Single crystal growth and LPE thin film process for RE-123 superconducting materials

Abstract

Fundamentals of solidification processing for high- T c superconductors (HTSC) and the progress of the crystal pulling and liquid phase epitaxy (LPE) processes were reviewed. RE-123 crystal is solidified by peritectic reaction with diffusion through the liquid. Based on this idea, a modified CZ (SRL-CP) method was developed for continuous single crystal growth. The large Nd123 single crystal, 25×25×25 mm 3 in size, was grown by optimizing the growth conditions. The high crystallinity in Y123 single crystal, which means monograin, was also realized by using Y123 seed crystals cut out of the best possible crystalline part of the single crystal grown separately. Additionally, the growth mechanism was discussed using the solidification model. In the LPE process, the highly aligned films in both c-axis and in-plane can be grown with the high superconducting characteristics, such as J c. The self-improvement mechanism for in-plane alignment due to preferential dissolution/growth was explained by the difference in the MgO/Y123 interface energies with different orientations.