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 (Tc) of 34.4 K and infield critical current density (Jc) 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.