Doping effects of nanoscale Fe particles on the superconducting properties of powder-in-tube processed MgB_2 tapes

摘要

The doping effects of nanoscale ferromagnetic Fe particles on the superconducting properties of MgB_2 tapes were investigated. Using ex situ and in situ powder-in-tube methods with doping from 0.1 to 2.4 wt percent Fe, Fe-sheathed MgB_2 tapes with a mono-core were prepared. The sample tapes were characterized using magnetization measurements and x-ray diffraction analysis. Irrespective of the fabrication method, no positive effects on the transition temperatures or irreversibility temperatures were obtained. Furthermore, the addition of nanoscale Fe particles to MgB_2 tapes yielded no improvements in the transport critical current properties of the MgB_2 tapes, but a slight indication existed of interaction between the magnetized particles and the flux-thread in the magnetization curves of the Fe-doped MgB_2 tapes.