The crystal growth of Y-Ba-Cu-O by laser floating zone melting

The crystal growth of Y-Ba-Cu-O is explored by means of laser-heated pedestal growth (LHPG), which is a new crucible-free floating zone technology for growing oxide crystals from the melt. The result shows that the superconducting phase of YBa 2 Cu 3 O 7-x melts incongruently, and is separated into two phases of (Y 2 BaCuO 5 and BaCuO 2 ) because of a peritectic reaction at 1010 degrees C during solidification. However, an oriented crystal in which the two phases coexist can be obtained by controlling the growth rate, and then may be transformed into superconductor with T c above 90 K; such a crystal presents certain textural features following suitable heat treatment. The crystal structure and orientation after solidification and heat treatment are studied with the help of X-rays on electron microprobe and on optical microscope.