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Aspect ratio and temperature effect on the I c anisotropy in situ MgB 2 tapes

2006; IOP Publishing; Volume: 19; Issue: 6 Linguagem: Inglês

10.1088/0953-2048/19/6/010

1361-6668

P Kováč, I Hušek, T Melíšek,

Iron-based superconductors research

Single core MgB2/Fe and MgB2/Nb composite tapes of different aspect ratios (width to thickness—b/a) were prepared by an in situ process. Critical currents measured in parallel and perpendicular field directions revealed that Ic anisotropy increases with the tape aspect ratio b/a and also with applied temperature T. The effect of aspect ratio is saturated for b/a>5, but increasing the temperature systematically increases Ic anisotropy. Large Ic anisotropy makes the application of flattened MgB2 composite tapes for windings more problematic. The application of a Nb inner sheath and nano-sized additions into MgB2 reduced the anisotropy effectively.