Fabrication of MgB₂ Thin Films Prepared on Aluminum Tapes and their Properties

Abstract

We prepared MgB₂ thin films on non-textured aluminum (Al) tapes using an electron-beam evaporation technique. Single phases of MgB₂ films with a c-axis and without biaxial crystal orientation were obtained with the critical temperatures (T_c) of 19-29.8 K, corresponding to the substrate temperature of 200-280°C. The magnetic field dependences of the critical current density (J_c) were measured at 4.2, 10 and 20 K in the field of 0-12 T applied parallel and perpendicular to the film surface. The J_c at 10 and 20 K in the self field were 3.1×10⁶ A/cm² and 1.2×10⁶ A/cm², respectively. J_c at 4.2 K exceeded 10⁶ A/cm² in the parallel and perpendicular fields of between 0 and 10 T. These results suggest that a MgB₂ coated conductor may be one of the most promising candidates for practical MgB₂ superconducting wires.