Superconductivity and x-ray photoemission study of MgB₂ thin films

Highly c-axis oriented MgB₂ thin films with T_c^onset of 39.6K were fabricated by magnesium diffusing into pulsed-laser-deposited boron precursors. The estimation of critical current density J_c, using hysteresis loops and the Bean model, has given the value of 10⁷ A/cm² (15 K, 0 T), which is one of the highest values ever reported. The x-ray photoemission study of the MgB₂ thin films has revealed that the binding energies of Mg 2p and B 1s are at 49.4 eV and 186.9 eV, which are close to those of metallic Mg and transition-metal diborides, respectively.