Fabrication of double-sided Tl 2Ba 2CaCu 2O 8 thin films on 2-in. LaAlO 3 substrates by pulsed laser deposition and post-annealing

Abstract

Double-sided Tl 2Ba 2CaCu 2O 8 (Tl-2212) thin films have been prepared on 2-in. LaAlO 3 substrates by a two-step method in which Tl-free amorphous Ba 2CaCu 2O x precursor films were first deposited on the substrates by pulsed laser deposition and the subsequent thallination, crystallization and oriented growth of the superconducting Tl-2212 films were obtained in a long-duration annealing process in argon atmosphere at temperature around 720–740 °C. The films were characterized by means of X-ray diffraction, scanning electron microscopy and transport measurements. The results show that the as-prepared films are predominately single phase with c-axis perpendicular to the substrate surface, except for the presence of some submicron particles on the film surface. For the both sides of the films, the zero-resistance transition temperature T C0 is about 105 K and the critical current density J C is in excess of 10 6 A/cm 2. The microwave surface resistance R S is below 0.5 mΩ.