MgB2 thin films fabricated on Fe tape and effects of annealing on their properties

Abstract

Magnesium diboride (MgB2) thin films were fabricated on Fe tapes by an electron-beam evaporation method and post-annealed at 650 °C for 1–5 h. Appropriate post- annealing (1 h) resulted in a critical temperature (T c) of 34.4 K and infield critical current density (J c) of 0.20 MA cm−2 at 20 K under 6 T. Characterization suggests that annealing improves the crystallinity of the MgB2 thin film; however, Fe diffuses into the MgB2 layer when annealing for longer durations, which deteriorates the superconductivity. MgB2 thin films on Fe tape can be utilized in diverse superconducting applications under external magnetic fields.