The effects of the post-annealing temperature on the growth mechanism of Bi_2Sr_2Ca_1Cu_2O_(8+?) thin films produced on MgO (100) single crystal substrates by pulsed laser deposition (PLD)

摘要

The effects of post-annealing temperature were investigated on Bi_2Sr_2Ca_1Cu_2O_(8+?) thin films deposited on MgO (100) substrates by pulsed laser deposition (PLD). The structural and superconducting properties of the films have been determined by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature dependent resistivity (R-T), and DC magnetization measurements. The films which were deposited at 600 °C were post-annealed in an atmosphere of a gas mixture of Ar (93%) and O_2 (7%), at temperature ranging between 800 and 880 °C. This resulted in films which exhibited a single phase of 2212 with a high crystallinity (FWHM ≈ 0.16°) and texturing along the c-axis, perpendicular to the plane of the substrate. An optimum temperature of 860 °C was found for the post-annealing thermal treatment. The critical temperature, T_c, of the films was measured as 82 K and the critical current density, J_c, was calculated as 3 x 107 A/cm2 for the film annealed at 860 °C.