Abstract:
In a conventional method for pulling a single crystal, a neck having a smaller diameter has been formed in order to exclude dislocation induced in dipping a seed crystal into a melt. However, in pulling a heavy single crystal having a large diameter of 12 inches or more, the single crystal cannot be supported and falls. When the diameter of the neck is large enough to prevent the fall, the dislocation cannot be excluded and propagates to the single crystal. In the present invention, when the distance between the lowest end of the seed crystal and the melt is 10-100 mm, the seed crystal is caused to stop descending and is preheated. Then, by bringing the seed crystal into contact with the melt at a gradually decreased descent speed, dislocation is not induced to the single crystal and the single crystal is formed without a neck.
Abstract:
A production process of a thick-film tape-shaped RE-type (123) superconductor having a high critical current value. The production process has the steps of providing a composite substrate having Gd2Zr2O7 and CeO2 stacked in that order onto a Hastelloy substrate, coating a raw material solution prepared by dissolving a trifluoroacetate of Y and Ba and a naphthenate of Cu onto the composite substrate, heat treating the coated composite substrate by calcination, then subjecting the calcined assembly to intermediate heat-treatment at a temperature below the temperature of heat-treatment for superconductor production, and then heat treating the assembly in an argon gas atmosphere under conditions of highest heating temperature 760° C., water vapor partial pressure 13.5%, and oxygen partial pressure 0.09% for superconductor production to produce a tape-shaped RE-type (123) superconductor having a YBCO superconducting film having a thickness of more than about 2 μm.
Abstract:
A method of manufacturing a tape-formed oxide superconductor, in which a tape-formed wire material (6 in FIG. 1) is extended between a pair of reels (5a and 5b). Besides, a reactive gas is supplied form the gas supply ports of a reactive gas supply pipe (3a) vertically to the upper side film surface of the tape-formed wire material (6), so as to react the film body of this tape-formed wire material into a superconducting layer, while at the same time, a gas after the reaction is discharged from the gas discharge ports of discharge pipes (4a and 4b) for discharging the gas after the reaction. Likewise, the reactive gas is supplied vertically to the lower side film surface of the tape-formed wire material (6), so as to react the film body of this tape-formed wire material into a superconducting layer, while at the same time, the gas after the reaction is discharged from the gas discharge ports of discharge pipes (4c and 4d) for discharging the gas after the reaction. Even when the tape-formed wire material (6) is large in area, the tape-formed oxide superconductor has superconducting characteristics being uniform in it widthwise direction, and it can be manufactured at high speed.
Abstract:
A RE-type oxide superconducting wire having excellent angular dependence for magnetic field of Jc is obtained by finely dispersing magnetic flux pinning centers into a superconductor. A mixed solution which comprises a metal-organic complex solution including a metal element which composes a RE-type oxide superconductor whose Ba content is reduced and a metal-organic complex solution including at least one or more kinds of metals which are selected from Zr, Ce, Sn, or Ti which has a larger affinity for Ba is coated onto an intermediate layer of a composite substrate, and the assembly is then calcined to disperse artificially and finely oxide particles (magnetic flux pinning centers) including Zr. Thus, the angular dependence for magnetic field (Jc,min/Jc,max) of Jc can be remarkably improved.
Abstract:
Tape-shaped superconducting wires, and a superconducting coil formed from said wires, wherein a plurality of electrically separated superconducting film parts, each having a rectangular cross section and arranged in parallel, form parallel conductors, providing superconducting wires capable of containing losses incurred in the presence of alternating current (A/C). A superconducting coil is made by winding the superconducting wires, wherein the coil structure contains at least a part wherein perpendicular interlinkage magnetic fluxes acting among conductor elements of the parallel conductors by the distribution of magnetic fields generated by the superconducting coils cancel mutually in order to contain circulating current within the wires and to make shunt current uniform, thereby providing a low-loss A/C superconducting coil.
Abstract:
A continuous observation apparatus of magnetic flux distribution in which a long sample containing a superconducting material or magnetic material is transferred to an observation position and magnetic flux is observed sequentially at each of certain areas along a longitudinal direction of the sample is provided. A method of continuously observing magnetic flux by which a long sample containing a superconducting material or magnetic material is transferred to an observation position and magnetic flux is observed sequentially at each of certain areas along a longitudinal direction of the sample is also provided.
Abstract:
A method of manufacturing a tape-formed oxide superconductor, in which a tape-formed wire material (6 in FIG. 1) is extended between a pair of reels (5a and 5b). Besides, a reactive gas is supplied form the gas supply ports of a reactive gas supply pipe (3a) vertically to the upper side film surface of the tape-formed wire material (6), so as to react the film body of this tape-formed wire material into a superconducting layer, while at the same time, a gas after the reaction is discharged from the gas discharge ports of discharge pipes (4a and 4b) for discharging the gas after the reaction. Likewise, the reactive gas is supplied vertically to the lower side film surface of the tape-formed wire material (6), so as to react the film body of this tape-formed wire material into a superconducting layer, while at the same time, the gas after the reaction is discharged from the gas discharge ports of discharge pipes (4c and 4d) for discharging the gas after the reaction. Even when the tape-formed wire material (6) is large in area, the tape-formed oxide superconductor has superconducting characteristics being uniform in it widthwise direction, and it can be manufactured at high speed.
Abstract:
A rod 1 made of superconducting oxide is soaked in a molten normal conductor 2 to join the rod 1 and the normal conductor 2, whereby a superconducting oxide current lead is prepared. As a result, a contact resistance at the interface between the superconducting oxide and the normal conductor can be reduced. Consequently, Joule's heat at a current lead having a small cross sectional area can be suppressed low, which in turn realizes the reduction of the load on a freezer and the amount of evaporated cooling solvent, with respect to a superconducting coil.
Abstract:
Methods and apparatuses for pulling a single crystal. In a conventional method for pulling a single crystal, a neck having a smaller diameter has been formed in order to exclude dislocation induced in dipping a seed crystal into a melt. But in pulling a heavy single crystal having a large diameter of 12 inches or more, the single crystal cannot be supported and falls. When the diameter of the neck is large enough to prevent the fall, the dislocation can not be excluded and propagates to the single crystal. In the present invention, using an apparatus for pulling a single crystal having a laser beam generator or an incoherent light generating-inducing apparatus, the temperature of the front portion of the seed crystal is gradually raised by being irradiated with the laser beam or the incoherent light, and then, the seed crystal is dipped into the melt. As a result, the induction of the dislocation to the seed crystal caused by a thermal stress is prevented. Then, the single crystal is pulled without forming a neck. Therefore, a heavy single crystal can be pulled. The methods and the apparatuses for pulling a single crystal are used for pulling a single crystal ingot such as an upsized silicon single crystal.
Abstract:
A method of pulling a crystal of a metal oxide is disclosed, in which the growth of the crystal is performed in a liquid phase having a composition which is different from the metal oxide and which contains components constituting the metal oxide. The liquid phase is in contact with a solid phase located at a position separated from the position at which the crystal of the metal oxide grows. The solid phase has a composition different from that of the metal oxide and supplies components constituting the metal oxide to the liquid phase.