Carbon nanotubes effects on the relaxation properties and critical current densities of MgB 2 superconductor

Addition of nonsuperconducting phases, such as carbon nanotubes, can modify the superconducting properties of MgB 2 samples, improving the critical current density and upper critical field. A full understanding of the flux creep mechanism involved is crucial to the development of superconducting mag...

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Autores principales: Pasquini, G., Serquis, A., Moreno, A.J., Serrano, G., Civale, L.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00218979_v114_n2_p_Pasquini
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Sumario:Addition of nonsuperconducting phases, such as carbon nanotubes, can modify the superconducting properties of MgB 2 samples, improving the critical current density and upper critical field. A full understanding of the flux creep mechanism involved is crucial to the development of superconducting magnets in persistent mode, one of the main thrusts for the development of MgB 2 wires. In this paper we present a creep study in bulk MgB 2 samples, pure and with different amounts of carbon nanotubes additions. We conclude that the most consistent picture at low temperatures is a single vortex pinning regime, where the correlation length is limited by the grain size. We introduce a novel analysis that allows us to identify the region where the Anderson-Kim model is valid. © 2013 AIP Publishing LLC.