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Master's Dissertation
DOI
10.11606/D.97.2010.tde-26092012-140655
Document
Author
Full name
André Brauner
Institute/School/College
Knowledge Area
Date of Defense
Published
Lorena, 2010
Supervisor
Committee
Machado, Antonio Jefferson da Silva (President)
Jardim, Renato de Figueiredo
Oliveira Junior, Nei Fernandes de
Title in Portuguese
Estudo das propriedades supercondutoras da fase T2 no sistema Nb-Si-B
Keywords in Portuguese
Estrutura lamelar
Fase T2 no sistema Nb-Si-B
Intersticial
Supercondutividade
Abstract in Portuguese
Este trabalho tem como objetivo o estudo da influência do boro na fase αNb5Si3 (Fase T2) a baixas temperaturas analisando suas propriedades elétricas e magnéticas. Para o estudo deste tema as amostras foram preparadas, seguindo a estequiometria Nb5Si3-xBx, via metalurgia do pó e também por fusão a arco, com x dentro do intervalo limitado por 0  X  1,0. Estas amostras foram analisadas através de difratometria de raios x, microscopia eletrônica de varredura, magnetização, transporte elétrico e medidas calorimétricas em baixa temperatura. As medidas das propriedades elétricas e magnéticas destas fases mostram que a substituição de boro por silício induz supercondutividade na fase T2. O caráter volumétrico da transição supercondutora é confirmado pela medida de capacidade calorífica. Assim, este trabalho é o primeiro a mostrar uma nova família de materiais supercondutores que cristalizam na estrutura protótipo Cr5B3.
Title in English
Study of superconducting properties of the T2 phase in the system Nb-Si-B.
Keywords in English
interstitial and T2 phase in the system Nb-Si-B
Lamellar structure
new superconducting material
Superconductivity
Abstract in English
This work to study the influence of boron during low temperature αNb5Si3 (T2 phase) analyzing their electrical and magnetic properties. For the study of this subject the samples were prepared, following the stoichiometry Nb5Si3-xBx via powder metallurgy and also by arc melting process, with x within the range limited by 0X1.0. These samples were analyzed by X-ray diffraction, scanning electron microscopy, magnetization, electrical transport and calorimetric measurements of low temperature. Measurements of electrical and magnetic properties of these phases show that the substitution of boron by silicon induces superconductivity at the T2 phase. The bulk nature of superconducting transition is confirmed by heat capacity measurement. This study is the first to show a new family of superconducting materials that crystallize in the Cr5B3 prototype structure.
 
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EMD10005.pdf (1.15 Mbytes)
Publishing Date
2012-09-26
 
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