Improvement of critical current density in Fe-sheathed MgB2 tapes by ZrSi2, ZrB2 and WSi2 doping

TL;DR

This study enhances the critical current density of Fe-sheathed MgB2 tapes by doping with ZrSi2, ZrB2, and WSi2, significantly improving performance especially with ZrSi2, without reducing the transition temperature.

Contribution

It demonstrates that doping MgB2 tapes with ZrSi2, ZrB2, and WSi2 improves critical current density and high-field performance, introducing effective pinning centers.

Findings

ZrSi2 doping increased Jc by up to 3.4 times at 4.2 K and 12 T.

Dopants did not significantly decrease the transition temperature.

WSi2 doping improved high-field Jc performance.

Abstract

Fe-sheathed MgB2 tapes were prepared through the in situ powder-in-tube technique by 5 at.% ZrSi2, ZrB2 and WSi2 doping, respectively. The doping effect of these compounds on the microstructure and superconducting properties of MgB2 tapes has been investigated by using x-ray diffraction, scanning electron microscope, transport measurements and DC susceptibility measurements. Compared to the undoped samples, Jc for all the doped samples were much improved; the best result in terms of Jc was achieved for ZrSi2 doping, by up to a factor of 3.4 at 4.2 K in magnetic fields up to 12 T. Moreover, these dopants did not significantly decrease the transition temperature. The Jc-B curves of WSi2-doped tapes show better performance in higher magnetic fields in comparison to undoped tapes, suggesting that pinning centers effective in a high-field region were possibly introduced.