Crystal growth of (Bi, Pb)₂Sr₂Ca₂Cu₃O thin films fabricated via post annealing

Abstract

Post-annealing of superconducting Bi 2 Sr 2 Ca n-1 Cu n O x (BSCCO) thin films deposited by sputtering is essential for obtaining a single 2223 phase. However, optimum annealing temperature is limited to a very narrow range, needing to pass liquid phase for 2223 crystallization while not exceeding reevaporation point. In this study, we optimized annealing conditions and observed the crystal growth process. As a result, single phase 2223 thin films with critical temperature of 108 K were obtained at 850°C, while mixed phase thin films of 2223 and 2212 were grown above 855°C. This is due to the reevaporation of the thin film compounds, and these results reflect the recrystallization process after melting.

Preparation of high purity phase (Bi, Pb)-2223 superconducting films by sol–gel method

“…Moreover, the interface between the substrate and the superconducting layer was well-defined without any inter-diffusion, and the Bi-2223 film also started to nuclear and grow from Sr-O layer. Figure 7(f) displays the magnified image of the yellow rectangle box region in figure 7(d), in which the atoms were arranged in a sequence of BiO-SrO-CuO-Ca-CuO-Ca-CuO-SrO-BiO according to the (Bi, Pb)-2223 crystal structure with the lattice constant of 3.71 nm [31][32][33]. According to the interface atoms arrangement, the epitaxial orientation relationship between (Bi, Pb)-2223 film and LAO substrate is determined to be [110] Bi-2223 //[010] LAO and (001) Bi-2223 //(001) LAO .…”