THERMODYNAMICALLY CONTROLLED MELT PROCESSING TO IMPROVE BULK MATERIALS

High quality melt textured YBCO samples have been prepared on a modifi ed MTG route, a trapped magnetic field of 8.5 T at 51.5 K was measured in the gap of 1 mm in a mini-magnet from two YBCO cylinders (d = 26 m m, h = 12 mm). at 77 K, each single domain cylinder traps more than 60 0 mT and the levitation pressure of 15 N/cm(2) in a distance of 0.5 mm was achieved by a 0.4 T SmCo magnet, The thermodynamic background of the preparation method is outlined. A thermodynamic approach to contro l growth and stoichiometry y in the alternative material Nd1+yBa2-yCu3 Ox is discussed. Critical currents of 46 kA/cm(2) (77K) have been achi eved by a modified recipe.