Improved growth of large YBCO single crystals

A new crystal pulling process was developed to produce large YBCO (Y123) single crystals under 1 atm oxygen pressure at a high growth rate, 1.5-2.5 times higher than that in air. A large crystal, 19.8 x 19.5 mm(2) in the a-b plane and 16.5 mm in thickness, was obtained. It is clear that a high oxygen partial pressure played a significant role in increasing the growth rate. The superconducting transition temperature T-c was measured to be 92.7 K for an oxygenated sample.