Preparation and properties of new superconductor material MgB2
authors Marinha, D; Oliveira, FJ; Reis, MS; Costa, FM; Carrasco, MF; Araujo, JP; Sousa, JB; Vieira, JM; Amaral, VS
editors Vilarinho, PM
nationality International
journal ADVANCED MATERIALS FORUM III, PTS 1 AND 2
author keywords superconductors; hot isostatic pressing; critical current; MgB2
keywords HIGH-PRESSURE
abstract Bulk MgB2 samples were synthesized by hot isostatic pressing under pressures up to 200MPa at 950 degrees C. In these conditions, full densification of samples was obtained (similar to 98% of theoretical density). SEM, EDS and XRD analysis on final dense bodies were used to evaluate samples, and show increasingly better control over the amounts of secondary MgO (down to similar to 10%) and complete prevention of formation of MgB4 by using simple glass encapsulation techniques and addition of Mg(s) to the capsule. The samples display superconducting properties, including a narrow critical transition in electrical properties (Tc similar to 36-38K). Magnetic studies were performed, allowing the determination of the superconducting fraction and critical current density J(c) of the materials. Contrary to the Tc, the J(c) is quite sensitive to the processing and microstructure and values from 0.3 to 0.6x10(6) A/cm(2) are obtained at 10K. The reduction of J(c) with the applied magnetic field requires further improvements to reduce weak links.
publisher TRANS TECH PUBLICATIONS LTD
issn 0255-5476
year published 2006
volume 514-516
beginning page 333
ending page 337
web of science category Materials Science, Multidisciplinary
subject category Materials Science
unique article identifier WOS:000238056400069

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