Superconducting glass-ceramic rods in BiCaSrCu2Ox prepared by crystallization under a temperature gradient

Superconducting BiCaSrCu2Ox glass rods and coils were successfully prepared by pumping up the melt at 1150 °C into SiO2 or Pyrex glass tubes. After the outer glass tubes were removed, the resultant glass rods up to 30 cm long were crystallized under a temperature gradient of 30 °C/mm without deforming and cracking. The Tc (onset) and Tc (zero) of the resulting glass-ceramic rods were ∼80 and 62 K, respectively.