Oxygenation Induced Cracking in YBCO Bulk Superconductors

Abstract

It is shown that the a/b- and c-macrocracks starts to form on the surface of YBCO bulk superconductors at the initial stage of oxygenation. Shortening of the Y123 c- and (a+b)/2-lattice parameters with increasing oxygen concentration induces tensile stresses on oxygenated layer and causes its cracking.