Search results
Results From The WOW.Com Content Network
However, currently known high-temperature superconductors are brittle ceramics that are expensive to manufacture and not easily formed into wires or other useful shapes. [4] Therefore, the applications for HTS have been where it has some other intrinsic advantage, e.g. in: low thermal loss current leads for LTS devices (low thermal conductivity),
The table below shows some of the parameters of common superconductors. X:Y means material X doped with element Y, T C is the highest reported transition temperature in kelvins and H C is a critical magnetic field in tesla. "BCS" means whether or not the superconductivity is explained within the BCS theory.
Low temperature superconductors refer to materials with a critical temperature below 30 K, and are cooled mainly by liquid helium (T c > 4.2 K). One exception to this rule is the iron pnictide group of superconductors which display behaviour and properties typical of high-temperature superconductors, yet some of the group have critical ...
In the past, experimental AC synchronous superconducting machines were made with rotors using low-temperature metal superconductors that exhibit superconductivity when cooled with liquid helium. These worked, however the high cost of liquid helium cooling made them too expensive for most applications.
Metallic low-temperature superconductors with technical relevance 9.2 −264.0 NbTi [28] 4.21 −268.94 100 kPa Helium: Boiling point at atmospheric pressure (common cooling agent of low temperature physics; for reference) 4.15 −269.00 Hg [29] Metallic low-temperature superconductors 1.09 −272.06 Ga [29]
A substance with a high critical temperature will generally have a higher critical current at low temperature than a superconductor with a lower critical temperature. This higher critical current will raise the energy storage quadratically, which may make SMES and other industrial applications of superconductors cost-effective. [22]
The most famous ReBCO is yttrium barium copper oxide, YBa 2 Cu 3 O 7−x (or Y123), the first superconductor found with a critical temperature above the boiling point of liquid nitrogen. [10] Its molar ratio is 1 to 2 to 3 for yttrium, barium, and copper and it has a unit cell consisting of subunits, which is the typical structure of perovskites .
The most commonly used conventional superconductor in applications is a niobium-titanium alloy - this is a type-II superconductor with a superconducting critical temperature of 11 K. The highest critical temperature so far achieved in a conventional superconductor was 39 K (-234 °C) in magnesium diboride.