Superconducting films with critical temperature of 39 K obtained from stoichiometric MgB2 targets

The oriented films of the MgB2 high-temperature superconductor are synthesized through the method of the laser sputtering of the MgB2 stoichiometric targets and subsequent thermal treatment of the Mg-B amorphous substance, deposited on the MgO (111) sublayer. The critical temperature of the films depended on the purity of the targets, used for the sputtering. It proved to be a success to achieve through the boron powder vacuum decontamination the low-level of the targets contamination and in the results to obtain the MgB2 films with the critical temperature, exceeding 39 K, and with the sharp inductive transition