Enhancing Phase Purity of CSD Bi-2223 Thin Films Through Protected Sintering Method

Pure Bi₂Sr₂Ca₂Cu₃O_x (Bi-2223) phase is hard to be achieved in Bi-2223 thin films fabricated by using chemical solution deposition (CSD) due to the volatilization of specific elements. Two protected sintering methods were proposed in this work to enhance the phase purity of CSD Bi-2223 thin films. One method is two deposited thin films stacked “face-to-face” (FTF) and then sintered. A “substrate/precursor film/precursor film/substrate” architecture was used during sintering instead of common “precursor film/substrate” architecture. The other method was named “sealed face-to-face” (SFTF). The FTF structure was buried in Bi-2223 powders and then sealed in a silver envelope before sintering. Different sintering temperature and sintering time were investigated in an 8% O₂ (N 2 balance) atmosphere. The volume fraction of Bi-2223 phase could be enhanced to 17% by using the FTF method, and 68% by using the SFTF method.