Shaternik A. Regularities of formation by magnetron method of magnesium diboride superconducting films and multilayer structures for electronic devices.

The thesis is devoted to the solution of actual scientific and technical tasks connected with the establishment of regularities of magnesium-diboride-based superconducting films and multilayer structures for Josephson junctions formation using magnetron method. It has been determined for the first time that superconducting transition temperature, TC, of the films deposited on the cold (0001) plane of sapphire substrates increasing up to 36 K with the increase of annealing temperature up to 630 C and annealing duration up to 5 minutes due to improving in connectivity between grains of superconducting phase. The high critical current density, jc, can be obtained in the thin 140 nm films due to the formation of high density of homogeneously distributed nanoareas with enriched oxygen concentration (up to 16 at. %) which are commensurable with the coherence length (jc is 20% higher than for the known analogs). Based on the MgB2 films the multilayered structures (Josephson junctions) of MgB2-Si(W)-MoRe type with record values of characteristic voltage ICRN = 30-38 mV have been formed. This is attained due to formation of the barrier from the semiconducting silicon with metallic clusters of tungsten (concentration of W ~ 9 at. %) and due to realization of resonance-percolation charge transport via barrier and Andreev reflections at the superconducting surfaces of the Josephson junction. The obtained magnesium diboride films are promising for manufacturing on their base the superconducting band pass filters which give a possibility to increase the number of channels of mobile telephony in the limited frequency band. The formed Josephson junctions are perspective to form on their bases the superconducting devices, including SQUIDs, with the increased coefficient of the voltage-magnetic flux transformation.