PREPARATION OF OXIDE CRYSTAL

摘要

PROBLEM TO BE SOLVED: To increase the crystal growth rate and prepare a large-sized oxide crystal of good quality in relation to a method for preparing the crystal for an oxide superconductor of a Y-based or a lanthanoid-based element by keeping the atmosphere for growing the oxide crystal under a higher pressure than oxygen partial pressure in the atmospheric air. SOLUTION: The atmosphere for growing an oxide crystal having a structure of R1+x Ba2-x Cu3 O7-z [R is Y or a lanthanoid-based element; 0<=(x)<=1; 0<=(z)<=1] is regulated so as to provide >=0.8atm partial oxygen pressure. A crystal of Y123 (YBa2 Cu3 O7-x ) is prepared by using an apparatus in the figure. Y2 BaCuO5 is placed in the lower part of a crucible 6 made of a sintered compact of Y2 O3 . Barium carbonate is mixed with copper oxide so as to afford 3:5 molar ratio of Ba to Cu and the resultant mixture is then calcined to provide a substance, which is placed in the upper part of the crucible and used as a raw material for a melt 4. Supporting columns 7 made of an MgO single crystal are stood in a dish 8 made of Al2 O3 and Ag 9 is placed therein. The crucible 6 is then placed on the dish 8. Oxygen is introduced from an introduction port 14 is regulate the oxygen concentration at >=95%. The interior of an airtight chamber 13 is heated at >=1020 deg.C with a heater 11 to carry out the crystal growth while rotating the seed crystal 2.