FABRICATION OF LARGE SINGLE-DOMAIN SM123 SUPERCONDUCTORS BY OCMG METHOD

Melt processing of Sm-Ba-Cu-O bulk superconductors was studied to find the optimum conditions for fabricating a large single-domain supercon ductor. First, the holding time at the maximum temperature for the par tial melting is important for the fabrication of a uniform bulk, espec ially for a large diameter. When the holding time at the maximum tempe rature during partial melting was not enough, two separated regions we re observed, which can be diminished by sufficient holding time. Next we studied the optimum conditions for grain growth, varying the temper ature gradient and cooling rate. The processing condition with which w e have succeeded in growing a single-domain SmBa2Cu3Oy (Sm123 hereafte r) with dimensions of 35 phi x 15 mm(2) is a temperature gradient of 7 .5 degrees C cm(-1) with a slow cooling rate of 0.33 degrees C h(-1). (C) 1998 Elsevier Science S.A. All rights reserved.