High critical current densities in superconducting MgB2 thin films

Superconducting MgB2 thin films were prepared on Al2O3(0001) and MgO(100) s ubstrates. Boron thin films were deposited by the electron-beam evaporation followed by postannealing process with magnesium. Proper postannealing con ditions were investigated to grow good superconducting MgB2 thin films. The x-ray diffraction patterns showed randomly oriented growth of MgB2 phase i n our thin films. The surface morphology was examined by scanning electron microscope and atomic force microscope. Critical current density (J(C)) mea sured by transport method was about 10(7) A/cm(2) at 15 K, and superconduct ing transition temperature (T-C) was similar to 39 K in the MgB2 thin films on Al2O3. (C) 2001 American Institute of Physics.