comparés à ceux écrits par transfert de spin, par simulation et par une analyse fondée sur le modèle théorique. / Non-volatile memory (NVM) devices have been attracting intensive research interest since they promise to solve the increasing static power issue caused by CMOS technology scaling. This thesis focuses on two fields related to NVM: the one is the ferroelectric tunnel junction (FTJ), which is a recent emerging NVM device. The other is the spin-Hall-assisted spin-transfer torque (STT), which is a recent proposed write approach for the magnetic tunnel junction (MTJ). Our objective is to develop the compact models for these two technologies and to explore their application in the non-volatile circuits through simulation.First, we investigated physical models describing the electrical behaviors of the FTJ such as tunneling resistance, dynamic ferroelectric switching and memristive response. The accuracy of these physical models is validated by a good agreement with experimental results. In order to develop an electrical model available for the circuit simulation, we programmed the aforementioned physical models with Verilog-A language and integrated them together. The developed electrical model can run on Cadence platform (a standard circuit simulation tool) and faithfully reproduce the behaviors of the FTJ.Then, using the developed FTJ model and STMicroelectronics CMOS design kit, we designed and simulated three types of circuits: i) FTJ-based random access memory (FTRAM), ii) two FTJ-based neuromorphic systems, one of which emulates spike-timing dependent plasticity (STDP) learning rule, the other implements supervised learning of logic functions, iii) FTJ-based Boolean logic block, by which NAND and NOR logic are demonstrated. The influences of the FTJ parameters on the performance of these circuits were analyzed based on simulation results.Finally, we focused on the reversal of the perpendicular magnetization driven by spin-Hall-assisted STT in a three-terminal MTJ. In this scheme, two write currents are applied to generate spin-Hall effect (SHE) and STT. Numerical simulation based on Landau-Lifshitz-Gilbert (LLG) equation demonstrates that the incubation delay of the STT can be eliminated by the strong SHE, resulting in ultrafast magnetization switching without the need to strengthen the STT. We applied this novel write approach to the design of the magnetic flip-flop and full-adder. Performance comparison between the spin-Hall-assisted and the conventional STT magnetic circuits were discussed based on simulation results and theoretical models.

The spin transport and dynamics of optically injected spin polarized carri- ers are studied with a high spatial and/or time resolution in semiconductor GaAs-based heterostructures in multiple transport regimes. An unexpectedly long-scale and high-speed spin diffusion transport is observed in a long-lived electron sub-system induced optically at an undoped single GaAs/AlGaAs heterointerface. A diffusion and drift-dominated spin transport is investi- gated using an electrical spin-detection via the inverse spin Hall effect in doped GaAs-based systems at room and low temperatures. It is shown that the inverse spin Hall signal and the spin transport parameters can be con- trolled by a direct application of an electric field or by expanding a depleted zone of a planar pn-junction.

Les dispositifs spintroniques exploitent le degré de liberté du spin électronique pour traiter l'information. Dans cette thèse, nous étudions les propriétés de transport quantique dépendant du spin pour optimiser les performances des composants associés. Par l’approche ab initio, nous calculons la magnétorésistance à effet tunnel (tunneling magnetoresistance, TMR), l’effet Hall de spin (spin Hall effect, SHE) et l’efficacité de l’injection de spin (spin injection efficiency, SIE). Nous montrons ainsi que les métaux lourds (heavy metals, HM) influencent la TMR dans des jonctions tunnel magnétiques (magnetic tunnel junctions, MTJs) à base de MgO. L’utilisation de W, Mo, ou Ir peut améliorer la TMR. De plus, le dopage par substitution aide à optimiser le SHE dans les HMs, ce qui renforce les angles de Hall de spin (SHA) pour rendre plus efficace le renversement d’aimantation par couple spin-orbite (spin-orbit torque, SOT) dans les MTJ. Afin de contourner les problèmes induits par le désaccord de maille entre couches ferromagnétiques et MgO, nous avons conçu une MTJ basée sur l'hétérojonction VSe₂/MoS₂ de van der Waals (vdW) et calculons la TMR à température ambiante. L’apparition d’effets de résonance tunnel permet d’utiliser la tension appliquée pour moduler la TMR dans cette structure. Nous proposons également d’y favoriser le SOT en utilisant des matériaux 2D avec un fort SHE. MoTe₂ et WTe₂ apparaissent comme de bons candidats. Ces dichalcogénures de métaux de transition (transition metal dichalcogenides, TMDC) présentent un fort SHE ainsi que de grands SHA grâce à leur faible conductivité électrique. Enfin, motivés par la demande d'un dispositif commutable bidimensionnel à grande longueur de diffusion spin, nous étudions un système d'injection de spin dans le silicène et obtenons des SIE élevés sous tension appliquée. L’ensemble de ces travaux apportent un éclairage pour la recherche de nouveaux dispositifs spintroniques. / Spintronics devices manipulate the electron spin degree of freedom to process information. In this thesis, we investigate spin-dependent quantum transport properties to optimize the performances of spintronics devices. Through ab initio approach, we research the tunneling magnetoresistance (TMR), spin Hall effect (SHE), as well as spin injection efficiency (SIE). It has been demonstrated that heavy metals (HMs) are able to modulate TMR effects in MgO-based magnetic tunnel junctions (MTJs), and tungsten, molybdenum, and iridium are promising to enhance TMR. Moreover, substitutional atom doping can effectively optimize SHE of HMs, which would strengthen spin Hall angles (SHAs) to achieve efficient spin-orbit torque (SOT) switching of MTJs. To eliminate the mismatch between ferromagnetic and barrier layers in MgO-based MTJs, we design the MTJ with bond-free van der Waals (vdW) heterojunction VSe₂/MoS₂ and report the room-temperature TMR. The occurrence of quantum-well resonances enables voltage control to be an effective method to modulate TMR ratios in vdW MTJ. We put forward the idea of SOT vdW MTJ, which employs SOT to switch vdW MTJ and requires vdW materials with strong SHE. Research on MoTe₂ and WTe₂ verifies the possibility of realizing this idea. Both of them are layered transition metal dichalcogenides (TMDC) and exhibit strong SHEs, as well as large SHAs thanks to their low electrical conductivity. Lastly, motivated by the demand of a two-dimensional (2D) switchable device with long spin diffusion length, we construct the spin injection system with silicene monolayer, and reveal high SIEs under electric fields. Works in this thesis would advance the research of spintronics devices.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-03-15T12:16:24Z No. of bitstreams: 1 arquivototal.pdf: 5169144 bytes, checksum: 66d534e3f0c0c59bf5d35a45290fa390 (MD5) / Made available in DSpace on 2016-03-15T12:16:24Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5169144 bytes, checksum: 66d534e3f0c0c59bf5d35a45290fa390 (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this thesis, we propose an experimental setup for the study of Landau quantization and associated effects in a two-dimensional ultracold atomic gas. Gauge fields can emerge in the equation of motion for the optically addressed ultracold atoms. To this end, spatially dependent dark states are necessary for the internal states of the atoms. A tripod level scheme yields two degenerate dark states which can leads to either an Abelian U(1) U(1) gauge field or a non-Abelian SU(2) gauge field. Using a suitable laser configuration, we obtain a uniform U(1) U(1) magnetic field which causes the atoms organize themselves in Landau levels. The strength of the effective magnetic field depends on the relative intensity of the lasers beams at the atomic cloud. We estimate the degeneracy of the energy levels for an atomic gas formed by atoms of 87Rb. In addition, we establish the experimental conditions to reach the lowest Landau level regime. In the zero-temperature limit, we realize the emergence of magnetic oscillations in the atomic energy and its derivative as function of the inverse of the effective magnetic field (de Haas van Alphen effect). The period of the de Haas van Alphen oscillation allow us to determine area of the Fermi circle for the atomic gas via an Onsager-like relation. We also show that detuning the a laser from the two-photon resonance we generate a parabolic scalar potential that laterally confines the atoms. As a consequence, the Landau levels degeneracy is removed, since the energy spectrum depends explicitly on the transverse atomic momentum. We show that the Landau levels presents a reminiscent degeneracy when the boundaries conditions are considered. The residual degeneracy occurs when different energy levels overlap. We map the residual degeneracy points as a function of the effective magnetic field. Finally, we present an experimental scheme for observing the spin Hall effect for ultracold atoms in a tripod configuration. / Nesta tese, propomos um arranjo experimental para o estudo da quantização de Landau e efeitos associados em um gás atômico ultrafrio bidimensional. Campos de calibre podem surgir na equação de movimento para átomos ultrafrios oticamente vestidos. Para que isto ocorra, estados escuros espacialmente dependentes são necessários a partir dos estados internos dos átomos. Átomos numa configuração de níveis de energia do tipo tripod produzem dois estados escuros degenerados, que podem levar a campos de calibre Abelianos U(1) U(1) ou não-Abelianos SU(2). Utilizando uma configuração adequada de lasers, mostramos que é possível se produzir um campo magnético sintético uniforme U(1) U(1) que atua nos átomos neutros fazendo-os se organizarem em níveis de Landau. A intensidade do campo efetivo depende da intensidade relativa dos feixes de luz na nuvem atômica. Estimamos a degenerescência dos níveis de energia para um gás atômico formado por átomos de 87Rb e estabelecemos as condições experimentais para que seja atingido o regime em que todos os átomos populam unicamente o nível de Landau menos energético. Considerando o limite de temperatura nula, verificamos o surgimento de oscilações magnéticas na energia e em sua derivada como uma função do inverso do campo magnético efetivo (efeito de Haas van Alphen). O período da oscilação magnética nos permite determinar a área do círculo de Fermi para o gás atômico através de uma expressão similar a de Onsager para sistemas eletrônicos. Mostramos também que dessintonizando um dos lasers em relação à ressonância de dois fótons geramos um potencial escalar parabólico que faz com os átomos sejam lateralmente confinados. Isto resulta na remoção da degenerescência dos níveis de Landau, uma vez que a energia depende explicitamente do momento atômico transverso. Demonstramos que, aplicando condições periódicas de contorno ao sistema, temos o surgimento de uma degenerescência residual. A degenerescência remanescente ocorre quando diferentes níveis de energia se superpõem. Mapeamos os pontos de degenerescência como uma função do campo magnético efetivo. Por fim, apresentamos um esquema experimental para a observação do efeito spin Hall para átomos ultrafrios em uma configuração tripod.

In the present thesis, magnetization reversal in both out-of-plane and in-plane magnetized thin lms and in devices fabricated out of those lms are explored. Pt/Co/Pt stacks with ultrathin Co layer were in-estimated initially for understanding their magnetic properties in this thesis. These perpendicular magnetized systems are good candidates for magnetic hard disc drives due to their large anisotropy, which may allow miniaturization of magnetic data storage devices. The spin Hall e ect mediated current-induced magnetization reversal in patterned Pt/Co/Pt devices were extensively investigated. Investigation of the magnetization reversal by means of a current instead of a magnetic eld is necessary to explore the possibilities of solid state magnetic memory devices. This is the primary motivation behind the investigation of current-induced magnetization reversal in Pt/Co/Pt system, in this thesis. Another important proposal for magnetic data storage is the race track memory, where the domain walls separating magnetic domains (in in-plane or out-of-plane magnetized materials) are moved by using a current. This involves a great deal of understanding of the domain wall motion in Nano-conduits under applied magnetics ends, and currents and also its interaction with engineered geometrical features. In this thesis work, magnetic led-driven domain wall pinning and deepening experiments on in-plane magnetized nanowires of perm alloy were performed to un-distend this interaction and the e act of domain wall chirality. In chapter 1, a general introduction to di errant data storage technologies and the current progress in the leg of spintronic is presented. This will highlight a perspective of this thesis work with respect to the present day research in spintronic and magnetization reversal studies. In chapter 2, a basic background of magnetism using the micromag-netic framework is illustrated. A brief introduction to magnetic domain walls is also presented. The Landau-Lifshitz-Gilbert dynamical equation is discussed and some case studies applied to a single domain particle with uniaxial anisotropy under the effect of spin-orbit torque are illu trated. The basics of spin-orbit coupling leading to spin Hall e ect is also explain In chapter 3, most of the essential experimental tools along with their basic working principles are described. Extensive e orts have been in-vested in designing and building the experimental tools. These include custom designs of a sputter deposition system, an ultra-high vacuum chamber for pulsed laser ablation, a magneto-optic Kerr e ect magne-tometer, a Kerr imaging system and a magneto-transport setup. All of these experimental setups have been automated, details of which are brie y discussed in this chapter. The Kerr imaging system was designed to measure hysteresis loops, observe domain wall motion and to measure domain wall velocity under applied magnetic elds and electric current. The magneto-transport setup was used for studying the domain wall pinning and depinning experiments in permalloy nanowires. In chapter 4, the optimization process for obtaining perpendicular mag-netic anisotropy in Pt/Co/Pt lms is described. The spin reorientation transition with varying thickness of Co (from 1.5 nm down to 0.35 nm) was studied. The magnetization easy axis direction changes from in-plane to out-of-plane as the thickness of Co is reduced. The dependence of Curie temperatures of ultrathin Co lms, with thickness as low as 0.35 nm, on the underlayer Pt thickness and its crystallinity was studied in detail. The e act of Ta but err layer on the texture of the Pt lm, and on the Curie temperature of the Pt/Co/Pt system was evaluated. To gain further insight of the role of the bottom Pt/Co and the top Co/Pt interfaces, ultrathin Cu lbs were inserted at the respective interfaces, and the anisotropy and magnetization reversal behaviour of these lbs were investigated. In chapter 5, studies on current-induced magnetization reversal in mi-corn sized wires of Pt/Co/Pt trilete is presented. The spin Hall e act assisted spin-orbit torque was used to reversibly switch the magnetization of these devices with and without the help of an external magnetic led. Since both the top and bottom layers are Pt, any contribution from Rashia e act towards spin-orbit torque could be ignored. By preparing devices with unequal top and bottom Pt thicknesses, a net spin-orbit torque could be applied to the magnetization of the Co layer. The thickness gradient/induced anisotropy in the Co layer was utilized to experimentally investigate current-induced deterministic switching. Sin-gel domain simulations with spin-orbit torque were also carried out to understand the mechanism of deterministic switching of magnetization in Pt/Co/Pt devices. This study is expected to have made sign cant contributions and to open up the possibilities of further investigation in the studies of spin-orbit torque in Pt/Co/Pt systems for solid state magnetic memory devices. In chapter 6, magnetic led-induced reversal in systems with in-plane magnetic anisotropy is presented. Here the e act of the width of a Nanos-trip on the anisotropy of a soft magnetic material like perm alloy was in-estimated. By introducing a nucleation pad to one end of the perm alloy nanowire, a single domain wall was generated at the junction with apple-cation of a proper magnetic led sequence. This domain wall could be in-jested into the nanowire by a magnetic led and pinned at a geometrical constriction inside the nanowire. The statistics of domain wall pinning and deepening processes indicated two di errant types of domain walls involved in the reversal process. With the assistance of micro magnetic simulations the domain walls were ident end as vortex walls of di errant chirality’s. Thus the interaction of domain walls with a Nano constriction and its dependence on the chirality of domain walls are understood. In chapter 7, a brief summary of the results obtained during the course of investigations is presented. An outlook presented at the end will help the readers of this thesis to understand the important research problems in this area and their potential future aspects.

Les travaux présentés dans cette thèse ont pour objectif d’apporter à la physique mésoscopique un éclairage concernant la compréhension des propriétés de transport électroniques d’une classe de matériaux récemment découverts : les isolants topologiques.La première partie de ce manuscrit est une introduction aux isolants topologiques, mettant en partie l’accent sur leurs spécificités par rapport aux isolants "triviaux" : des états de bords hélicaux (dans le cas de l’effet Hall quantique de spin en 2 dimensions) ou de surface relativistes (pour les isolants topologiques tridimensionnels) robustes vis-à-vis du désordre.La deuxième partie propose une sonde de l’hélicité des états de bords de l’effet Hall quantique de spin en étudiant les propriétés remarquables de l’injection de paires de Cooper dans cette phase topologique.La troisième partie étudie la diffusion des états de surface des isolants topologiques tridimensionnels dans le régime cohérent de phase. L’étude de la diffusion, de la correction quantique à la conductance (antilocalisation faible) et de l’amplitude des fluctuations universelles de conductance de fermions de Dirac sans masse est présentée. Cette étude est aussi menée dans la cas d’états de surface dont la surface de Fermi présente la déformation hexagonale observée expérimentalement. / The works presented in this thesis intend to contribute to condensed matter physics in the understanding of the electronic properties of a recently discovered class of materials : the topological insulators.The first part of this memoir is an introduction to topological insulators, focusing on their specifities compared to "trivial" insulators : helical edge states (in the two dimensional quantum spin Hall effect) or relativistic surface states (for three dimensional topological insulators) both robust agiant disorder.The second part proposes a new way to probe the unique properties of the helical edge states of quantum spin Hall effect via the injection of Cooper pair from a superconductor.The third part deals with the diffusion of the three dimensional topological insulator surface states, in the phase coherent regime. The diffusion, the quantum correction to conductivity, and the amplitude of the universal conductance fluctuations are studied. This study is also led in the experimentally relevant case where the Fermi surface presents a hexagonal deformation.

Cette thèse porte sur l’étude des courants de spin et de l’effet Hall de spin dans des nanostructureslatérales. Des vannes de spin latérales Py/Al, Py/Cu et Py/Au, ont été fabriquées parlithographie électronique, puis optimisées et caractérisées par des mesures de magnéto-transport.Des mesures non locales, de GMR, et d’effet Hanle ont ainsi été enregistrées à 300K et 77K. De l’optimisation des vannes de spin latérales a découlé l’observation de fortes amplitudes designal de spin. De plus, les effets du confinement latéral et vertical de l‘accumulation de spin,par utilisation d’un canal non-magnétique confiné ou de barrières tunnel AlOx, ont été mis enévidence expérimentalement et décrits théoriquement. Des simulations par éléments finis et desanalyses basées sur les modèles de diffusion 1D ont été développées, permettant l’extraction de lapolarisation effective Peff et de la longueur de diffusion de spin lNsf des données expérimentales.Enfin, l’effet Hall de spin dans des matériaux à fort angles de Hall (Pt, aliage d’Au) a étéétudié dans des hétérostructures latérales et par pompage de spin à la résonance ferromagnétique. / This PhD thesis focus on the study of spin currents and of the spin Hall effect in lateralnano-structures. Lateral spin-valves based on Py/Al, Py/Cu and Py/Au, fabricated by meansof electron-beam lithography, have been optimized and characterized using magneto-resistancemeasurements. Non-local, GMR and Hanle effect measurements have been recorded at 300K and77K. The optimization of these lateral spin-valves allowed the observation of high spin signalamplitudes. Lateral and vertical confinement effects on the spin accumulation, by using confinednon-magnetic channel and AlOx tunnel barriers, were evidenced experimentally and describedtheoretically. Finite Elements Method simulations and analyses based on a 1D diffusion modelhave been developed, allowing the extraction from our experimental data of the effective spinpolarization Peff and of the spin diffusion length lNsf .Finally, the spin Hall effect of materials with high spin Hall angles (Pt, Au alloys) has beenstudied using both hybrid lateral nano-structures and spin pumping ferro-magnetic resonance.