Effect Of Technical Parameters On Component Phases And Properties Of Tl₂Ba₂CaCu₂O₈ Superconducting Thin Films

The purpose of this work is that preparing single-phase Tl2Ba2CaCu2O8 HTS thin film. Details of the fabrication were studied in the light of deeply understanding of current circumstances of superconductivity performed at home and abroad.First, we prepared amorphous BaCaCuO precursor thin films on single crystal LaAlO3(001) substrate by RF magnetron sputtering. Then Tl2Ba2CaCu2O8 HTS thin films were obtained by an ex situ post annealing.In the first step, effect of the target's components on properties of thin films was investigated. Influences of Tl2O partial pressure and thallination temperature on the component phases and properties of Tl2Ba2CaCu2O8 HTS thin films were studied in the second step of ex situ post annealing treatments.The obtained thin films were characterized by X-ray diffraction(XRD) θ-2θ scan. SEM and EDX were used for the films' morphology and compositional analysis. The temperature dependence of the resistance was measured by the standard four-probe technique.There are better performances in the films prepared by Ba2Ca2Cu3Ox target than by Ba2CaCu2Ox target. The single-phase Tl2Ba2CaCu2O8 HTS thin film was obtained with a Tc0 of 107K at the optimal Tl2O partial pressure and thallination temperature 750℃. On excursion from the optimal conditions, there exist some impurities in the resultant films resulting in a reduction in Tc0 and surface quality with change in the microstructure morphology.