Method for preparing an oxide crystal

Abstract

In order to prepare a large yttrium or lanthanoid based oxide superconductor crystal of higher quality, a method and an apparatus which can stably control the shape of a pulled crystal and stably maintain growth of the crystal from a melt are provided. A crystal of an oxide having a structure of RBa.sub.2 Cu.sub.3 O.sub.7-X (R: yttrium or lanthanoid element, 0.ltoreq.X.ltoreq.1) is pulled from a raw material melt which is stored in a crucible by a rotary crystal pulling shaft. During such pulling, a position of the surface of the raw material melt is measured with time to obtain a lowering speed of the surface in a direction substantially parallel to the crystal pulling direction, for adjusting the lifting speed of the crystal pulling shaft by this lowering speed.

Dependencies are inferred from the claim text.