Synthesis and characterization of thallium-based 1212 films with high critical current density on LaAlO₃substrates

Abstract

Growth of epitaxial Cr-doped (Tl,Bi)-1212 films on LaAlO3substrates by pulsed laser deposition (PLD) and post-deposition annealing in static air has been achieved. The films exhibit a high transport Jc of over 1.5 × 106A cm-2at 77 K and self-field. Tc values measured by the four-probe method are in the range 94-100 K. ICP emission spectroscopy measurement shows a thallium deficiency, with about 0.15 atom bismuth per formula in the film. XRD -2 , and scans show that the dominant phase is 1212, with excellent epitaxy. The film surface has typical PLD morphology as analysed by SEM. TEM analysis found some inclusions in the film, and HREM found that three 1201 layers exist between the interface of 1212 phase and substrate.