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Дисертації з теми "Fe–W"

Автор: Grafiati
Опубліковано: 30 травня 2022
Оновлено: 31 травня 2022

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1

Karakurkchi, A. V., M. V. Ved, N. D. Sakhnenko, I. Yu Yermolenko, and S. I. Zyubanova. "Electroplating and functional properties of amorphous Fe-Mo(W) and Fe-Mo-W coatings." Thesis, Институт химии растворов им. Г. А. Крестова РАН, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22618.

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2

Григор'єва, Світлана Вікторовна, та Олександр Євгенович Бармін. "Сегрегаційні явища в сплавах Fe−W". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/43755.

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3

Бармин, Александр Евгеньевич. "Тонкая структура вакуумных конденсатов Fe–W". Thesis, НТУ "ХПИ", 2011. http://repository.kpi.kharkov.ua/handle/KhPI-Press/14372.

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4

Бармин, Александр Евгеньевич, Александр Иванович Ильинский, Анатолий Иванович Зубков та Мария Александровна Глущенко. "Термическая стабильность вакуумных нанокомпозитов Fe-W". Thesis, Национальный научный центр "Харьковский физико-технический институт", 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/14366.

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5

Бармин, Александр Евгеньевич. "Особенности структуры вакуумных конденсатов Fe-W". Thesis, НТУ "ХПИ", 2012. http://repository.kpi.kharkov.ua/handle/KhPI-Press/14371.

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6

Бармин, Александр Евгеньевич. "Диспергирование зеренной структуры cплавов Fe–W полученных в вакууме". Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/36750.

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7

Mc, Grath Oran F. K. "Structural and magnetic properties of epitaxial W/Fe/W and Gd/Fe films grown by pulsed laser deposition." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10209.

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Анотація:
Le but de cette these est d'etudier les proprietes structurales et magnetiques des couches epitaxiees de w/fe/w et gd/fe elaborees par depot laser pulse. La technique de depot laser pulse est presentee dans le premier chapitre. La croissance des couches minces est discutee dans le deuxieme chapitre puis l'analyse des proprietes structurales des couches elaborees est presentee dans le troisieme chapitre. Une revue des proprietes magnetiques des couches ultra-minces, telle que le moment magnetique, l'anisotropie et les excitations thermiques est presentee dans le quatrieme chapitre. La determination experimentale de ces proprietes magnetiques dans les couches de w/fe/w est discutee dans le cinquieme chapitre. Le couplage interfacial dans les couches de gd/fe est analyse dans le dernier chapitre
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8

Бармин, Александр Евгеньевич. "Сегрегационные явления в вакуумных конденсатах Fe-W". Thesis, Институт металлургии и материаловедения им. А. А. Байкова РАН, 2011. http://repository.kpi.kharkov.ua/handle/KhPI-Press/14359.

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9

Plantin, Pascale. "Dépôts multicouches Fe/W sur substrat de Fe par pulvérisation magnétron D. C." Phd thesis, Université d'Orléans, 2006. http://tel.archives-ouvertes.fr/tel-00123902.

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Анотація:
Le masque des tubes cathodiques est un élément déterminant pour la qualité de l'image d'un téléviseur. Le masque est une grille de fer (Fe) oxydée sous forme de magnétite (Fe3O4). Le bombardement électronique subi par le masque génère des gradients de température. Il s'en suit une déformation du masque. L'image perd alors en contraste et en brillance. L'étude a porté sur la détermination, l'élaboration et la caractérisation d'une couche mince limitant ce gradient de température. Le matériau choisi pour cette couche protectrice est le tungstène (W) associé au fer (Fe) sous sa forme oxyde de fer : Fe3O4. Le tungstène est un matériau réfractaire avec un haut coefficient de rétrodiffusion des électrons. De plus, la magnétite possède un bon coefficient d'émissivité thermique. Ces deux propriétés sont essentielles pour éviter la déformation due au gradient de température. L'étude a porté sur les dépôts de couches minces (système bicouche) Fe3O4/W mais aussi alliage Fe-W sur substrat de Fe (matériau du masque). Les dépôts ont été réalisés par pulvérisation magnétron au moyen d'un générateur à décharge continue (pulsée ou non) avec ou sans l'assistance d'un plasma auxiliaire radiofréquence créé par une antenne interne. Pour tenter d'obtenir une couche mince de Fe3O4, nous avons étudié les oxydations ex-situ après dépôts ainsi qu'in-situ pendant ou après dépôts (en les comparant entre elles). Les caractérisations ont concerné l'étude de la structure (microscopie électronique, diffraction des rayons X), l'adhérence (test scotch et diffraction X sous traction), la composition (Spectroscopie de Rétrodiffusion Rutherford et Analyse par Réaction Nucléaire) et la mesure des propriétés optiques infrarouge et thermiques.
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10

Kubetzka, André. "Spinpolarisierte Rastertunnelmikroskopie an magnetischen Nanostrukturen: Fe-W(110)." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965752569.

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11

Mireles, Hector Córdova. "Step induced magnetic anisptropy of Fe/W(100) /." Digital version:, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p9992874.

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12

Бармин, Александр Евгеньевич. "О степени однородности структуры вакуумных конденсатов Fe-W". Thesis, Институт металлургии и материаловедения им. А. А. Байкова РАН, 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20335.

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13

Бармин, Александр Евгеньевич, Александр Иванович Ильинский та Анатолий Иванович Зубков. "Термическая стабильность структуры и свойств нанокомпозитов Fe-W". Thesis, Национальный научный центр "Харьковский физико-технический институт", 2011. http://repository.kpi.kharkov.ua/handle/KhPI-Press/14357.

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14

Capel, Hollie. "Deposition, microstructure & properties of Co-W & Co-W-Fe alloys." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404038.

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15

Sanches, Luciana Schmidlin. "Estudo da eletrodeposição de ligas Fe-Ni-Mo e Fe-Ni-W com aplicações tecnológicas." Universidade Federal de São Carlos, 2008. https://repositorio.ufscar.br/handle/ufscar/6138.

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Анотація:
Made available in DSpace on 2016-06-02T20:34:15Z (GMT). No. of bitstreams: 1 2101.pdf: 5040503 bytes, checksum: 4bcdc53ff51b570fabdaefe96dd60f7c (MD5) Previous issue date: 2008-01-16
Universidade Federal de Sao Carlos
This paper reports a study on the electrodeposition of alloys Fe-Ni-Mo and Ni-Fe-W, the physical characterization and application in the reaction of hydrogen (RDH). The process of deposition and dissolution of alloys were studied by cyclical voltametric to determine the region of potential characteristic of the deposition and dissolution. The electrode used in the voltametric studies was platinum disc in solution of sodium citrate 0.2 mol / L at pH 5.0 and 8.0 on the grounds of concentration of ions Fe:Ni:Mo and Fe:Ni:W, 1:1:1, 1:10:1, 10:1:1, 10:10:1 and 10:10:2. The results of the voltametric analysis indicated the presence of well-defined peaks of dissolution for the alloy at high concentrations of Fe and Ni. Analysis of MEV, EDX, XPS and AA were used to characterize the alloys at pH 5.0 and 8.0. The morphology of materials containing Mo and W present the general structure globular, with the exception of alloy Fe-Ni-W obtained in the ratio 10:10:1 and pH 8 which is flat. Change occurs not linear in the size of a grain of these materials with the variation in the pH. These results of EDX indicated the presence of a smaller amount of oxygen in materials obtained in the base, and these were the deposits that had best results for RDH. The alloy with 80.6% Fe, 14.9% for Ni and 4.5% of W was presented to the best catalytic activity to RDH and a overpotential to -135 mA cm-2 of -142 mV. The XPS analysis showed that for alloys Fe-Ni-W deposited in the base occurs deposition of W (0), and the alloys Fe-Ni-Mo the ions molybdenum are reduced first to a mixture of oxides of molybdenum (IV ) and (V), forming an intermediary, which is thereafter reduced to Mo in metallic alloys. The analysis of AA alloys showed that the Fe-Ni-Mo electrodeposited in acidic environment have increased thickness which alloys in the base, being Fe-Ni-Mo obtained in acidic average thickness of 28.5 m to alloy Fe-Ni-Mo , and a thickness average of 13.3 m in the basics.
Este trabalho relata um estudo sobre a eletrodeposição de ligas de Fe-Ni-Mo e Fe-Ni-W, sua caracterização física e aplicação na reação de desprendimento de hidrogênio (RDH). O processo de deposição e dissolução das ligas foi estudado por voltametria cíclica para se determinar à região de potencial característico da deposição e dissolução. O eletrodo utilizado nos estudos voltamétricos foi de disco de platina em solução de citrato de sódio 0,2 mol/l em pH 5,0 e 8,0 nas razões de concentração dos íons Fe:Ni:Mo e Fe:Ni:W de 1:1:1, 1:10:1, 10:1:1, 10:10:1 e 10:10:2. Os resultados das análises voltamétricas indicaram a presença de picos de dissolução bem definidos para as ligas em altas concentrações de Fe e Ni. Análises de MEV, EDX, XPS e AA foram utilizadas para caracterizar as ligas eletrodepositadas em pH 5,0 e 8,0. A morfologia dos materiais contendo Mo e W apresentam em geral estrutura globular, com exceção da liga Fe-Ni-W obtida na razão 10:10:1 e pH 8 que é lisa. Ocorre mudança não linear, no tamanho de grão destes materiais com a variação do pH de eletrodeposição. Os resultados de EDX indicaram a presença de uma menor quantidade de oxigênio nos materiais obtidos em meio básico, e estes foram os depósitos que apresentaram melhores resultados para RDH. A liga contendo 80,6 % de Fe, 14,9% de Ni e 4,5 % de W, foi a que apresentou a melhor atividade catalítica para RDH, tendo um sobrepotencial a -135 mA cm-2 de -142 mV As análises de XPS mostraram que para as ligas Fe-Ni-W depositadas em meio básico ocorre deposição de W (0), e para as ligas Fe-Ni-Mo que os íons molibdatos são reduzidos primeiramente a uma mistura de óxidos de molibdênio (IV) e (V), formando um intermediário, que subseqüente é reduzido a Mo metálico nas ligas. As análises de AA mostraram que as ligas Fe-Ni-Mo eletrodepositadas em meio ácido apresentam maior espessura que ligas eletrodepositadas em meio básico, sendo uma espessura média de 28,5 m para liga Fe-Ni-Mo eletrodepositada em meio ácido, e uma espessura média de 13,3 m para liga Fe-Ni-Mo eletrodepositada em meio básico.
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16

Бармин, Александр Евгеньевич. "Влияние вольфрама на разнозернситость структуры вакуумных конденсатов Fe-W". Thesis, НТУ "ХПИ", 2015. http://repository.kpi.kharkov.ua/handle/KhPI-Press/20324.

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17

West, Connor M. "Continuum Modeling of the Densification of W-Ni-Fe during Selective Laser Sintering." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1577.

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Анотація:
The purpose of this thesis is to effectively model the time history of the temperature distribution during the selective laser sintering process and use this information to investigate the resulting relative density. The temperature is a critical parameter of the process because it directly effects the overall quality of the part. First, an efficient, affordable, and reliable simulation was developed within the finite element software, Abaqus. Next, the results from the simulations were compared to the experimental results performed by Wang et al. (2016). The FEA model consisted of a 3 layer simulation. Multiple simulations at various laser recipes were conducted using W-Ni-Fe as the powder material. The P/v (laser power/scanning speed) was plotted against the resulting total time above the melting temperature for various simulation. It was concluded that a linear relationship exists between the P/v parameters used in the laser recipe and the resulting time above the melting temperature. The average R2 values for the W-Ni-Fe simulations for layer 1, 2, 3 were 0.962, 0.950, and 0.939, respectively. Additionally, the experimental results from the Wang et al. (2016) study confirmed that a linear relationship is present. Thus, it can be concluded that the P/v parameters used within the laser recipe has a direct relation to the resulting relative density of the SLS part.
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18

Lorenzon-Gaillot, Chantal. "Fragilité interfaciale des alliages lourds W-Ni-Fe élaborés par frittage en phase liquide." Grenoble INPG, 1993. http://www.theses.fr/1993INPG4204.

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Анотація:
Apres avoir detaille les mecanismes connus et les diverses influences des parametres d'elaboration, nous avons catalogue cinq types de fragilisation: porosite, teneur en hydrogene, contraintes interfaciales, segregation ou precipitation d'impuretes ainsi que leur degre d'independance. Ces indications nous ont permis d'etablir un plan de caracterisation comprenant: une etude du comportement mecanique, une etude microstructurale, une caracterisation chimique. L'ensemble de ces etudes a conduit a la definition de la parfaite homogeneite macroscopique entre les alliages dits fragiles et les alliages de reference. Ce premier resultat a oriente nos recherches vers l'etat chimique des interfaces des alliages. La spectrometrie auger a montre la presence de phosphore et de soufre dans les surfaces de rupture; bien que les teneurs globales de ces elements dans les alliages soient inferieures a s<6 ppm p<25 ppm. L'etude quantitative de ce phenomene, par spectrometrie auger a necessite un gros effort pour ameliorer le depouillement des spectres. Nous avons ainsi mis au point une nouvelle methodologie de calibration d'un systeme complexe (w, fe, ni, p, s) a partir d'etalons polyconstitues. Les mecanismes mis en jeu ont ete etudies a partir de la similitude des phenomenes en segregations aux joints de grains et a la surface externe. Nous avons donc suivi l'evolution des especes chimiques en surface au long de cycles thermiques industriels. Le soufre segrege generalement en premier puis est partiellement remplace par le phosphore aux temperatures superieures. Le refroidissement accentue ce phenomene et ne provoque pas de retour du soufre ce qui montre que l'evolution n'est pas reversible. Pour conclure cette etude, nous avons fait segreger le soufre ou le phosphore aux interfaces a l'aide de cycles appropries. Ces experiences ont permis de montrer le role fragilisant du soufre a des teneurs extremement faibles de 3 a 10% at et l'attenuation de cette fragilisation en presence de phosphore
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19

Хоменко, Любов Григорівна, Любовь Григорьевна Хоменко та Ljubov Grigorіvna Khomenko. "Структурні перетворення в швидкозагартованих бінарних та квазібінарних системах на основі Fe, Ti та W". Thesis, Техн. центр НАН Укр, 2012. http://essuir.sumdu.edu.ua/handle/123456789/27209.

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Анотація:
Постійний інтерес, що проявляють дослідники, які працюють у галузі фізики конденсованого стану та фізичного металознавства змішаних систем, до досліджень матеріалів з особливими механічними, тепловими, електричними, магнітними та ін. властивостями, обумовлений прагненням пояснити різноманітність притаманних унікальних властивостей, користуючись загальними принципами, та розробити принципи оптимізації режимів синтезу та термочасової обробки для формування певної структури цих матеріалів. У той самий час у науковій літературі дані про структурний і напружений стан таких плівок та узагальнення про експериментальні дослідження кінетичних, теплових, гальваномагнітних, локальних та інтегральних магнітних властивостей аморфних металевих сплавів (АМС) нечисленні, несистематизовані та суперечливі. При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/27209
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20

Pietzsch, Oswald. "Magnetic imaging by spin-polarized scanning tunneling spectroscopy applied to ultrathin Fe/W(110) films." [S.l.] : [s.n.], 2001. http://www.sub.uni-hamburg.de/disse/444/Disse.pdf.

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21

Tsurkan, Sergey [Verfasser]. "Magnons in ultrathin Fe/Co multi-layers on W(110) and Ir(111) / Sergey Tsurkan." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1227451245/34.

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22

Eliasson, Anders. "Liquid phase sintering of W-Ni-Fe composites : liquid penetration, agglomerate separation and tungsten particle growth." Doctoral thesis, KTH, Keramteknologi, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3870.

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Анотація:
The initial stage of liquid phase sintering, involving liquid penetration, agglomerate separation, particle spreading and growth has been investigated in experiments using tungsten heavy alloys. The particle composites used were produced by hot isostatic pressing (HIP) of pure powder mixtures of W-Ni-Fe-(Co). By using different HIP temperatures, volume fractions of tungsten, alloying elements like Cobalt and Sulphur or excluding Iron from the matrix, liquid penetration, agglomerate separation and particle growth conditions were affected. The investigations were performed mainly under microgravity (sounding rockets or parabolic trajectories by airplanes) but at high tungsten particle fractions, short sintering times or at infiltration of solid pure tungsten, they were performed at normal gravity. The liquid penetration of the tungsten agglomerates is explained by initial wetting under non-equilibrium conditions, due to the reaction between the liquid matrix and the particles, and a decrease of interfacial energy. The dissolving of tungsten gives a pressure drop in the penetrating liquid and a driving force for the liquid movement by a suggested parabolic penetration model. For cold worked tungsten, a penetration theory was proposed, where an internal stress release in the penetrated tungsten grains creates space for the advancing liquid. The spreading of the tungsten agglomerates is explained by an interagglomerate melt swelling due to a Kirkendall effect. The liquid matrix undergoes a volume increase since the diffusion rates of Ni-Fe are higher than for W and initial concentration gradients of W and Ni, Fe exists. The suggested model by Kirkendall are also used for an analysis of the interaction behaviour between solid particles and a solidification front and inclusion behaviour in iron base alloys during teeming and deoxidation. The average tungsten particles size decrease initially since part of the tungsten particles is dissolved when the non-equilibrium matrix phase is melting. When equilibrium is reached, the tungsten particles grow in accordance with the Ostwald ripening process by an approximately 1/3 power law. Larger particle fraction of particles showed a higher growth rate, due to shorter diffusion distances between the particles. Cobalt, Sulphur and absence of iron in the matrix were found to increase the growth rate of the tungsten particles due to a higher surface tension between the solid tungsten particles and the matrix melt.
QC 20100528
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23

Johnston, Hamish L. "A study of the magnetic and structural properties of ultrathin Fe/Ni(111)/W(110) films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ30149.pdf.

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24

Johnston, Hamish. "A study of the magnetic and structural properties of ultrathin Fe/Ni(111/W(110) films /." *McMaster only, 1997.

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25

Eliasson, Anders. "Liquid phase sintering of W-Ni-Fe composites : initial melt penetration, agglomerate separation and particle interaction /." Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3870.

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26

Pacaud, Jérôme. "Effets d'irradiations aux ions observés dans des multicouches : cas des systèmes Cu-W et Fe-Si." Poitiers, 1993. http://www.theses.fr/1993POIT2265.

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Анотація:
Nous etudions les effets induits par irradiation a basse temperature dans le systeme metallique non miscible cu-w. Nous avons observe une relaxation des contraintes a des faibles doses d'irradiation. Nous avons etudie le melange ionique produit par les differents ions dans chaque element. Nous mettons en evidence les effets de temps de refroidissement de cascade et de coefficient de diffusion a l'etat liquide
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27

Patterson, Veronica A. "Activity and selectivity of transition metal (Fe, Mo and W) carbides in the Fischer-Tropsch synthesis." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/14729.

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Анотація:
Includes bibliographical references (leaves 99-107).
This study focused on the Fischer-Tropsch activity and selectivity of transition metal (iron, molybdenum and tungsten) carbides. The carbide catalysts were prepared by a temperature programmed method. The properties of the materials were characterised by X-ray diffraction (XRD), transmission electron microscopy (TEM), BET measurements and temperature programmed desorption of carbon monoxide (CO-TPD). The performance of the materials was tested in a Berty reactor. A reduced, precipitated iron oxide catalyst was used as a reference catalyst.
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Bucher, Sébastien. "Synthèse, caractérisation et aptitude à la mise en forme de poudres revêtues, applications aux systèmes Fe-N, WC-Co, W-Cu et W-Ag." Poitiers, 2007. http://www.theses.fr/2007POIT2344.

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L’intérêt des poudres revêtues porte sur de multiples aspects fondamentaux et appliqués : - Homogénéité dans la répartition des constituant bien supérieure à celle que l’on obtient par une simple opération de mélange. Les mécanismes diffusionnels et réactionnels responsables de la densification lors du frittage sont accélérés. - Combinaison des propriétés caractéristiques du matériau de base et du matériau de revêtement, ouvrant la voie à de très nombreuses possibilités et à la conception de poudres à gradient de fonction. Les différentes techniques utilisées dans ce travail pour la synthèse de poudres revêtues ont recours au lit fluidisé comme média de traitement pour obtenir un brassage optimal des grains lors des réactions de dépôt. Selon les revêtements envisagés, les traitements sont conduits en phase gazeuse (thermochimie, CVD) ou en phase liquide (dépôt chimique autocatalytique). Les systèmes étudiés sont à forts potentiels industriels (WC-Co, W-Cu, W-Ag) ou possèdent un intérêt plus fondamental (Système (Fe-N). Après leurs synthèses et leurs caractérisations, l’aptitude à la mise en forme de ces poudres est évaluée par compactage/frittage conventionnel. Parallèlement, des mélanges équivalents sont réalisés afin d’établir un comparatif entre poudres mélangées et revêtues, au niveau de la compressibilité et du comportement au frittage. Pour tous les systèmes, une densité maximale après frittage est recherchée, et les différentes caractérisations réalisées tendent à démontrer le bénéfice apporté par l’utilisation de poudres revêtues. De plus, un gain significatif est apporté pour la tenue à vert des comprimés lors de l’utilisation de poudres revêtues
In the field of powder metallurgy, there is a growing interest in coated powders that are of interest for fundamental and applied aspects: - A better homogeneity is fulfilled for the repartition of the different components. Diffusional and reactional mechanisms responsible of their densification during the sintering are improved. - The combination of properties of the core material and those of the shell opens a new route for the synthesis of powders with gradients functions. In this work, the processes used for the synthesis of coated particles are based on fluidized bed as a treatment medium that allows obtaining an optimal mixing of the powders during the deposition of coatings. Depending on the nature of the coating, the treatments used were performed in a gaseous atmosphere (Chemical Vapor Deposition and thermochemical treatment) or in a liquid phase (Autocatalytic processes). The choice of the different systems (core particle/ coating) was based on industrial considerations (WC-Co, W-Cu and W-Ag) and on fundamentals aspects (Fe-N). After the description of the different ways of synthesis of coated powders, their consolidation capabilities are evaluated by classical compacting/sintering processes. At the same time coated powders and equivalent mixing powders were realized to better understand the advantages of using coated particles for the compressibility and sintering ability. For every system, the highest density after sintering is required. For this point, the different microstructural characterizations performed in this work reveal the benefits of using coated powders. Furthermore, green strength of compressed samples is greatly improved with coated powders
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29

Arnold, C. S. "Magnetic susceptibility observation of a spin-reorientation transition in Fe/2 ML Ni(111)/W(110) films." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30067.pdf.

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30

Yermolenko, I. Yu, M. V. Ved, N. D. Sakhnenko, and A. V. Karakurkchi. "The effect of the electrolysis regime on the composition and morphology of Fe–Co–Mo(W) coatings." Thesis, Publishing House SME "Burlaka", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41551.

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31

Krause, Stefan. "Thermal and current-induced magnetization switching of Fe, W (110) nanoislands investigated by spin-polarized scanning tunneling microscopy." Göttingen Cuvillier, 2008. http://d-nb.info/995845824/04.

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32

Piaszenski, Guido. "Aufbau eines UHV-Tieftemperatur-Rastertunnelmikroskops zur Untersuchung atomarer Diffusionseffekte am Beispiel von Fe(110), W(110) und Cu(111)." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965444570.

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33

Reshöft, Klaus. "Zeitaufgelöste STM-Untersuchungen zur Silizid- und Metall-Epitaxie der Systeme Fe-, Cu-, Pt-Si(111) und Cu-W(110)." [S.l. : s.n.], 2001. http://e-diss.uni-kiel.de/diss>=/d525.pdf.

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34

Chuang, Tzu-Hung [Verfasser], J. [Akademischer Betreuer] Kirschner, G. [Akademischer Betreuer] Schmidt, and H. [Akademischer Betreuer] Wende. "High wave-vector magnon excitations in ultrathin Fe(111) films grown on Au/W(110) and Fe(001) films grown on Ir(001) / Tzu-Hung Chuang. Betreuer: J. Kirschner ; G. Schmidt ; H. Wende." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2013. http://d-nb.info/1033306665/34.

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35

Mengason, Michael J. "Experimental study of the partitioning of Cu, Ag, Au, Mo and W among pyrrhotite and immiscible Fe-S-O and silicate melts." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7401.

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Thesis (M.S.) -- University of Maryland, College Park, 2007.
Thesis research directed by: Dept. of Geology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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36

Rodrigues, Eloise Cristina de Souza. "S?ntese e caracteriza??o de nanocomp?sitos de part?culas de ?-Fe, w?stita e magnetita para aplica??es biom?dicas." PROGRAMA DE P?S-GRADUA??O EM F?SICA, 2017. https://repositorio.ufrn.br/jspui/handle/123456789/23512.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Nanopart?culas de ?xido de Fe t?m sido muito usadas em aplica??es biom?dicas devido a sua biocompatibilidade e biodegradabilidade. Dentre dessas aplica??es destacamos a hipertermia magn?tica para o tratamento de diversos tipos de c?nceres. Neste trabalho usamos a moagem de alta energia para a produ??o de nanopart?culas de magnetita com tamanho inferior a 70 nm. Preparamos dois grupos de amostras, o primeiro grupo apresentou as fases de magnetita e ?-Fe, composto pelas amostras S1 e S3, o segundo grupo apresentou as fases de magnetita, ?-Fe e w?stita, amostras S2 e S4. Para melhorar a dispers?o dos materiais em meio aquoso, revestimos as nanopart?culas com o surfactante ?cido oleico e o pol?mero Pluronic-F127. As propriedades estruturais e qu?micas das amostras foram analisadas atrav?s da difra??o de raios X, microscopia eletr?nica de transmiss?o e espectroscopia M?ssbauer. As propriedades magn?ticas foram estudadas atrav?s de medidas de susceptibilidade AC e de medidas de magnetiza??o em fun??o do campo e da temperatura. Das medidas M?ssbauer, para a amostra S4, observamos uma raz?o entre as ?reas dos espectros referentes aos s?tios octaedrais e tetraedrais compat?veis com a magnetita estequiom?trica. As medidas magn?ticas mostraram a transi??o de Verwey da magnetita em 120 K para os dois grupos de amostras. Atrav?s das imagens de microscopia eletr?nica, de S4, verificamos que a w?stita encontra-se depositada sobre as nanopart?culas de magnetita. O nosso estudo mostra que a presen?a da w?stita e a funcionaliza??o com ?cido oleico evitaram a oxida??o do Fe2+ presente na magnetita. O deslocamento das curvas de histerese, nas medidas feitas com a amostra resfriada em presen?a de campo magn?tico, ? atribu?do ? intera??o de troca que ocorre na interface entre a w?stita e a magnetita. As medidas de susceptibilidade AC mostraram picos caracter?sticos de paredes de dom?nio, para a amostra com duas fases, indicando que uma parcela das part?culas ? multidom?nio. Quando as nanopart?culas funcionalizadas e n?o funcionalizadas foram submetidas a um campo magn?tico alternado apresentaram uma varia??o de temperatura e 11? C e 53? C, para S3P e S1, respectivamente, e para S4 a varia??o de temperatura foi de 14? C. Os resultados indicam que as amostras t?m potencial para uso em hipertermia magn?tica.
Oxide nanoparticles have been used in several biomedical applications due to their biocompatibility and biodegradability. Among these applications, magnetic hyperthermia of tumors has been proposed as an alternative treatment of several neoplastic diseases. In this work, we have used high energy milling to produce iron oxide nanoparticles with sizes smaller than 70 nm. We have prepared two groups of samples, the first group is composed of magnetite and ?-Fe, samples S1 and S3, the second group is composed of magnetite, w?stite and ?-Fe nanoparticles, samples S2 and S4. To improve the sample?s dispersibility in aqueous medium, the samples were functionalized with oleic acid and Pluronic-F127 three-block copolymer. The structural and chemical properties of samples were studied through x-ray diffraction, transmission electron microscopy (TEM) and M?ssbauer spectroscopy. The magnetic properties were studied through AC susceptibility and DC magnetization as a function of temperature and field. From the M?ssbauer studies, for the sample S4, we observed a ratio between the areas of the spectra for the octahedral and tetrahedral compatible with stoichiometry magnetite. The magnetic measurements showed the Verwey transition at about 120 K, for the two groups of samples. From the TEM images, S4, we verified that the w?stite phase is formed on the magnetite nanoparticles. Therefore, we showed that the w?stite phase and oleic acid surfactant prevent the magnetite nanoparticles from further oxidation. The shift of hystereis loops observed in the field cooled samples is ascribed to exchange interaction between the w?stite and magnetite phases. The AC susceptibility, from S4, showed characteristic peaks of magnetite wall domains, this result indicated that a fraction of particles are multidomain. The samples were submitted to an AC magnetic field and we observed an increase in temperature of e 11? C and 53? C for samples functionalized and bare, for S1 and S4 respectively, for sample S4, the increase in temperature, was of 14? C. The combination of magnetic properties, the ability to release heat in presence of an AC, and the stability of particles in aqueous suspension suggest that these samples are good candidates for magnetic hyperthermia.
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37

Baus, Picard Jorge. "L'Accumulation des cations (K. Ca. Mg. Na et Fe) et l'adaptation de Dittrichia (ex inula) viscosa W. Greuter aux sols acides et calcaires." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595770c.

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38

Peixoto, Thiago Ribeiro Fonseca. "Análise FORC em nanofios de Ni e Co e excitação de mágnons de superfície em filmes de O-Fe/W(001) via SPEELS." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-26012011-124128/.

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Estudamos o comportamento estático e os mecanismos de inversão da magnetização de arranjos auto-organizados de nanofios de Ni e Co com alta anisotropia de forma. Os arranjos são obtidos a partir da anodização em dois passos de lâminas de Al e subseqüente eletrodeposição do metal magnético. Sua caracterização estrutural é realizada por microscopia eletrônica de varredura, microscopia de força atômica e magnética e difração de raios X. Seu comportamento magnético é estudado a partir da medida de curvas de inversão de primeira ordem (FORCs) a temperatura ambiente, via magnetometria SQUID ou de amostra vibrante. A análise FORC consiste na construção de uma mapa da resposta magnética do material a partir dos dados experimentais e pode ser interpretado a partir da analogia direta com o modelo de histerese de Preisach. Apresentamos resultados da influência dos diâmetros dos nanofios e do ângulo do campo externo aplicado em relação ao eixo de anisotropia sobre as principais características dos diagramas FORC. Estudamos também a dinâmica de spins em superfícies de O-Fe/W(001) através de espectroscopia por perda de energia de elétrons spin-polarizados (SPEELS). As amostras consistem em 30 monocamadas atômicas de Fe crescidas sobre um monocristal de W(001), via epitaxia por feixe molecular a temperatura ambiente. Subseqüentemente, a amostra é exposta a 5 langmuirs de O2 e sofre um suave annealing a 500 K. A estrutura e a pureza da amostra são analisadas por difração de elétrons de baixas energias e espectroscopia de elétrons Auger. A caracterização magnética é realizada por magnetometria por efeito Kerr magneto-óptico, resultando num filme com alta magnetização remanente no plano. Os espectros de SPEELS revelam uma rica profusão de picos inelásticos tipo spin-flip e nãospin-flip, que exibem clara dispersão ao longo de toda a zona de Brillouin de superfície. Os resultados são atribuídos a modos de superfície de fônons e mágnons (ondas de spin), de acordo com resultados da literatura e com modelos teóricos atuais.
We study the static behavior and the mechanisms of magnetization reversal of arrays of self-organized Ni and Co nanowires with high shape anisotropy. The arrays are obtained by two-step anodization of Al foils and subsequent electrodeposition of the magnetic metal.Their structural characterization is obtained by scanning electron microscopy, atomic and magnetic force microscopy and X-ray diffraction. Their magnetic behavior is studied from the measurement of first order reversal curves (FORCs) at room temperature, via SQUID or vibrating sample magnetometry. The FORC analysis method consists in building a map of the magnetic response of the material from the experimental data and it can be interpreted from the direct analogy with the Preisach model of hysteresis. We present results of the influence of the diameter of the nanowires and the angle of the applied external field in relation to the anisotropy easy-axis on the main features of the FORC diagrams. We also study the spin dynamics of O-Fe/W(001) surfaces through spin-polarized electron energy loss spectroscopy (SPEELS). The samples consist of 30 atomic monolayers of Fe grown on a W(001) single crystal via molecular beam epitaxy at room temperature. Subsequently, the samples are exposed to 5 langmuirs of O2 and suffer a mild annealing at 500 K. The structure and purity of the samples are analyzed by low-energy electron diffraction and Auger electron spectroscopy. The magnetic characterization is performed by magneto-optical Kerr effect magnetometry, resulting in films with high remanent in-plane magnetization. SPEEL-spectra reveal a rich profusion of inelastic spin-flip and non-spin-flip peaks, which exhibit clear dispersion for wave vectors throughout the whole surface Brillouin zone. The results are attributed to surface modes of phonons and magnons (spin waves), in accordance with the literature and with current theoretical models.
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39

Marchionni, Christian. "Etude phénoménologique du frittage des alliages lourds W-Ni-Fe à partir de facteurs géométriques (poudres) et chimiques (additions de Co et de Mn)." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37607707d.

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40

Marchionni, Christian. "Etude phénoménologique du frittage des alliages lourds W-Ni-Fe à partir de facteurs géométriques (poudres) et chimiques (additions de Co et de Mn)." Grenoble INPG, 1987. http://www.theses.fr/1987INPG0118.

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41

FRADIN, VALERIE. "Etude comparative, par annihilation de positrons, de la relaxation structurale d'alliages amorphes electrodeposes w-metal de transition (fe, co, ni) et hypertrempes a base cobalt." Paris, ENSAM, 1997. http://www.theses.fr/1997ENAM0001.

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Des alliages amorphes binaires w-metal de transition (fe, co, ni) d'une teneur d'environ 20% at. W ont ete elabores par electrodeposition en milieu basique a 80c a partir de bains a base tartrate. L'evolution microstructurale de ces depots de 150 m d'epaisseur soumis a des recuits en dents de scie d'amplitude croissante, a ete etudiee par spectroscopie d'annihilation des positrons qui est sensible a la presence de defauts de type lacunaire et par analyse thermique. Les mesures de temps de vie et d'elargissement doppler ont montre que dans ces alliages amorphes electrodeposes, au moins deux types de defauts structuraux dominent le processus de piegeage du positron qui sont associes a des defauts de type lacunaire et a des bulles d'hydrogene. Leur reorganisation structurale qui donne lieu a une dimunition significative du volume libre present initialement dans le depot, procede en deux etapes : une premiere etape de depiegeage de l'hydrogene occlus au cours de l'electrodeposition des defauts de type lacunaire et de formation d'agregats de type lacunaire suivie d'une seconde etape d'elimination du nombre total de sites de piegeage a laquelle se superpose une tres probable precipitation du tungstene environ 200c avant que la recristallisation ne soit visible par diffraction des rayons x. D'autre part, les etudes par annihilation des positrons ont suggere que les depots amorphes ne se trouvent pas a l'etat brut de preparation au meme etat d'avancement de leur evolution structurale : les energies de depiegeage de l'hydrogene qui vont croissantes selon l'ordre fer, nickel, cobalt laissent supposer que la liberation de l'hydrogene est plus precoce pour le depot a base fer que pour celui a base nickel et cobalt. L'evolution microstructurale apparait donc comme un processus inhomogene impliquant la formation d'amas lacunaires alors que dans le cas d'un amorphe hypertrempe de type metal-metalloide, elle semble controlee principalement par l'ordre chimique a courte distance.
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42

Corbetta, Marco [Verfasser], J. [Akademischer Betreuer] Kirschner, W. [Akademischer Betreuer] Widdra, and C. M. [Akademischer Betreuer] Schneider. "Spin-polarized scanning tunneling microscopy and spectroscopy study of Fe and Co nanostructures on Cu(111) / Marco Corbetta. Betreuer: J. Kirschner ; W. Widdra ; C. M. Schneider." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2013. http://d-nb.info/1038211212/34.

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43

Hugel-Le, Goff Catherine. "Synthèse et étude des systèmes 1-phosphaallyliques : un accès général aux ligands eta3-1-phosphaallyles de MO, W, FE, CO et NI et particulier aux phosphaalcènes." Palaiseau, Ecole polytechnique, 1990. http://www.theses.fr/1990EPXX0003.

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Анотація:
Les systèmes 1-phosphaallyliques, objet de cette thèse, se situent à la croisée de deux grandes familles de composes: les complexes pi-allyliques et les dérivés phosphores ligands de métaux de transition. En premier lieu sera abordé l'aspect synthèse et réactivité des eta3-allyles carbones, suivi d'une présentation des valences et des modes de coordination varies des ligands phosphores. Le but de la thèse sera introduit par les résultats déjà publiés de quelques laboratoires travaillant sur les hétéroallyles. Le chapitre essentiel intitule synthèses effectuées et discussions vise à rassembler les synthèses aboutissant aux complexes eta3-1-phosphaallyles de métaux de transition qui seront scindes en deux: les eta,eta3-1-phosphaallyles du chrome, du molybdène, du tungstène et du fer, et les eta3-1-phosphaallyles du cobalt et du nickel. Ainsi seront mis en lumière les propriétés intrinsèques et la capacite de ces complexes a pouvoir varier leur mode de coordination. Parmi les différents équilibres passés en revue, on remarquera celui de l'isomérisme générant un phosphaalcène à partir d'une simple phosphine vinylique. La conclusion de ce mémoire tentera de résumer l'apport de ces synthèses a la compréhension des 1-phosphaallyles et se posera le problème de leur mise en application en catalyse
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44

Михалицына, Е. А. "Магнитная анизотропия и гистерезисные свойства аморфных и нанокристаллических пленок Fe-M-Cu-Si-B (M: Nb, NbMo, W) : диссертация на соискание ученой степени кандидата физико-математических наук : 01.04.11". Thesis, б. и, 2018. http://hdl.handle.net/10995/58816.

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45

Михалицына, Е. А. "Магнитная анизотропия и гистерезисные свойства аморфных и нанокристаллических пленок Fe-M-Cu-Si-B (M: Nb, NbMo, W) : автореферат диссертации на соискание ученой степени кандидата физико-математических наук : 01.04.11". Thesis, б. и, 2018. http://hdl.handle.net/10995/58815.

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46

Pereira, Luis Gustavo da Silva. "Avaliação do mecanismo de oxidação de hidrogênio contaminado por monóxido de carbono em células PEMFC contendo catalisadores anódicos baseados em Pt-M/C (M=Ru, Mo, Fe e W)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75131/tde-11032010-110241/.

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A busca por fontes alternativas de energia é uma tendência mundial e, neste contexto, as células a combustível alimentadas com hidrogênio obtido pela reforma de biocombustíveis constitui uma das alternativas mais promissoras. Entretanto, o desempenho das células a combustível de membrana de troca protônica (PEMFC) com ânodos baseados em Pt é drasticamente reduzido quando se utiliza hidrogênio contaminado por CO, o qual é produzido no processo de reforma. Neste trabalho, a eletrocatálise da tolerância ao CO e a estabilidade de Pt/C, PtRu/C, PtFe/C, PtMo/C e PtW/C como eletrocatlisadores anódicos de célula a combustível PEM foram investigadas através de curvas de polarização e medidas on line de espectrometria de massas (EMS), análises de voltametria cíclica, difração de raios X (DRX) e absorção de raios X (XAS). Para todos os eletrocatalisadores bimetálicos, os quais apresentaram alta tolerância ao CO, os resultado de EMS mostraram que a produção de CO2 inicia-se a menores sobrepotenciais em relação ao eletrodo de hidrogênio quando comparado a Pt/C, confirmando a ocorrência do conhecido mecanismo bifuncional. Por outro lado, os resultados de XANES indicam um aumento de vacância da banda 5d da Pt para todos os catalisadores bimetálicos, particularmente para PtFe/C, o que leva a um enfraquecimento da ligação Pt-CO e conseqüente aumento da tolerância ao CO (efeito eletrônico). Para PtMo/C e PtRu/C alimentado com H2/CO, a formação de CO2 é observada mesmo quando a célula opera em circuito aberto, confirmando alguma eliminação de CO por um processo químico, muito provavelmente uma reação de deslocamento gás-água. Uma deterioração do desempenho de célula a combustível foi observada em uma função do tempo de operação. As causas desta degradação durante a operação a longo prazo fazem parte de um processo complexo que envolve diversos mecanismos paralelos, tais como: perda ou redistribuição do eletrocatalisador, corrosão do suporte de carbono e degradação do eletrólito (Nafion®).
The search for alternative sources of energy is a global trend, and in this context, the fuel cell supplied with hydrogen obtained by biofuels reforming is one of the most promising alternative. However, the performance of proton exchange membrane fuel cells (PEMFC) with Pt-based anode is drastically lowered when using CO-contain hydrogen, as that produced by reform. In this work, the electrocatalysis of CO tolerance and the stability of Pt/C, PtRu/C, PtFe/C, PtMo/C, and PtW/C electrocatalysts at a PEM fuel cell anode has been investigated using single cell polarization and on line electrochemical mass spectrometry (EMS) measurements, and cyclic voltammetry, X-ray diffraction (XRD), and X-ray absorption near edge structure (XANES) analyses of the electrocatalysts. For all bimetallic electrocatalysts, which presented higher CO tolerance, EMS results have shown that the production of CO2 starts at lower hydrogen electrode overpotentials as compared to Pt/C, confirming the occurrence of the so-called bifunctional mechanism. On the other hand, XANES results indicate an increase in the Pt 5d-band vacancies for the bimetallic catalysts, particularly for PtFe/C, this leading to a weakening of the Pt-CO bond, helping to increase the CO tolerance (the so-called electronic effect). For PtMo/C and PtRu/C supplied with H2/CO, the formation of CO2 is observed even when the cell is at open circuit, confirming some elimination of CO by a chemical process, most probably the water gas shift reaction. A decay of the fuel cell performance was observed as a function of the operation time. The causes of degradation during long-term operation were found to be a complex process that involves several parallel mechanisms, including: electrocatalyst loss or redistribution, carbon corrosion, and electrolyte (Nafion®) degradation.
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Schröders, Sebastian J. [Verfasser], Sandra [Akademischer Betreuer] Korte-Kerzel, and W. J. [Akademischer Betreuer] Clegg. "Plasticity of topologically close packed phases : characterisation from high temperature to high resolution in a case study of the Fe$_7}$Mo$_6}$-µ-phase / Sebastian J. Schröders ; Sandra Korte-Kerzel, W. J. Clegg." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1181108780/34.

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48

Fruchart, Olivier. "Elaboration, étude et modélisation d'un système magnétique modèle : réseaux de plots sub-microniques ultraminces de Fe(110) épitaxié à anisotropie planaire." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10094.

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L'objectif de cette these etait l'elaboration, l'etude et la modelisation des processus de renversement de l'aimantation dans un systeme modele : des plots submicroniques ultraminces epitaxies a aimantation planaire. Nous avons montre en depot laser pulse (dlp) par analyse rheed et afm que le procede habituel de depot a t<800c des couches tampons de w et mo sur al#2o#3 induisait une rugosite importante. Nous proposons un nouveau procede fonde sur un depot a 200c, un recuit a 800c et une poursuite de depot a 800c, qui permet l'obtention de couches monocristallines de mo(110) dont la surface est composee de larges terrasses atomiques, permettant par consequent la croissance de couches de fer(110) de haute qualite. L'utilisation des techniques de lithographie x et de gravure seche ont ensuite permis de realiser des reseaux de dizaines de millions de plots (particules) identiques, de dimensions laterales de 200nm a 500nm. Pour les reseaux etudies les interaction dipolaires entre particules peuvent etre negligees. L'analyse magnetique des couches continues a montre que le systeme mo/fe(110) (peu etudie jusqu'alors) presente une anisotropie d'interface planaire qui favorise l'axe 001 au detriment de $$110, DE MEME INTENSITE MAIS DE SIGNE OPPOSE A CELLE DE W/FE(110), ET QUI PERMET D'ATTEINDRE DES CHAMPS D'ANISOTROPIE SUPERIEURS A 0. 5T AUX FAIBLES EPAISSEURS DE FE. AU DESSUS DE 10MC (MONOCOUCHES) LE RETOURNEMENT S'EFFECTUE A CHAMP FAIBLE PAR NUCLEATION SUR UN DEFAUT ISOLE PUIS PAR PROPAGATION LIBRE ET IMMEDIATE D'UNE PAROI. AU DESSOUS DE 5MC LES PAROIS SONT PIEGEES DU FAIT DES FLUCTUATIONS SPATIALES DISCRETES DE L'EPAISSEUR DE LA COUCHE DE FER. LA GRAVURE EN PARTICULES EMPECHE LE BALAYAGE DES PAROIS ET INDUIT UNE TRES FORTE AUGMENTATION DE COERCITIVITE, QUI EST D'AUTANT PLUS IMPORTANTE QUE L'EPAISSEUR EST FAIBLE (DU FAIT DE LA DIMINUTION DES CHAMPS DEMAGNETISANTS INTERNES AUX PARTICULES), JUSQU'A ATTEINDRE H#C = 0. 73H#A POUR E = 1NM. LE COMPORTEMENT HC() MESURE EST TRES PROCHE DE LA LOI DE STONER-WOHLFARTH, BIEN QUE LE RETOURNEMENT NE SOIT PAS COHERENT PUISQUE LE VOLUME DE NUCLEATION (DETERMINE PAR HC(T) ET TRAINAGE) NE REPRESENTE QUE 1% DU VOLUME D'UNE PARTICULE. DES MESURES DE PARTICULES INDIVIDUELLES PAR MICROSQUID CONFIRMENT QUE LES PARTICULES SONT ESSENTIELLEMENT UNIFORMEMENT AIMANTEES, ET MONTRENT EGALEMENT QUE LA DISTRIBUTION DES CHAMPS DE RETOURNEMENT D'UNE PARTICULE UNIQUE EST FAIBLE. NOUS PROPOSONS UNE METHODE POUR EVALUER LE CYCLE D'HYSTERESIS MOYEN D'UNE PARTICULE UNIQUE A PARTIR DE LA MESURE MACROSCOPIQUE DU CYCLE D'HYSTERESIS ET DE LA SUSCEPTIBILITE REVERSIBLE DU RESEAU. NOUS AVONS EGALEMENT DEVELOPPE UN MODELE MICROMAGNETIQUE DE RETOURNEMENT DE L'AIMANTATION SPECIFIQUE AUX PARTICULES ULTRAMINCES A AIMANTATION PLANAIRE, ET QUI PREDIT, EN FONCTION DE L'EPAISSEUR DU PLOT, LA REDUCTION DE CHAMP COERCITIF HC PAR RAPPORT AU CHAMP D'ANISOTROPIE, C'EST A DIRE PAR RAPPORT AU CHAMP DE RETOURNEMENT COHERENT. DES SIMULATIONS NUMERIQUES ONT MONTRE D'UNE PART LA PERTINENCE DU MODELE, D'AUTRE PART QU'AU DELA D'UNE TAILLE LATERALE DE L'ORDRE DE 50 A 100NM LA TAILLE LATERALE DU PLOT N'INFLUENCE PLUS LA VALEUR DE LA COERCITIVITE, QUI EST ALORS DETERMINEE UNIQUEMENT PAR L'EPAISSEUR DU PLOT. L'ACCORD EST RELATIVEMENT BON ENTRE MODELE ET SIMULATION D'UNE PART, EXPERIENCE D'AUTRE PART, MEME SI LA COERCITIVITE CALCULEE EST TOUJOURS PLUS ELEVEE QUE CELLE OBSERVEE.
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49

AGUSTIN, DOMINIQUE. "Bases de schiff et coordinences non usuelles du germanium, de l'etain et du plomb : (base de schiff)m(ii), (base de schiff)m = x et (base de schiff)m n = ml m (m = ge, sn, pb ; x = s, se, n-sime 3 ; m = w, cr, fe et mn ; n = 1, 2)." Toulouse 3, 1999. http://www.theses.fr/1999TOU30162.

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Ce travail concerne l'etude d'especes organometalliques stables des types >m, >m = y (y = o, s, se, n-sime 3) et (>m) nm (m : metal de transition) a metal 14 a coordinence non usuelle. Le premier chapitre est une mise au point bibliographique concernant les basses coordinences stables des types > m et (> m) nm (m = ge, sn, pb). Le deuxieme chapitre concerne la synthese et l'etude physicochimique des nouvelles especes divalentes l 2m (m = ge, sn, pb ; l 2 = base de schiff). Les donnees spectroscopiques soulignent la coordination intramoleculaire n-m-n. Des reactions de cycloaddition et la structure rx de l'adduit (salen)sn-3,5-di-tert-butyl-1,2-benzoquinone sont presentes. Des insertions d'aldehydes ou de clivage par des acides organiques et des chlorures d'acides conduisent, a partir de (salen)m, a de nouveaux composes divalents heteroleptiques. Le troisieme chapitre concerne les complexes (salen)m nm(co) 6 - n (m = ge, sn, pb ; m = cr, w, n = 1, 2) 2. Les structures rx indiquent le caractere double de la liaison sn = m. Les complexes (salen)m = m(co) 5 (m = ge, sn ; m = cr, w) conduisent, par des reactions de cycloaddition et de substitution de ligands, a de nouvelles especes a enchainement p-w-sn ou a des composes trimetalles sn-m-sn (m = cr, w). Le quatrieme chapitre decrit les complexes (salen)m = mncp(co) 2 (m = ge, sn, pb), (salen)sn = fe(co) 4 et leurs structures rx. Le caractere double de la liaison (salen)m-ml n, du au caractere -donneur et au fort caractere -accepteur de (salen)m, est demontre par l'obtention de la plus courte liaison sn-mn connue dans (salen)sn = mn(cp)(co) 2. La position axiale de (salen)sn dans la structure de (salen)sn = fe(co) 4 demontre que (salen)sn est plus -donneur que -accepteur vis-a-vis du fer. Le cinquieme chapitre traite de la reactivite des especes divalentes (salen)m vis-a-vis d'oxydants conduisant a de nouvelles especes insaturees de type (salen)m = y (m = ge, sn ; y = s, se, n-sime 3) ; certains aspects de leur reactivite sont egalement presentes. La derniere partie concerne des transferts de ligands entre (salen)sn et des composes halogenes (bf 3. Me 2o, cp 2ticl 2, nicl 2. Dppe, pcl 3, tbupcl 2, cl 3p = x (x = o, s)) conduisant a de nouveaux composes lineaires ou cycliques a ligand salen du bore, du titane, du nickel et du phosphore (neutres ou cationiques).
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50

Cahlík, Aleš. "Spektrální analýza a charakterizace magnetických atomů a studium supravodivých vrstev pomocí nízkoteplotní STM." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254337.

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This work is divided in two thematic parts. The first part shows a refurbishment of a Omicron low temperature STM set-up and its utilization for preparation of superconducting-magnetic interfaces. First, a cleaning procedure of suitable metallic substrates, specifically W(110) and Ir(111), is shown. It is followed by results of iron monolayer deposition on Ir(111) (Fe-Ir(111) interface). The last section deals with study of vanadium growth on pure Ir(111) substrate as well as on mentioned Fe-Ir(111) interface. The second thematic part deals with magnetism of cobalt atoms on a monolayer metal dichalcogenide WS2. It focuses primarily on studying their magnetic moment and magnetic anisotropy using X-ray magnetic circular dichroism (XMCD).
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