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.

Abstract: In order to stably retain an oxide-based melt consisting essentially of yttrium or a lanthanoid element, barium, copper and oxygen at a prescribed temperature with no impurity contamination thereby preparing a large oxide crystal of high quality from the melt, an oxide melt consisting essentially of yttrium or a lanthanoid element, barium, copper and oxygen is stored in a first crucible, which in turn is held in a second crucible. The first crucible is made of a material which is an oxide of at least one element forming the melt having a melting point higher by at least 10.degree. C. than a melt retention temperature and causing no structural phase transition up to a temperature higher by 10.degree. C. than the aforementioned prescribed temperature, with solubility of not more than 5 atomic percent with respect to the melt in a temperature range from the room temperature to a temperature higher by 10.degree. C. than the melt retention temperature.

Abstract: A method of manufacturing an oxide superconductor by heating a raw material for an oxide superconductor composed of MBa.sub.2 Cu.sub.3 O.sub.7-.delta., where M represents at least a single element selected from a group of Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, to a temperature higher than a peritectic reaction temperature for melting the same and thereafter reducing the temperature to the peritectic reaction temperature to crystallize the oxide superconductor by peritectic reaction. A method of forming a dispersion solution of powder of a raw material for an oxide superconductor and applying the same on a substrate to prepare a thick film. A method of dipping a single crystal of M.sub.2 BaCuO.sub.5 in a molten solution of a mixture of BaCuO.sub.2 and CuO to form a thin film of an oxide superconductor on the single crystal. A method of manufacturing a bulky oxide superconductor by dipping a porous sintered material of M.sub.2 BaCuO.sub.5 in a molten solution of a mixture of BaCuO.sub.2 and CuO.