摘要:
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. The second crucible is made of a material substantially causing neither melting nor chemical reaction with respect to the oxide-based melt, which can retain the melt more stably than the first material. Even if the melt overflows the first crucible, this overflow is suppressed by the second crucible. It is possible to prepare a crystal of an oxide superconductor such as YBa.sub.2 Cu.sub.3 O.sub.7-x (0.ltoreq.X.ltoreq.1) by the pulling method from the melt which is stored in the first crucible.
摘要:
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.
摘要:
A composite material comprising a bulky substrate of a Y-series 123 metal oxide crystal, and at least one layer provided on a surface of the substrate and formed of a crystal of a Y-series 123 metal oxide. The substrate may be produced by immersing a seed material in a liquid phase which comprises components constituting the metal oxide. The liquid phase contains a solid phase located at a position different from the position at which the seed material contacts the liquid phase. The solid phase provides the liquid phase with solutes which constitute the Y-series 123 metal oxide so that the solutes are transported to the position at which the seed material and the liquid phase contact, thereby permitting the Y-series 123 metal oxide to grow on the seed material as primary crystals and to obtain the bulky substrate. The layer of a Y-series 123 metal oxide may be formed on the substrate by a sputtering method, a vacuum deposition method, a laser abrasion method, a CVD method or a liquid phase epitaxy method.
摘要:
A superconductor comprising a compound of the formula (II):R.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.7-y1 (II)wherein not less than 40% of a crystal of the superconductor shows phase separation, and at (temperature, magnetic field) of (77�K!, O�T!) and (77�K!, 4�T!), a critical current density is not less than 10,000 A/cm.sup.2, which is obtained by heating a precursor which is a solid solution of the formula (I):R.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.7-y (I)wherein not more than 10% of a crystal of the solid solution shows phase separation, so that phase separation is formed in the crystals at a phase separation temperature, and introducing oxygen; and a superconductor comprising a compound of the formula (II):R.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.7-y1 (II)wherein not more than 10% of a crystal of the superconductor shows phase separation, and in a magnetic field of not less than 1�T! at a constant temperature of 77�K!, a critical current density is less than 10,000 A/cm.sup.2, which is obtained by introducing oxygen into the precursor (I) at a temperature less than the lower limit of the phase separation temperature. According to the method of the present invention, a superconductor having a high Jc or having different properties with respect to Jc, which is unobtainable by the conventional production method, can be obtained using the conventional materials.
摘要:
When a cuprate oxide LnBa.sub.2 Cu.sub.3 O.sub.7-x (Ln=Y, Pr or Sm; 0.30.ltoreq.x.ltoreq.1) single crystal is heated for growing a film epitaxially on the crystal or for smoothing a damaged surface of the single crystal, many large protrusions occur on the surface of the oxide single crystal substrate or the film. The smooth surface of the oxides becomes rugged by the protrusions. According to the present invention, however, the oxide substrate or the oxide superconductor film can be heated in an atmosphere including oxygen of a partial pressure between 50 mTorr and 200 mTorr to prevent the protrusions from originating on the surface of the heated oxides.
摘要翻译:当加热铜盐氧化物LnBa2Cu3O7-x(Ln = Y,Pr或Sm; 0.30 = x <1))单晶以在晶体上外延生长或用于平滑单晶的损伤表面时,许多 在氧化物单晶衬底或膜的表面上发生大的突起。 氧化物的光滑表面由突起变得坚固。 然而,根据本发明,氧化物基板或氧化物超导体膜可以在包括50mTorr至200mTorr之间的分压的氧的气氛中加热,以防止凸起源于加热的氧化物的表面。
摘要:
A composite material is disclosed which includes a substrate, an oriented film provided on a surface of the substrate and formed of a crystal of a Y123 metal oxide of the formula LnBa.sub.2 Cu.sub.3 O.sub.y wherein Ln stands for Y or an element belonging to the lanthanoid and y is a number of 6-7, and a layer of a Y123 metal oxide of the formula LnBa.sub.2 Cu.sub.3 O.sub.y wherein Ln stands for Y or an element belonging to the lanthanoid and y is a number of 6-7 formed on the oriented film.
摘要:
A superconducting laminated oxide substrate, which comprises a laminate a layer of a superconducting oxide crystal substrate made of a superconducting oxide single crystal or a superconducting oxide polycrystal and a layer of a reinforcing crystal substrate, prevents cracks from occurring in the superconducting oxide crystal substrate due to the heat treatment conducted for the purpose of forming an insulation film or a conductor film, and provides easy connectivity between electrodes and wiring formed on substrates located at upper and lower positions.
摘要:
There is provided a method for stably preparing rare earth (RE) 123 type oxide superconductors exhibiting outstanding superconductive properties in the atmosphere. In the method for preparing RE 123-type oxide superconductors by melting, cooling and solidifying a starting composition containing one or more than two kinds of RE such as Y, Sm, Nd, etc., and Ba, Cu and O as constituent elements to crystallize the RE 123-type oxide superconductors, the quantity of replacement between RE and Ba in "RE 123 crystals to be formed" is controlled by changing the initial constitution of the starting composition, for example, by changing the initial constitution to a more Ba-rich side than a composition on a 123-211 (or 422) tie line on a phase diagram to yield RE 123-type oxide superconductors in the atmosphere, which exhibits a critical temperature of 90 K or above and higher critical current density (Jc) in a magnetic field. A trace amount of Pt or CeO.sub.3 may be added to micronize the 211 (or 422) phase so as to further improve Jc.
摘要:
The generation of a reaction product is suppressed between a metallic substrate and plasma in depositing a ceramic intermediate layer on the metallic substrate in a process for depositing an oxide film on the metallic substrate by thermal plasma flash evaporation method. Thus, there is no reaction phase in the ceramic intermediate layer and the metallic substrate, and an intermediated buffer layer of only oxide ceramic is deposited on a flat surface of the metallic substrate. The intermediate ceramic layer is deposited in inert atmosphere of a low oxygen concentration at a temperature of less than 600.degree. C. for the metallic substrate. Then, a superconducting thin film is deposited on the ceramic intermediate layer.
摘要:
The present invention is aimed to provide a means for manufacturing a RE123 system oxide superconductor showing good superconductivity characteristics under atmospheric ambiance. In a method of manufacturing a RE123 system oxide superconductor by melting, cooling and solidifying material including rare-earth elements and a Ba--Cu--O solvent for crystallization such as by the crystal pulling method, examining beforehand the relationship between the melted material composition and the equilibrium liquid-phase composition and the crystal composition of the RE123 system oxide superconductor formed therefrom in atmospheric ambiance, and based on the result of said examination, adjusting the average composition of the material or the composition of the solvent (for example, setting the average composition of the material to an area where the superconductivity phase and the liquid phase coexist in equilibrium, and at the same time adjust the "Ba/Cu" ratio of the melted material to 3/5-1/1, or adjust the "Ba/Cu" ratio of the solvent inside the crystal pulling crucible to 3/5-1/1), in order to control the amount of mutual substitution between RE and Ba (control the value of x in RE123 system superconductor RE.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.7-d to 0-0.05 and the like) for crystallization.