O presente estudo tem como tema a análise da trajetória de inovação para spin-offs acadêmicas, enfocando o estudo de caso da SOLINOVA, empresa que busca inovar na área de energia com soluções aplicadas ao agronegócio. O problema de pesquisa pode ser sintetizado na questão: Como uma spin-off acadêmica inova e financia seu processo de nascimento, sobrevivência e crescimento a partir de capital de inovação? Em síntese, pretende-se buscar um aprofundamento sobre o sistema de inovação existente no país, além de verificar as oportunidades de financiamento à inovação disponível para empresas desta natureza no Brasil. Basicamente, foram dois os procedimentos metodológicos adotados: em um primeiro momento, foi realizada a pesquisa bibliográfica sobre a temática abordada e, em momento posterior, o estudo de caso por meio de observação direta e entrevistas semiestruturadas da empresa SOLINOVA Inovação Tecnológica e Empresarial, que nasceu de um spin-off do Laboratório de Eficiência Energética e Simulação de Processos (LEESP) na Incubadora de Empresas Inovadoras do Agronegócio de Pirassununga (UNICETec) da Universidade de São Paulo, localizado na Faculdade de Zootecnia e Engenharia de Alimentos, Campus de Pirassununga - SP. O contato direto foi realizado com os envolvidos na área de gestão e análise de documentos, visando traçar a trajetória de inovação com base nos históricos da empresa e assim atingir os objetivos propostos com o suporte teórico adquirido. O estudo relatou, ao final, as trajetórias de inovação da SOLINOVA e recursos alavancados por estratégia para acionar capital de inovação públicos e privados, que foram decisivos para a sobrevivência e desenvolvimento das tecnologias internalizadas pela empresa no país. / The present study has as its theme the analysis of the innovation trajectory for academic spin-offs, focusing on the case study of SOLINOVA, a company that seeks to innovate in the area of energy with solutions applied to agribusiness. The research problem can be summed up in the question: How does an academic spin-off innovate and thereby finance its birth, growth and survival process from capital to innovation? In summary, it intends to seek a deepening of the existing system of innovation in the country, as well as to verify the opportunities for financing innovation available to companies of this nature in Brazil. Basically, two methodological procedures were adopted: firstly, a bibliographical research on the subject was carried out and, at a later time, the case study by means of direct observation and semi-structured interviews of the company SOLINOVA Technological and Business Innovation, which was born from a spin-off of the Laboratory of Energy Efficiency and Process Simulation (LEESP) at the Agribusiness Innovation Incubator of Pirassununga (UNICETec) of the University of São Paulo, located at the Faculty of Animal Science and Food Engineering, Pirassununga Campus - SP. The direct contact was made with those involved in the area of document management and analysis, aiming at tracing the innovation trajectory based on company history and thus achieving the proposed objectives with the theoretical support acquired. In the end, the study reported the SOLINOVA innovation trajectories and resources leveraged by strategy to drive public and private innovation capital, which were decisive for the survival of the development of technologies internalized by the company in the country.

Des mesures d’ondes de spin propagatives ont été réalisées pour caractériser deux effets de l’interaction spin-orbite ainsi que le transport électrique dépendant du spin. Les effets du couplage spin-orbite ont été étudiés dans des bicouches nickel-fer/platine. Dans ces films, les fréquences de deux ondes de spin contre-propageantes ne sont pas les mêmes, ce qui est attribué à l’effet combiné d’une interaction magnétique chirale appelée interaction Dzyaloshinskii-Moriya et d’une asymétrie dans l’épaisseur du film magnétique. En appliquant le courant électrique dans ce système nous avons observé une modification du taux de relaxation de l’onde de spin qui est attribuée au transfert de spin induit par effet Hall de spin. D’autre part, les études de propagation d’ondes de spin dans une couche mince de fer épitaxié à température ambiante ont montré une polarisation en spin du courant électrique de 83%, ce qui est attribué à une forte asymétrie du couplage électron-phonon. / Propagating spin wave measurements were realised to characterize two spin-orbit related phenomena, as well as spin dependent electrical transport. The effects of spin-orbit coupling have been studied in nickel-iron/platinum bilayers. It has been shown that in these films the frequencies of two counter-propagating spin waves are not the same, which is attributed to the combined effects of a chiral magnetic interaction named Dzyaloshinskii-Moriya interaction and an asymmetry of the magnetic properties across the film thickness. By applying an electrical current in such system we have observed a modification of the spin wave relaxation rate due to the spin transfer torque induced by spin Hall effect. On the other hand, from the study of spin wave propagation in thin epitaxial iron films at room temperature, a degree of spin polarization of the electrical current of 83% was extracted, which is attributed to a significant spin-asymmetry of the electron-phonon coupling.

NMR spectroscopy has evolved into one of the most important characterization techniques in chemistry with which it is possible to obtain valuable structural, dynamical, and mechanistic information. Most applications of NMR have however been limited to the use of nuclei having spin quantum numbers of 1/2. This thesis discusses the developments that have been advanced in order to extract quantitative structural information from the NMR spectroscopy of quadrupolar nuclei (spin, I>1/2) which account for the vast majority of the NMR-active nuclei. In a first part of the thesis, a NMR crystallographic method is developed which uses the electric field gradient tensor measured at the nuclear sites as an experimental constraint in DFT-based crystal structure refinements. This inclusion of experimental data into crystal structure refinements enables the determination of higher quality, and experimentally-relevant, structures. We apply this new methodology in order to determine higher quality crystal structures for the non-linear optical material Na2B2Al2O7, sodium pyrophosphates, and the near-zero thermal expansion material ZrMgMo3O12. In a second part of this thesis, experimental techniques are developed for the measurement of spin-spin coupling between pairs of quadrupolar nuclei; the measurement of spin-spin coupling carries with it extremely valuable distance and connectivity information. Using DOR NMR, heteronuclear residual dipolar coupling as well as homonuclear J coupling multiplets can be observed. Notably, the J coupling between quadrupolar nuclei can still be measured in A2 spin systems, unlike in the case of pairs of spin-1/2 nuclei. The theory that was developed for the characterization of these multiplets was extended for the general simulation of exact NMR spectra of quadrupolar. This program, known as QUEST, is now free to use by anyone in the scientific community. Pulsed J-resolved NMR experiments are then described which enable the facile measurement of J and dipolar coupling in homonuclear pairs of quadrupolar nuclei. Notably, the J splitting is greatly amplified in A2 spin systems which provides strong structural information and enables the precise detection of smaller J coupling constants. These techniques are applied towards directly studying gallium metal-metal bonding interactions as well as boron-boron bonds in diboron compounds of importance in β-boration chemistry.

Orientador: Pascoal José Giglio Pagliuso / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-24T07:35:54Z (GMT). No. of bitstreams: 1 HolandaJunior_LinoMartinsde_D.pdf: 3936724 bytes, checksum: 5a1e9e5453184dac769d35041c7414d0 (MD5) Previous issue date: 2014 / Resumo: Nesta Tese de Doutorado desenvolvemos estudos de Ressonância de Spin Eletrônico (ESR) em compostos intermetálicos, incluindo os férmions pesados ?-YbAlB4, ?-YbAlB4 and ? -YbAlxFe1-xB4, os metais ?-LuAlB4, AlB2 e o isolante Kondo, FeSi. Nossas medidas foram feitas em um espectrômetro modelo ELEXSYS-CW Bruker usando uma cavidade ressonante do tipo TE102 para a faixa de frequência em banda X (?~ 9.4GHz). A técnica de Ressonância de Spin Eletrônico aplicada aos compostos Férmions pesados foi sempre um desafio devido a presença de fortes correlações eletrônicas que tendem a alargar as linhas de ESR. Porem, nos últimos anos essa técnica ganhou renovado interesse após a descoberta do sinal de ESR na rede Kondo YbRh2Si2. Após esse trabalho, ESR voltou a ser considerada uma técnica importante para explorar os elétrons 4f e suas interações microscópicas em compostos de terras raras, uma vez que ela sonda diretamente o íon no sitio da rede. A motivação desse trabalho e, portanto, usar a técnica de ESR para entender a dinâmica dos elétrons 4f pesados em uma rede de Kondo, para os novos compostos férmions pesados ?-YbAlB4, -YbAlB4 and ?-YbAlxFe1-xB4. Neste trabalho buscou-se utilizar a técnica de ESR nesses compostos para alcançar o entendimento microscópio dos critérios que permitem a observação de um sinal de ESR em férmios pesados. Alem do mais, quando o sinal e observado, a sonda de ESR e propícia para acompanhar a evolução dos elétrons 4f em altas temperaturas para quase-partículas pesadas em baixas temperaturas. Nossas observações nos permitiram propor um cenário qualitativo baseado na existência de um modo ressonante acoplado entre ons Kondo e os elétrons de condução. Nos discutimos as características físicas gerais para que compostos férmios pesados sejam candidatos a apresentarem tal sinal de ESR. Ainda neste trabalho, estudamos os compostos intermetálicos ?-LuAlB4, AlB2 e FeSi com propriedades estruturais ou eletrônicas similares as dos compostos ?-YbAlB4, ?-YbAlB4 and ?-YbAlxFe1-xB4 em busca de uma generalizac~ao mais abrangente do cenário proposto neste trabalho / Abstract: In this work, we have performed an Electron Spin Resonance (ESR) study in intermetallic compounds including the heavy fermions ?-YbAlB4, ?-YbAlB4 and ? -YbAlxFe1-xB4, the Fermi liquid metals ?-LuAlB4, AlB2 and the Kondo insulator, FeSi. Our measurements were made on a spectrometer Bruker CW-model ELEXSYS using a resonant cavity TE102 in X Band ( ?~ 9.4GHz). The Electron Spin Resonance technique applied to heavy fermions compounds was little explored due to difficulty in finding ESR signal of Kondo ions due to the large coupling between the resonating spins and conduction electrons. However, in recent years this technique has become focus of great attention especially after the discovery of the ESR signal in a Kondo lattice YbRh2Si2. In this context, ESR was brought to the scene as one of the main techniques to bring insights to this problem since it could probe directly the f electrons of Kondo ions and their interaction with the conduction electrons. The motivation of this work is to use the ESR technique to investigate new heavy fermions compounds and to understand when these systems can present an ESR signal. In these cases ESR can help to understand more deeply how localized f electrons at high-T evolve to itinerant heavy quasi-particles in a low-T metallic state. Our observations for ?-YbAlB4, -YbAlB4 and ?-YbAlxFe1-xB4, allowed us to make some qualitative speculations about this phenomenon and within this scenario, we propose some general characteristics for heavy fermions compounds to become candidates to present ESR signal. In this work we have also measured ?-LuAlB4, AlB2 and the Kondo insulator, FeSi, in an attempt to generalize the ESR results found for ?-YbAlB4, ?-YbAlB4 and ?-YbAlxFe1-xB4 to a more broad family of compounds / Doutorado / Física / Doutor em Ciências

Spintronics, also known as spin electronics, or magnetoelectronics, refers to the study of the role that electron and (less frequently) nuclear spins play in solid state physics, and a group of devices that specifically exploit both the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge. As a principal type of spintronic device, a spin-valve is a device that uses ferromagnetic electrodes to polarize and analyze the electronic spins. The electrical resistance of the device depends sensitively on the relative magnetization of its two ferromagnetic electrodes, a phenomenon referred to as Giant Magnetoresistance (GMR). Having been successfully applied in the field of data storage, GMR also shows potential for future logic devices. Organic semiconductors possess many advantages in electronic device applications. Therefore, using organic semiconductors in spintronics is very interesting and promising, in part, because of their exceptionally long spin-decoherence times. This thesis concerns itself with the scientific study of magnetic field and spin effects in organic spin valves (OSV) and organic light emitting diodes (OLED). Three projects were finished, achieving a better understanding of the transportation of charge and spin carriers inside organic films, and paving the way to enhancing the spin diffusion length and the organic magnetoresistance (OMAR) effect. Firstly, C60 films were used as the spin-transport layer of OSV devices, because of its low hyperfine coupling and high mobility, which prior work suggested to be beneficial. Subsequently we studied the spin injection and transport properties by measuring the devices' magnetoresistance (MR) response at various biasing voltages, V, temperatures, T and different C60 film thickness. But we do not observe a significantly increased spin-diffusion length compared to OSV devices based on other organic semiconductors. We propose conductivity mismatch as a likely cause of the loss of spin-valve signal with increasing C60 layer thickness. There exists some disagreement in the scientific literature regarding whether OSV operate in the so-called tunneling regime or the so-called injection regime. To shed light on this question, we fabricated spin-valve devices made of organic semiconductor thin films of rubrene sandwiched between ferromagnetic cobalt and iron electrodes. Current-voltage (I-V) characteristics in Co/AlOx/rubrene/Fe junctions with a rubrene layer thickness, d, ranging from 5-50 nm, were measured, and we found two different modes of conductivity. The first mode, tunneling, occurs in relatively thin junctions, d < 15 nm, and decays exponentially with increasing rubrene thickness. We determined the tunneling decay length to be 1 nm. The tunneling mode is also characterized by a weak temperature dependence and a nearly parabolic differential conductance. The second mode, injection followed by hopping, occurs in relatively thick devices, d ≥ 15 nm, and can be identified by strongly temperature dependent, highly non-linear I-V traces that are similar to those commonly measured in organic injection devices such as OLEDs. We observed MR in devices with a rubrene thickness of 5 nm and 10 nm. Those devices are clearly in the tunneling regime. For the 15 nm device, for which the tunneling current is just barely measurable we could not observe MR. In the third project, we show that the performance of both OMAR and OSV devices very sensitively depends on whether the metallic layers are deposited by thermal evaporation or electron-beam evaporation. A strongly reduced spin diffusion length and an enhanced OMAR response can be achieved in devices fabricated by electron-beam evaporation. Then we showed that the difference must be attributed to the generation of traps resulting from the exposure of the organic layer to X-ray bremsstrahlung that is generated during the e-beam evaporation process. We also used the thermally stimulated current technique (TSC) to characterize these traps.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22161号 / 工博第4665号 / 新制||工||1728(附属図書館) / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 白石 誠司, 教授 藤田 静雄, 准教授 掛谷 一弘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23210号 / 工博第4854号 / 新制||工||1758(附属図書館) / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 白石 誠司, 教授 木本 恒暢, 教授 引原 隆士 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

La méthodologie classique pour la synthèse de matériaux à transition de spin a un certain degré d’irréproductibilité du fait de l’imprévisibilité des flux turbulents à l’intérieur du milieu réactionnel contenu dans la verrerie ordinaire de laboratoire. Pour tenter de résoudre ce problème, nous explorons la microfluidique de gouttelettes sans tensioactifs comme une nouvelle méthode d’obtention de matériaux à transition de spin.Après avoir testé divers dispositifs microfluidiques, nous avons synthétisé le MOF de type Hofmann [Fe(pz)Pt(CN)4] en combinant deux solutions de réactifs dans un canal débouchant immédiatement dans une buse de focalisation de flux. Le produit obtenu présente une réduction drastique de la taille de particule par rapport aux méthodes classiques, et affiche un comportement magnétique consistent avec les nanoparticules rapportées antérieurement.Malheureusement, du fait des hautes concentrations utilisées ici, la réaction se produit très rapidement, et le dispositif peut facilement se boucher si les flux sont modifiés ou perturbés. Pour résoudre ce problème, nous avons développé une nouvelle méthode : une substance causant un gonflement du PDMS est mélangée avec l’huile de la phase continue pour obtenir une réduction des dimensions du dispositive, et ainsi réduire le diamètre des gouttes de presque deux ordres de grandeur. / The conventional methodology to synthesize spin-crossover materials has some degree of irreproducibility due to the unpredictability of the turbulent flows in the reaction media contained in ordinary laboratory glassware. To address this issue, we explore surfactant-free droplet microfluidics as a new method to synthesize spin-crossover materials.After probing the use of different microfluidic devices, we synthesized the Hofmann type MOF [Fe(pz)Pt(CN)4] by combining two solutions with reactants into a channel that immediately reaches a flow-focusing junction. The product obtained displays a strong decrease in its particle size compared with the batch synthesis. The obtained nanoparticles display a magnetic behavior consistent with the nanoparticles reported previously.Unfortunately, under the high concentrations used here, the reaction occurs very quickly, and the device can easily clog when the flow rates are changed. This leads to difficulties when attempting to modulate the dimensions of the droplets without affecting the general performance of the device. To solve this problem, we developed a new method where a swelling agent is combined with the oil used as the continuous phase, resulting in a change in the critical dimensions of the PDMS chip and a change of the diameter of the droplets of almost two orders of magnitude.

In the past two decades, the interest in materials with strong spin-orbit coupling has attracted substantial attention because of the novel physical mechanisms they display and their potential for applications. The interface displaying large spin-orbit coupling has been recognized as a powerful platform to investigate the spin transport in ferromagnetic, antiferromagnetic, and non-magnetic materials, as well as their interfaces. Besides its rich physics, the related applications are also worth studying. The current-induced spin-orbit-torque arising from angular momentum transfer from the lattice to the spin system has substantial potential in recent state-of-art spin-orbit torque magnetic random access memory. In this dissertation, we have been interested in better understanding and characterizing the spin-orbit torque and spin Hall transport in various heterostructures of interest. We used the second harmonic method to determine the magnitude of the spin currents generation and transmission in Cu-Au alloy and Ir-Mn compound, respectively. We also characterized the device performance in selected heterostructures displaying either perpendicular MgO-based tunnel magnetoresistance or unusual surface states. Finally, we used these properties to approach spin-orbit torque magnetic random access memory through designing, fabricating, and characterizing the devices that focused on current-induced spin-orbit-torque magnetization switching.

This dissertation deals with the dynamics of interacting quantum and classical spin models and the question of whether and to which degree the dynamics of these models agree with each other. For this purpose, XXZ models are studied on different lattice geometries of finite size, ranging from one-dimensional chains and quasi-one-dimensional ladders to two-dimensional square lattices. Particular attention is paid to the high-temperature analysis of the temporal behavior of autocorrelation functions for both the local density of magnetization (spin) and energy, which are closely related to transport properties of the considered models. Due to the conservation of total energy and total magnetization, the dynamics of such densities are expected to exhibit hydrodynamic behavior for long times, which manifests itself in a power-law tail of the autocorrelation function in time. From a quantum mechanical point of view, the calculation of these autocorrelation functions requires solving the linear Schrödinger equation, while classically Hamilton’s equations of motion need to be solved. An efficient numerical pure-state approach based on the concept of typicality enables circumventing the costly numerical method of exact diagonalization and to treat quantum autocorrelation functions with up to N = 36 lattice sites in total. While, in full generality, a quantitative agreement between quantum and classical dy- namics can not be expected, contrarily, based on large-scale numerical results, it is demonstrated that the dynamics of the quantum S = 1/2 and classical spins coincide, not only qualitatively, but even quantitatively, to a remarkably high level of accuracy for all considered lattice geometries. The agreement particularly is found to be best in the case of nonintegrable quantum models (quasi-one-dimensional and two-dimensional lattice), but still satisfactory in the case of integrable chains, at least if transport properties are not dominated by the extensive number of conservation laws. Additionally, in the context of disordered spin chains, such an agreement of the dynamics is found to hold even in the presence of small values of disorder, while at strong disorder the agreement is pronounced most for larger spin quantum numbers. Finally, it is shown that a putative many-body localization transition within the one- dimensional spin chain is shifted to stronger values of disorder with increasing spin quantum number. It is concluded that classical or semiclassical simulations might provide a meaningful strategy to investigate the quantum dynamics of strongly interacting quantum spin models, even if the spin quantum number is small and far from the classical limit.