Fabrication and morphology of (Hg,Re)-1212 thin films on LaAlO₃

Superconducting (Hg,Re)Ba₂CaCu₂O_y ((Hg,Re)-1212) thin films have been prepared on single crystal substrates of LaAlO₃ by reacting laser deposited ReBaCaCuO precursor films with CaHgO₂ in sealed quartz tubes. The effects of the deposition parameters such as laser fluence and substrate temperature, on surface morphology and microstructure were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM observations revealed that a granular structure was seen in the precursor films deposited at lower energy (less than 200 mJ) and disappeared at higher energy (250 mJ). SEM investigation on final reacted films showed that the precursor films deposited at 250 °C resulted in a well-connected and uniformly dense microstructure, whereas the films deposited at lower or higher temperatures were porous and non-uniform.