Improvement of current density by texture andIc anisotropy inthin filament MgB2/Fe tapes

Abstract

Thin filament MgB2/Fe tapes have been made by the powder-in-tube technique using a precursor powder prepared bymechanical alloying and deformed by two-axial rolling. Increasing critical current density(Jc) in a parallel external magnetic field has been measured for a reduced filament thickness up to18.5 µm; this could be effective for future practical fine-filamentaryMgB2 conductors.This increase in Jc is attributed to an apparent improvement in texture introduced by rolling. Further increase inJc with reduction of filament size is limited due to chemical reactionat the filament/Fe interface during the final heat treatment at600 °C for 3 h. On the other hand, improved texture leads to a strong critical currentanisotropy, which increases with the reduced filament thickness and temperature. HighIc anisotropy can lead to an apparent reduction of the total magnet current due to the effectof the radial field component, as in the case of high temperature superconductingcoils.