DocumentCode
1241691
Title
The influence of structural defects on intra-granular critical currents of bulk MgB2
Author
Serquis, A. ; Liao, X.Z. ; Civale, L. ; Zhu, Y.T. ; Coulter, J.Y. ; Peterson, D.E. ; Mueller, F.M.
Author_Institution
Supercond. Technol. Center, Los Alamos Nat. Lab., NM, USA
Volume
13
Issue
2
fYear
2003
fDate
6/1/2003 12:00:00 AM
Firstpage
3068
Lastpage
3071
Abstract
Bulk MgB2 samples were prepared under different synthesis conditions and analyzed by scanning and transmission electron microscopy. The critical current densities were determined from the magnetization versus magnetic field curves of bulk and powder-dispersed-in-epoxy samples. Results show that through a slow cooling process, the oxygen dissolved in bulk MgB2 at high synthesis temperatures can segregate and form nanometer-sized coherent precipitates of Mg(B,O)2 in the MgB2 matrix. Magnetization measurements indicate that these precipitates act as effective flux pinning centers and therefore significantly improve the intra-grain critical current density and its field dependence.
Keywords
critical current density (superconductivity); flux pinning; grain boundary segregation; magnesium compounds; magnetisation; scanning electron microscopy; transmission electron microscopy; type II superconductors; Mg(B,O)2; MgB2; critical current densities; effective flux pinning centers; field dependence; high synthesis temperatures; intra-grain critical current density; intra-granular critical currents; magnetization; magnetization measurements; nanometer-sized coherent precipitates; powder-dispersed-in-epoxy; scanning electron microscopy; segregate; slow cooling process; structural defects; transmission electron microscopy; Cooling; Critical current; Critical current density; Density measurement; Magnetic analysis; Magnetic fields; Magnetization; Scanning electron microscopy; Temperature; Transmission electron microscopy;
fLanguage
English
Journal_Title
Applied Superconductivity, IEEE Transactions on
Publisher
ieee
ISSN
1051-8223
Type
jour
DOI
10.1109/TASC.2003.812093
Filename
1212270
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