Preparation and characterization of MgB2 thin film superconductors by using ultrasonic spray pryolysis(USP) and thermal evaporation (TBY) methods

In the scope of this thesis, the fabrication and characterization of MgB2 superconducting thin films have been studied using both ?Ultrasonic Spray Pyrolysis (Ultrasonic Nebulization)? and ?Thermal Evaporation? methods.Firstly, samples were produced by ultrasonic spray pyrolysis method. For the ultrasonic spray pyrolysis method, initially different compounds of Mg and B and different solvents have been used to prepare nominal MgB2 composition in liquid form. After then as prepared liquid solutions have been nebulized to obtain mist by using an ultrasonic nebulizer operating at 2.4 MHz 100 W and the mist obtained deposited onto the single crystal Al2O3, MgO and SrTiO3 substrates by using a carrier gas and so thin films have been fabricated.Secondly, the fabrication of MgB2 thin films were carried out by using thermal evaporation method. For the thermal evaporation method, Mg and B powder chemicals in particle size of 40-80 nm which were prepared using ultrasonic spray pyrolysis method previously and thermal evaporation system with double crucibles under 10-7 torr vacuum have been used to prepare thin film superconductors onto the single crystal Al2O3, MgO and SrTiO3 substrates.The superconductor thin film samples, prepared by using both system were then characterized by investigating the micro-structural and structural analysis, electrical properties, magnetic properties and calculating the critical current density (SEM-EDX, XRD, R-T, MR-T, M-H, Jc). Finally, productability of thin film MgB2 samples having minimum production cost and the best superconducting properties and their application to the technologies have been evaluated.Key words: Superconductivity, MgB2 alloys, thin films, Ultrasonic Spray Pyrolysismethod, Thermal Evaporation method