Synthesis of MgB₂ films on Hastelloy-C276 tape with Al₂O₃/Y₂O₃/MgO/LaMnO₃ buffer layers by magnetron sputtering in co-evaporation mode

This study presents the initial results of developing a technology for synthesizing a flexible superconducting magnesium diboride composite on a Hastelloy ® -C276 TM substrate coated with Al 2 O 3 /Y 2 O 3 /MgO/LaMnO 3 buffer layers. The superconducting composite was deposited by magnetron sputtering from two Mg and B targets, followed by vacuum annealing at various substrate temperatures ranging from 400 °C to 700 °C. The superconducting transition temperature T c ≈ 22 K, with a transition width Δ T ≈ 1 K, and critical current J c ≈ 500 kA cm −2 ( T = 5 K, H = 2 T) and J c ≈ 11 kA cm −2 ( T = 15 K, H = 2 T) at the optimal annealing temperature of 400 °C.