Enhancing Superconducting Properties of Thallium-Based Tl-1223 Thin Films through Optimized Rapid Thermal Annealing of Titanium Alloy Precursor Films on Lanthanum Aluminate Substrates

This paper shows the enhancements of a Tl-1223 high-temperature superconducting thin film prepared on lanthanum aluminate (LAO) substrates using an optimized rapid thermal annealing process. The annealing process of the precursor film was improved, and the effects  of different annealing conditions on the thalliation crystallization of the precursor film were investigated. A precursor film of the Tl-based high-temperature superconducting thin film was first prepared on the surface of the LAO substrate using the magnetron sputtering process, followed by annealing treatment in a rapid thermal furnace. X-Ray Diffraction (XRD) characterization showed that both the annealing temperature and the heating rate significantly affect the phase formation of the precursor film. Through annealing optimizations, films with a Tc of 115K and Jc of 2.2 MA/cm2 were achieved, demonstrating enhanced superconducting performance. By adjusting the parameters, a Tl-1223 superconducting thin film with a highly oriented c-axis can be fabricated. Scanning Electron Microscopy (SEM) observations indicated that the superconducting films with good crystalline states have smooth and intact surface morphology, and the critical transition temperature (Tc) of the superconducting films prepared was measured at about 115K in liquid nitrogen. The films’ crystallinity was gauged using Atomic Force Microscopy (AFM) for three-dimensional information.