MgB2 thin films on Si(1 1 1) without a buffer layer prepared by e-beam evaporation

In this paper, improving transition temperature of MgB2 superconducting thin films on single crystal Si(1 1 1) substrates without a buffer layer was reported. MgB2 thin films were prepared by e-beam evaporation and two-step in situ annealing procedures. The resistance measurements showed that the critical temperature (Tc) was higher than 30 K on MgB2 thin films annealed for 30 min above 600 °C and could be enhanced slowly with annealing temperature increasing. For the MgB2 thin film annealed at 800 °C × 30 min, a critical transition temperature (Tc, at 50% onset resistance) of 33.6 K with a zero-resistance temperature (Tc0) of 32.8 K was obtained. The critical current density (Jc) was measured to 3.3 × 105 A/cm2 at 10 K and zero magnetic field.