Double crucible method for the growth of large superconducting YBCO single crystals

In this paper we report an effective procedure for the growth of large superconducting YBCO single crystals by using a double crucible method which facilitates detachment of the as-grown crystals from flux. As-grown crystals with dimensions up to 5 × 5 mm 2 have been obtained. The Superconducting transition occurs at about 90 K. The growth principle is based on the melt growth and phase separation method. We find that by using BaO 2 instead of BaCO 3 as raw material, the quality of as-grown crystals was much better and the superconducting transition temperature was a few degrees higher than in case of using BaCO 3.