Preparation of high-Tc superconductors under microgravity

High temperature superconductors are complicated materials consisting of at least four different elements. Both the growth of high quality single crystals as well as of fully epitaxial thin films is difficult and in certain cases may be even impossible. The same holds for film deposition on complicated surfaces. Furthermore nucleation and growth of these materials on crystalline and amorphous substrates is not well understood. We therefore propose to undertake a microgravity experiment with a modified sputter system to investigate the growth of thin films that could be purely epitaxial as well as the growth of high quality single crystals starting from small seed crystals. Some design considerations are discussed in this paper. (orig.)