99 results about "Superconducting transition temperature" patented technology

A conductor obtained by connecting a plurality of superconductors by normal conductivity or a conductor comprised of superconductors and normal conductors, said low resistance conductor using superconductors characterized in that an apparent specific resistance of said conductor at below a superconducting transition temperature of said superconductors is lower than the specific resistance of copper at that superconducting transition temperature.

The invention discloses a device and a method for measuring the superconducting transition temperature of a high temperature superconducting material, and belongs to the field of superconducting electronics. The method comprises the following steps that: the high temperature superconducting material to be measured is put into a closed vacuum chamber and is refrigerated by a compression refrigerating machine; a constant current source applies current to the high temperature superconducting material to be measured; a voltage measuring instrument sends the voltage data of the high temperature superconducting material to be measured to an acquisition and processing system; a temperature measuring instrument receives and displays the temperature of the high temperature superconducting materialto be measured, which is measured by a temperature sensor, and sends the temperature to the acquisition and processing system; and the acquisition and processing system stores the temperature data and the voltage data of the high temperature superconducting material to be measured, which are sent by the temperature measuring instrument and the voltage measuring instrument, and generates the change curve of the resistance of the high temperature superconducting material to be measured along with the temperature, so that the superconducting transition temperature of the high temperature superconducting material to be measured is determined. By the device and the method, the superconducting transition temperature of the high temperature superconducting material to be measured can be accurately measured, and certain practical value for the performance inspection of the prepared high temperature superconducting material is achieved.

To provide a superconducting X-ray detector capable of carrying out a measurement by a high energy resolution by restraining a reduction in a sensitivity by a self magnetic field. A superconducting X-ray detector comprising a temperature detector 6 for detecting a temperature change by heat generated when an X-ray is absorbed, and a heat link 3 for controlling a heat flow amount of escaping the generated heat to a support board i, wherein the temperature detector 6 comprises a heat conducting multilayer thin film, the superconducting X-ray detector is constituted by a structure of providing a superconductor layer 4 above the heat link 3 and providing an insulating member 2 between the superconductor layer 4 and the temperature detector 6, the superconductor layer 4 and the temperature detector 6 are connected by a superconducting wiring 7 and uses materials by which superconducting transition temperatures of the superconductor layer 4 and the superconducting wiring 7 are higher than a superconducting transition temperature of the temperature detector 6.

The present invention relates to a cryostat having a service neck for access to a superconducting magnet. In many cryogenic applications components, e.g. superconducting coils for magnetic resonance imaging (MRI), superconducting transformers, generators, electronics, are cooled by keeping them in contact with a volume of liquefied, the whole cryogenic assembly being known as a cryostat. In order to operate a superconducting magnet, it must be kept at a temperature below its superconducting transition temperature. A cryostat must provide access to the vessel containing the liquefied helium for the initial cooling of the magnet to its low operating temperature, for periodic refilling of systems where there is a loss of helium, and provide sufficient access whereby to enable operation and maintenance of the magnet. The present invention seeks to provide an access neck to a cryostat such as helium vessel with a minimum heat load and accordingly provides a cryostat assembly, wherein a service neck comprising at least one positive and one negative current lead is arranged such that one of the leads is formed by the neck tube wall and the space between a neck tube wall and the second current lead forms a gas path for venting and / or filling or other services.

The invention relates to a perovskite structure-based single-phase iron-based superconductive material and a preparation method thereof. The material has a two-dimensional laminar structure, and the composition is shown by the formula of Sr4V2O6Fe2As2. The preparation method of the material comprises the following steps of: preparing a SrAs precursor sample and an FeAs precursor sample; mixing the precursors, Sr0, V2O3, Fe and the like by using a solid-state chemical reaction method; and reacting at a high temperature to directly synthesize a perovskite layer-based iron-based superconductive material. Compared with other known iron-based superconductors, the material has higher bidimensionality. The material has electronic carrier characteristics, carrier concentration of 1,020 to 1,022 / cm<3> and superconductive transformation temperature of about 40K. An upper critical magnetic field of the material at a low temperature is estimated to be greater than 250 teslas, so that the material is probably applied to superconductive power transmission, strong magnetic field generation and the like. In addition, the material can also be used in a superconductive filter and the like. The preparation method is simple.

Described is a superconducting composition comprising an oxide complex of the formula [L1−xMx]aAbOy wherein L is lanthanum, lutetium, yttrium, or scandium; A is copper, bismuth, titanium, tungsten, zirconium, tantalum, niobium, or vanadium; M is barium, strontium, calcium, magnesium or mercury; and “a” is 1 to 2; “b” is 1; and “x” is a number in the range of 0.01 to 1.0; and “y” is about 2 to about 4. The oxide complexes of the invention are prepared by a solid-state reaction procedure which produces an oxide complex having an enhanced superconducting transition temperature compared to an oxide complex of like empirical composition prepared by a coprecipitation—high temperature decomposition procedure. With an oxide complex prepared by the solid-state reaction of the invention a transition temperature as high as 100°K has been observed even under atmospheric pressure.

The invention relates to a method for improving the superconducting performance of a Sn-added FeSe0.5Te0.5 superconductor. The method comprises the steps of mixing Sn powder and FeSe0.5Te0.5 powder in a weight ratio of 0.05: 1, and sufficiently grinding the mixture in an agate mortar for 20-30 minutes; and then preparing into a flake under the pressure of 6-8MPa, finally putting the flake into a high-temperature differential scanning calorimeter, heating to 600 DEG C under the protection of flowing high-purity argon, preserving the heat for 5-10 hours, and cooling to room temperature. A fact that a Sn-Se-Te liquid phase generated by reaction between Sn and FeSe0.5Te0.5 can accelerate the transformation from a non-superconducting phase to a superconducting phase is discovered for the first time and is favorable for forming a superconducting laminar structure so that the superconducting transition temperature of the structure is finally significantly improved, thus providing an important clue for optimizing a preparation process of an iron-based superconductor, illuminating an iron-based superconducting mechanism and promoting the development of the superconducting theory.

A cold head is disposed in an insulating container and cooled by a refrigerator. A superconductor is disposed in the insulating container, contacting the cold head, and is cooled to its superconduction transition temperature or lower by heat conduction. A magnetizing coil is disposed outside the insulating container for applying a magnetic field to the superconductor. Control is performed so that a magnetic field determined considering the magnetic field to be captured by the superconductor is applied. A pulsed magnetic field is applied to the superconductor a plurality of times. Each pulsed magnetic field is applied when the temperature of the superconductor is a predetermined temperature or lower. A maximum pulsed magnetic field is applied at least once in an initial or intermediate stage of the repeated application of pulsed magnetic fields. After that, a pulsed magnetic field equal to or less than the maximum pulsed magnetic field is applied. Pulsed magnetic fields are repeatedly applied while the temperature of the superconductor is lowered. A pulsed magnetic field is applied when the temperature T0 of a central portion of the superconductor is the superconduction transition temperature or lower and the temperature of a peripheral portion is higher than T0. The temperature of the entire superconductor is brought close to T0 to apply another pulsed magnetic field. The magnetizing coil faces at least one of two opposite sides of the superconductor to apply pulsed magnetic fields to the superconductor in its magnetization direction.

A thermally insulated vessel contains a thermal insulation barrier defining an upper compartment above the barrier and a lower compartment below the barrier. The compartments are interconnected by a passage to allow pressure equalization. High temperature superconductor is mounted within the lower compartment for immersion in the liquid cryogen. A cryogenic refrigerator has a cold head thermally coupled to the high temperature superconductor for maintaining the high temperature superconductor below a superconductive transition temperature. A temperature controller maintains a temperature of the liquid cryogen in the upper compartment at a temperature of at least a boiling point of the liquid cryogen at atmospheric pressure when the lower compartment and at least a portion of the upper compartment are filled with the liquid cryogen.

Described is a superconducting composition comprising an oxide complex of the formula [L1−xMx]aAbOy wherein L is lanthanum, lutetium, yttrium or scandium; A is copper, bismuth, titanium, tungsten, zirconium, tantalum, niobium, or vanadium; M is barium, strontium, calcium, magnesium or mercury; and “a” is 1 to 2; “b” is 1; “x” is a number in the range of 0.01 to 0.5 and preferably 0.075 to 0.5; and “y” is about 2 to about 4. The oxide complexes of the invention are prepared by solid-state reaction procedure which produce oxide complexes having enhanced superconducting transition temperatures compared to an oxide complex of like empirical composition prepared by a coprecipitation—high temperature decomposition procedure. With a solid-state reaction prepared oxide complex of the invention a transition temperature as high as 100° K has been observed even under atmospheric pressure.

The invention discloses a method for preparing iron selenium superconducting material by spark plasma sintering technology. The chemical formula of the iron selenium superconducting material is (FeSe)1(M)x, wherein the insulator M is one or more of SrTiO3, BaTiO3 and MgO, and the molar ratio of iron selenium (FeSe) to the insulator M is 1:x. The method for preparing the material includes: solid powder mixing, spark plasma sintering (SPS) and annealing. The powder of iron selenium and the powder of the insulator M are weighed respectively according to a certain molar ratio of 1:x, after mechanically grinding and mixing for a certain time, the mixed powder is subjected to spark plasma sintering at a suitable pressure and temperature, and then the sintered sample is annealed under suitable conditions to obtain (FeSe)1(M)x material. The material has a stable superconducting performance, and the superconducting transition temperature is between 10.10K and 13.44K. The material is not sensitive to the raw material ratio, and the value of x ranges from 0.2 to 15. Meanwhile, the material has a high upper critical field which can be up to 16.6T to 26.7T. Thereby the material can be applied in the fields of electric energy, superconducting magnets, biology, medical technology, communication, and microelectronics.