Thesis (Ph.D. (Natural and Agricultural Science)) -- University of Pretoria, 2009. / Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:23:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-06-28Bitstream added on 2014-06-13T19:50:16Z : No. of bitstreams: 1 simoes_rp_me_bauru.pdf: 20203043 bytes, checksum: b1791cdffb4735eb5cba45bb735dc2f7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O estudo dos regimes dinâmicos de vórtices em supercondutores do tipo II tem atraído grande interesse do ponto de vista teórico e experimental, por um lado pela riqueza de comportamentos que é apresentado e, por outro, pela compreensão dos mecanismos de pinning, o qual é utilizado para aumentar e manter a densidade de corrente crítica, permitindo seu uso em aplicações práticas. Usando simulações de dinâmica molecular, analisamos os efeitos de pinning artificiais na dinâmica de vórtices em filmes finos supercondutores do tipo II. Além da distribuição aleatória de centros de pinning, dois tipos de arranjos periódicos foram considerados: hexagonal e kagomé. Para o arranjo kagomé analisamos a dinâmica para a força externa aplicada nas direções transversal e longitudinal em relação à simetria da rede. Em cada caso são observados comportamentos dinâmicos distintos da rede de vórtices, uma vez que existem simetrias diferentes para cada direção. Diferentemente dos resultados obtidos para a distribuição aleatória e hexagonal de pinnings, para o arranjo de kagomé, a rede de vórtices apresenta uma dinâmica e um segundo pico na resistência diferencial ainda não descritos na literatura. Quando a força é aplicada na direção longitudinal, são observados regimes dinâmicos complexos da rede de vórtices. Para esse caso, além dos regimes ordenados típicos de redes periódicas de pinnings, os vórtices se movem em canais desordenados quando a corrente de transporte é aumentada, lembrando o regime smectic visto em simulações com pinning aleatório. Subsequentemente, para altas correntes, os vórtices atingem um regime dinâmico onde eles novamente se movem em canais bem definidos, revelando uma ordem transversal. Para o arranjo hexagonal, os vórtices sempre se movem em linhas retas. Apresentamos também um estudo da densidade de corrente crítica para diferentes valores de densidade de vórtices. / The study of current-driven vortex lattices in type II superconductors has attracted a great interest from both experimental and theoretical point of view, on the one side for the riches of behaviors that is showed and, otherwise, for the comprehension of pinning mechanisms, which has been used to increase and to maintain the critical current density, to allow their use in practical applications. Using molecular dynamics simulations, we analyze the effects of artificial pinning on the vortex dynamics of type II superconductors thin films. Yonder random distribution of pinning centers, two types of periodic pinning arrays are considered: the hexagonal and kagomé. For the kagomé array, we analyze the dynamics for the applied external force in the transversal and longitudinal directions to the lattice symmetry. For each case are observed different dynamical behaviors of vortex lattice, once there are different symmetries for each direction. Differently than the results obtained for the random and hexagonal distribution of pinnings, for the kagomé array, the vortex lattice show a dynamic and a second peak in the differential resistance still not reported in the literature. When the force is applied in the longitudinal direction, the dynamical behavior of vortices is much more complex. For this case, yonder the ordered regimes, typically observed in systems with periodic pinning, the vortices moving in disordered channels when the transport current is increased, resembling the smetic dynamical regime that was found in simulations for random pinning distributions. Subsequently, for high currents, the vortices reach dynamical regime where they move in well defined channels again, revealing transversal ordering. For the hexagonal array, the vortices always move in straight trajectories. We also show a study of critical current density for different values of vortex density. For all densities, the hexagonal pinning network shows higher critical currents.

Submitted by Lucas Cesar Gomes Squillante null (lucasquillante@hotmail.com) on 2018-01-19T17:39:44Z No. of bitstreams: 1 Dissertação de Mestrado Lucas Cesar Gomes Squillante.pdf: 13112928 bytes, checksum: b4a4e7a0bc1cbdc48db3b829714e912d (MD5) / Approved for entry into archive by Ana Paula Santulo Custódio de Medeiros null (asantulo@rc.unesp.br) on 2018-01-22T13:15:43Z (GMT) No. of bitstreams: 1 squillante_lcg_me_rcla.pdf: 13113103 bytes, checksum: ee63e961b931fa78df69438fc268b5f2 (MD5) / Made available in DSpace on 2018-01-22T13:15:43Z (GMT). No. of bitstreams: 1 squillante_lcg_me_rcla.pdf: 13113103 bytes, checksum: ee63e961b931fa78df69438fc268b5f2 (MD5) Previous issue date: 2017-11-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O fenômeno da supercondutividade atualmente um dos mais relevantes tópicos na Física da Matéria Condensada, tornando os sistemas fortemente correlacionados um tópico de grande interesse devido à possibilidade de estudar os aspectos fundamentas da interação elétron-elétron, que são o âmago da supercondutividade. Desta forma, a classe de condutores moleculares (TMTTF)2X (onde TMTTF é tetrametiltetratiafuvaleno e X é um contra-ânion) desempenha um papel sistemático e fundamental no estudo de tais aspectos de correlação. Nesta tese de mestrado, os materiais de interesse foram o (TMTTF)2PF6-H12 e o (TMTTF)2PF6-D12, onde uma anomalia na constante dielétrica diferente para os dois sais foi observada na transição ferroelétrica de Mott-Hubbard através de medidas de constante dielétrica quasi-estática no eixo c* (contribuição iônica) e o comportamento tipo relaxor da variante hidrogenada foi analisado com base na teoria de campo médio. Uma revisão de transições de fase clássicas e quânticas também foi realizada com o objetivo de estudar o chamado efeito magneto-calórico para o modelo do paramagneto de Brillouin (o parâmetro de Grüneisen magnético), que é uma grandeza Física única e poderosa para detectar experimentalmente uma transição de fase quântica induzida por campo magnético em um sistema real. Ainda, um estudo comparativo entre as fases delta (hexagonal) e delta' (tetragonal) da liga binária FeSe1-x foi realizado e monocristais foram sintetizados utilizando o método de síntese de estado sólido visando atingir a fase delta. / The phenomenon of superconductivity is currently one of the most relevant topics in Solid State Physics, making strongly correlated systems a very highattractive topic due to the possibility of studying the fundamental aspects of the electron-electron interaction that are the core of superconductivity. Thus, the class of molecular conductors (TMTTF)2X (where TMTTF is tetramethyltetrathiafuvalene and X is a counter-anion) plays a systematic and fundamental role to study such correlation aspects. In this Master Thesis, the materials of interest were the (TMTTF)2PF6-H12 and (TMTTF)2PF6-D12, where a different dielectric anomaly at the Mott-Hubbard ferroelectric transition was observed for the two salts and the relaxor behavior of the hydrogenated variant was analysed based on the mean-field theory. A review of classical and quantum phase transitions was performed aiming to study the so-called magneto-caloric effect (the magnetic Grüneisen parameter) for the Brillouin paramagnet model, which is a powerful and unique physical quantity to experimentally detect a quantum phase transition induced by magnetic field in a real system. Also, a comparative study between the (hexagonal) and (tetragonal) phases of the binary alloy FeSe1-x was performed and single-crystals were synthesized employing the solid-state reaction method in order to achieve the phase.

In his programmatic article More Is Different (1972), Nobel laureate P. W. Anderson captured the fundamental interest in quantum matter in a nutshell. The central motive in this field is emergence. In the inaugural volume of the homonymous journal, J. Goldstein defined this as "the arising of novel and coherent structures, patterns and properties during the process of self-organization in complex systems". Famously, the idea that the "the whole is greater than the sum of its parts" goes back to Aristotle's metaphysics, and it has served as a stimulating concept in 19th century biology, economics and philosophy. The study of emergence in condensed matter physics is unique in that the underlying complex systems are sufficiently "simple" to be modelled from first principles. Notably, the emergent phenomena discovered in this field, such as high-temperature superconductivity, giant magnetoresistance, and strong permanent magnetism have had an enormous impact on technology, and thus, society. Historically, there has been a distinction between materials with localized, strongly interacting (or correlated) electrons - and non-interacting, itinerant electronic states. In the last decade, several new states of matter have been discovered, which emerge not from correlations, but from peculiar symmetries (or topology) of itinerant electronic states. The term quantum materials has therefore become popular to subsume these two strands of condensed matter physics: Electronic correlations and topology. In this thesis, I report investigations of four quantum materials which each illustrate present key interests in the field: The mechanism of high temperature superconductivity, the search for materials that combine both electronic correlations and non-trivial topology and novel emergent phenomena that arise from the synergy of electronic correlations and a strong coupling of spin- and orbital degrees of freedom. The common factor and potential key to understanding these materials is magnetism. My experimental work is focused on neutron and x-ray scattering techniques, which are able to determine both order and dynamics of magnetic states at the atomic scale. I illustrate the full scope of these methods with experimental studies at neutron and synchrotron radiation facilities. This includes both diffraction and spectroscopy, of either single- or polycrystalline samples. My in-depth analysis of each dataset is aided by structural, magnetic and charge transport experiments. Thus, I provide a quantitative characterization of magnetic fluctuations in an iron-based superconductor and in two Dirac materials, and determine the magnetic order in a Dirac semimetal candidate and a complex oxide. As a whole, these results demonstrate the elegant complementarity of modern scattering techniques. Although such methods have a venerable history, they are presently developing at a rapid pace. Several results of this thesis have only been enabled by very recent instrumental advances.

Orientador: Edson Sardella / Banca: Rafael Zadorosny / Banca: Paulo Noronha Lisboa Filho / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: É notável o desenvolvimento atual da Ciência e Tecnologia relacionada aos materiais supercondutores. Exemplos de utilização deste tipo de material, são o armazenamento de energia em forma de supercondutores, trens do tipo Maglev, cujo uso das supercorrentes também proporciona a geração de altos valores de campos magnético que podem proporcionar levitação e propulsão. Aplicações desta natureza, dentre outras, requerem uma profunda compreensão do comportamento das propriedades físicas fundamentais dos supercondutores, tnato do ponto de vista macroscópico. Como exemplo, podemos citar a formação de rede de vórtices em materiais supercondutores na presença de campos magnéticos aplicados e/ou de correntes de transporte, cujas magnitudes, quando ultrapassam determinados valores críticos, permitem a entrada quantizada de fluxo magnético. Com relação aos métodos utilizados neste trabalho, estudamos o comportamento e as características de um material de dimensões mesoscópicas em formato de dispositivo supercondutor de interferência quântica - "SQUID", um tipo de magnetômetro muito sensível, capaz de realizar medidas de campos magnéticos muito tênues - usando um algoritmo de simulação computacional. A simulação basicamente atua no sentido de se aplicar campos magnéticos em passos d tempo determinados - a temperatura fixa - ao material modelado, o que permite o estudo das características deste tipo de material por meio dos dados de saída gerados pelos simulador, os quais permitem a construção de gráficos para estudo do comportamento do parâmetro de ordem, densidades de corrente, formação de vórtices, entre outros parâmetros relacionados. Assim, fazems uma revisão das teorias fenomenológicas e desenvolvemos uma algorítimo de solução numérica das equações envolvidas, as quais não possuem solução exata. Em seguida usamos a tecnologia CUDA com a linguagem C para implementar este algoritmo e... / Abstract: It is remarkable the current development of science and technology related to superconducting materials. Examples of using this type of material, such as storage of energy as supercurrents, the Maglev-type trains, which also provides use of supercurrents generating high values of magnetic field that can provide levitation and propulsion. Aplications of this nature, among others, require a deep understanding of the bahavior of the fundamental physical properties of superconductors, both from the macroscopic and microscopic point of view. As one example, the formation of vortex lattice in superconducting materials in the presence of applied magnetic fields and/or transport chains whose magnitudes when they exceed certain critical values allow the quantized magnetic flux entrance. With respect to the methods used in this work, we studied the behavior and characteristics of a material with mesoscopic dimensions in a geometry of a superconducting quantum interference device - "SQUID". Such device is a kind of very sensitive magnetometer, able to perform very faint magnetic fields measures - using a computer simulation algorithm. The simulation basically acts to apply magnetic fields at certain time steps - with fixed temperature - to the modeled material, allowing the study of the characteristics of this type of material by means of output data generated by the simulator, which allows the construction of graphs to study the order parameter behavior, current densities, vortex formation, and other related parameters. Thus, we review the phenomenological theories and developed a numerical solution algorithm of the involved equations, which have no exact solution. Then we use the CUDA technology with the C language to implement this algorithm and apply it to solving the problem of a SQUID with a small construction. Finally, the graphics are constructed using the data generated by the simulator for analysis and interprettion of the behavior of the... / Mestre

Made available in DSpace on 2016-01-13T13:27:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-28. Added 1 bitstream(s) on 2016-01-13T13:33:09Z : No. of bitstreams: 1 000854891.pdf: 3880959 bytes, checksum: de544c0ed2201162f13b76fa4ab52356 (MD5) / É notável o desenvolvimento atual da Ciência e Tecnologia relacionada aos materiais supercondutores. Exemplos de utilização deste tipo de material, são o armazenamento de energia em forma de supercondutores, trens do tipo Maglev, cujo uso das supercorrentes também proporciona a geração de altos valores de campos magnético que podem proporcionar levitação e propulsão. Aplicações desta natureza, dentre outras, requerem uma profunda compreensão do comportamento das propriedades físicas fundamentais dos supercondutores, tnato do ponto de vista macroscópico. Como exemplo, podemos citar a formação de rede de vórtices em materiais supercondutores na presença de campos magnéticos aplicados e/ou de correntes de transporte, cujas magnitudes, quando ultrapassam determinados valores críticos, permitem a entrada quantizada de fluxo magnético. Com relação aos métodos utilizados neste trabalho, estudamos o comportamento e as características de um material de dimensões mesoscópicas em formato de dispositivo supercondutor de interferência quântica - SQUID, um tipo de magnetômetro muito sensível, capaz de realizar medidas de campos magnéticos muito tênues - usando um algoritmo de simulação computacional. A simulação basicamente atua no sentido de se aplicar campos magnéticos em passos d tempo determinados - a temperatura fixa - ao material modelado, o que permite o estudo das características deste tipo de material por meio dos dados de saída gerados pelos simulador, os quais permitem a construção de gráficos para estudo do comportamento do parâmetro de ordem, densidades de corrente, formação de vórtices, entre outros parâmetros relacionados. Assim, fazems uma revisão das teorias fenomenológicas e desenvolvemos uma algorítimo de solução numérica das equações envolvidas, as quais não possuem solução exata. Em seguida usamos a tecnologia CUDA com a linguagem C para implementar este algoritmo e... / It is remarkable the current development of science and technology related to superconducting materials. Examples of using this type of material, such as storage of energy as supercurrents, the Maglev-type trains, which also provides use of supercurrents generating high values of magnetic field that can provide levitation and propulsion. Aplications of this nature, among others, require a deep understanding of the bahavior of the fundamental physical properties of superconductors, both from the macroscopic and microscopic point of view. As one example, the formation of vortex lattice in superconducting materials in the presence of applied magnetic fields and/or transport chains whose magnitudes when they exceed certain critical values allow the quantized magnetic flux entrance. With respect to the methods used in this work, we studied the behavior and characteristics of a material with mesoscopic dimensions in a geometry of a superconducting quantum interference device - SQUID. Such device is a kind of very sensitive magnetometer, able to perform very faint magnetic fields measures - using a computer simulation algorithm. The simulation basically acts to apply magnetic fields at certain time steps - with fixed temperature - to the modeled material, allowing the study of the characteristics of this type of material by means of output data generated by the simulator, which allows the construction of graphs to study the order parameter behavior, current densities, vortex formation, and other related parameters. Thus, we review the phenomenological theories and developed a numerical solution algorithm of the involved equations, which have no exact solution. Then we use the CUDA technology with the C language to implement this algorithm and apply it to solving the problem of a SQUID with a small construction. Finally, the graphics are constructed using the data generated by the simulator for analysis and interprettion of the behavior of the...

Made available in DSpace on 2015-09-17T15:24:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-07. Added 1 bitstream(s) on 2015-09-17T15:47:44Z : No. of bitstreams: 1 000847800.pdf: 5217061 bytes, checksum: d81cf4ffb3e71ef7d7384c5a055cd122 (MD5) / Neste trabalho será apresentado o estudo da preparação de filmes supercondutores do sistema BiSrCaCuO. A partir de um pó adquirido comercialmente com composição nominal Bi 1.8 Pb 0.4 Sr 2 CaCu 2 O x, foi preparado um filme tratado termicamente a 800oC (B12CM800) por 7 minutos. Outro filme usando um pó de composição semelhante, produzido pelo método de Pechini modificado para este fim, foi preparado e tratado termicamente a 810oC (B12SM810) durante 7 minutos em forno de micro-ondas. Também foi produzido pelo método de Pechini, um pó de composição nominal Bi 1.8 Pb 0.4 Sr 2 Ca 2 Cu 3 O x, o qual foi utilizado na preparação de outros três filmes tratados termicamente a 780oC (B23SM780), 810oC (B23SM810) e 840oC (B23SM840), durante 10, 5 e 5 minutos, respectivamente. Os filmes foram crescidos sobre um substrato cristalino de LaAlO 3 (100) e tratados termicamente em um forno de micro-ondas doméstico (2.45 GHz, 1200 W) devidamente adaptado para esta finalidade. As propriedades estruturais foram estudadas utilizando as técnicas de difração de raios-X, DRX, e a microscopia eletrônica de varredura, MEV. A técnica de DRX indicou a formação da fase 2212 nos filmes B12CM800, B12SM810, B23SM780 e B23SM810, assim como o surgimento da fase 2201 e de fases agregadas, Ca 2 PbO 4 e Bi 2 CaO 4 . O filme B23SM840 apresentou, além das fases 2212 e secundárias, também a fase 2223. A técnica de MEV indicou a formação de estruturas na forma de placas crescidas em camadas, típicas do material em estudo, além da formação de estruturas superficiais ricas em Ca em todos os filmes, exceto para o B23SM840, que apresentou apenas a formação de placas. Utilizando a técnica de energia dispersiva de raios-X, EDX, foi possível verificar uma provável composição nominal dos filmes correspondente à fase 2223 para o filme B23SM840 e 2212 para os demais. As medidas elétricas foram feitas utilizando o método de quatro pontas, possibilitando... / In the present work, the preparation of superconducting films of the BSCCO system will be presented. From a commercially available powder with nominal composition Bi 1.8 Pb 0.4 Sr 2 CaCu 2 O x, a film was prepared and heat-treated at 800°C (B12CM800). Powder with a similar composition was produced by the Pechini method modified for this purpose and a film heat-treated at 810oC (B12SM810) was them prepared. Also produced by Pechini method, a powder with nominal composition Bi 1.8 Pb 0.4 Sr 2 Ca 2 Cu 3 O x was used to prepare other three films thermally treated at 780oC (B23SM780), 810oC (B23SM810) and 840oC (B23SM840). The films were grown on crystalline substrates of LaAlO 3 (100) and thermally treated in a domestic microwave oven (2.45 GHz, 1200 W) adapted suitably for this purpose. The structural properties were studied using X-ray diffraction techniques, XRD, and scanning electron microscopy, SEM. The XRD technique indicated the formation of the 2212 phase in the B12CM800, B12SM810, B23SM780 and B23SM810 films, as well as the appearance of the 2201 phase and the following secondary phases: Ca 2 PbO 4 and Bi 2 CaO 4 . The film B23SM840 also indicated the formation of 2223 besides the 2212 phase and aggregates. The SEM technique presented the formation of structures with plate shape, typical of this material, and a superficial formation of structures rich in Ca on all the films, except for the B23SM840 film, which showed only the formation of plates. The energy dispersive X-rays technique, EDX, was carried out to verify a likely nominal composition of the films corresponding to 2223 phase for the B23SM840 film and 2212 phase for the others. The electrical measurements were made using the four-probe method, enabling the identification of the critical transition temperatures, T c, T c-onset, T c- midpoint and T c-offset, also the determination of the critical current density, J c . All films shown a characteristic T c of the 2212 ...

The novel grain refiners developed in this research could be broadly classified into borides and carbides. The motive behind choosing MgB2, AlB2 and their master alloys Mg-MgB2 and Mg-AlB2 as the grain refiners was driven by the crystallographic matching of the hexagonal borides with the magnesium crystal structure. Apart from this lightweight borides, denser borides such as CrB and WB have also shown excellent grain refinement in AZ91, AM50 and AZ31 alloys. It is suggested that the grain refinement effect in the magnesium alloys could be improved through a combined addition of bismuth along with the boride. The carbon based grain refiners were also explored as they are well-established for the grain refinement of aluminium containing magnesium alloys. The new carbon based grain refiners identified through this research are B4C, Mg-B4C, Mg-3Ti-1C. Magnesium matrix was chosen for the development of each of these master alloys to eliminate any impurity contamination during the grain refiner addition to the magnesium melt. The pressureless melt infiltration techniques was involved in the development of Mg-MgB2, Mg-AlB2 and Mg-B4C while, the ‘halide salt route’ was adopted for producing Mg-3Ti-1C master alloys. The application of ultrasonic cavitation for the development of a new Al-1.5B-2C master alloy was shown to be effective for a homogenous distribution of the intermetallic phases in the form of Al3BC. The potential heterogeneous nucleating sites proposed in the commercial aluminium containing magnesium alloys are MgB2 for Mg-MgB2 master alloy; Mg1-xAlxB2 (0.10 < x < 0.18) for AlB2 grain refiner; MgB2C2 for B4C grain refiner; CrB and WB for their individual powder additions respectively; Ti2AlC for Mg-3Ti-1C master alloy; Al3BC and Al4C3 for the Al-1.5B-2C master alloy.

L'auteur n'a pas fourni de résumé en français / The superconductivity had been thought to be incompatible with the magnetism, because the former originates from the weak attractive leading to the formation of Cooper pairs, whereas the latter is based on the strong Coulomb repulsive force, leading also to strong electronic correlations. Unconventional superconductors,which include heavy fermion systems, high-Tc cuprates, organic superconductors, and iron-pnictides, is a major topic of condensed matter physics. In all these systems, it has been understood that magnetism can even plays an important role for the pairing mechanism, so that both phenomena can coexist and even favour each other.Our target is on heavy fermion systems, namely uranium and rare earth compounds, where the 5f or 4f electrons which have a dual nature (itinerant/localized), play an important role. More precisely, we will focus on the ferromagnetic superconductors and their quantum criticality. In this field, new materials open new frontiers of research. The student will participate in this stream. He will learn and develop the fundamental crystal growth techniques, such as Czochralski, flux, and Bridgeman method. Since high quality single crystals are essential to elucidate the superconducting properties, a lot of efforts will be devoted to improve the quality of the samples. The next target is the quantum oscillation measurements, which allow a detailed microscopic observation of the heavy electronic state and of the topology of the Fermi surface. They require both very low temperature and high fields, like the study of the field induced superconducting phases in these compounds (like URhGe or UCoGe). The student will perform the measurements under extreme conditions, namely high fields up to 15T in SPSMS, or up to 30T in LNCMI, at low temperatures down to 30 mK, and high pressure up to 3 GPa.From the educational point of view, it is ideal that the student starts to synthesize a material, characterizes it, performs the low temperature measurements by him/herself throughout the PhD period, and get used to the exciting measurements under extreme conditions in a large scale facility like the LNCMI. Such a wide spectrum is rather rare in Europe, but our group („SPSMS/LNCMI) can provide such a unique opportunity, helping the student to become an independent researcher. It should be noted that the experiments in SPSMS and LNCMI are quite complementary each other. For quantum oscillation study, high fields, low temperatures and high quality singles are inevitably important. In general, the precise measurements at high fields up to 15T would be enough in order to determine the Fermi surface topology and the effective mass, which canbe done in SPSMS. However, the specific case, such as Lifshitz transition, field induced quantum critical phenomena, requires higher fields than 15T, which can be achieved by the resistive magnet in LNCMI.This project is supported by the ANR (CORMAT, SINUS) and the ERC starting grant “NewHeavyFermion”.Recently in SPSMS we purchased a top-loading dilution refrigerator for the quantum oscillation measurements, and started the installation. By the end of this summer, hopefully we detect the first de Haas-van Alphen signal at high fields up to 15T and at temperatures down to 30mK. Furthermore, we started to install the flux crystal growth equipment this month, involving the reconstruction of the room for the safe treatment of uranium compounds.

Made available in DSpace on 2014-10-09T12:36:38Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:09Z (GMT). No. of bitstreams: 1 04226.pdf: 1346289 bytes, checksum: ae51647be934d5e52ce7e2787d3ee5b5 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP