Enhanced surface morphology of Bi2Sr1.8In0.2CaCu2O8+δ films via short-duration annealing

Abstract

In this study, we examined the surface and structural properties of pure and indium-doped Bi-2212 thin films synthesized via sedimentation deposition, followed by post-annealing durations of either 0 hours (RTA only) or six hours. We focused on how optimal indium doping (x = 0.2) and short-duration annealing of six hours affect the films' structural and surface characteristics. We observed a significant improvement in the surface uniformity and grain structure of the indium-doped samples compared to pure Bi-2212. A two-step heat treatment process comprising a high-temperature RTA at 990°C followed by a six hour post-annealing at a lower temperature was employed to enhance surface morphology, facilitating grain growth during the post-annealing stage face morphology. X-ray diffraction (XRD) analysis confirms that all samples preserve the Bi-2212 phase, with the doped samples exhibiting crystallinity. Electrical characterization shows superconducting transitions, with T_c,onset ranging from 96 K to 99 K; however, superconductivity was only observed in both pure and doped samples after six hours of post-annealing.