Editing Superconductivity (section)

== Applications ==
{{Main|Technological applications of superconductivity}}
[[File:Flyingsuperconductor.ogg|thumb|Video of superconducting levitation of YBCO]]
Superconductors are promising candidate materials for devising fundamental circuit elements of electronic, spintronic, and quantum technologies. One such example is a superconducting diode,<ref>{{Cite journal |last1=Nadeem |first1=Muhammad |last2=Fuhrer |first2=Michael S. |last3=Wang |first3=Xiaolin |date=2023 |title=The superconducting diode effect |url=https://www.nature.com/articles/s42254-023-00632-w |journal=Nature Reviews Physics |language=en |volume=5 |issue=10 |pages=558–577 |bibcode=2023NatRP...5..558N |doi=10.1038/s42254-023-00632-w |issn=2522-5820 |s2cid=261976918 |url-access=subscription}}</ref> in which supercurrent flows along one direction only, that promise dissipationless superconducting and semiconducting-superconducting hybrid technologies.

[[Superconducting magnet|Superconducting magnets]] are some of the most powerful [[Electromagnet|electromagnets]] known. They are used in [[Magnetic resonance imaging|MRI]]/[[NMR]] machines, [[Mass spectrometer|mass spectrometers]], the beam-steering magnets used in [[Particle accelerator|particle accelerators]] and plasma confining magnets in some [[tokamaks]]. They can also be used for magnetic separation, where weakly magnetic particles are extracted from a background of less or non-magnetic particles, as in the [[pigment]] industries. They can also be used in large wind turbines to overcome the restrictions imposed by high electrical currents, with an industrial grade 3.6 megawatt superconducting windmill generator having been tested successfully in Denmark.<ref>Design and in-field testing of the world's first ReBCO rotor for a 3.6 MW wind generator" by Anne Bergen, Rasmus Andersen, Markus Bauer, Hermann Boy, Marcel ter Brake, Patrick Brutsaert, Carsten Bührer, Marc Dhallé, Jesper Hansen and Herman ten Kate, 25 October 2019, Superconductor Science and Technology.</ref>

In the 1950s and 1960s, superconductors were used to build experimental digital computers using [[cryotron]] switches.<ref>{{Cite web |last=Brock |first=David C. |date=2014-03-19 |title=Dudley Buck's Forgotten Cryotron Computer |url=https://spectrum.ieee.org/dudley-bucks-forgotten-cryotron-computer |access-date=2021-03-30 |website=[[Institute of Electrical and Electronics Engineers]] |language=en}}</ref> More recently, superconductors have been used to make [[Digital circuit|digital circuits]] based on [[rapid single flux quantum]] technology and [[RF and microwave filter|RF and microwave filters]] for [[mobile phone]] base stations.

Superconductors are used to build [[Josephson junction|Josephson junctions]] which are the building blocks of [[SQUID|SQUIDs]] (superconducting quantum interference devices), the most sensitive [[Magnetometer|magnetometers]] known. SQUIDs are used in [[Scanning SQUID microscope|scanning SQUID microscopes]] and [[magnetoencephalography]]. Series of Josephson devices are used to realize the [[International System of Units|SI]] [[volt]]. Superconducting photon detectors<ref>{{Cite journal |last1=Morozov |first1=Dmitry V. |last2=Casaburi |first2=Alessandro |last3=Hadfield |first3=Robert H. |date=2022-03-11 |title=Superconducting photon detectors |url=https://eprints.gla.ac.uk/263345/2/263345.pdf |journal=[[Contemporary Physics]] |volume=62 |issue=2 |pages=69–91 |doi=10.1080/00107514.2022.2043596 |issn=0010-7514 |s2cid=247422273}}</ref> can be realised in a variety of device configurations. Depending on the particular mode of operation, a [[superconductor–insulator–superconductor]] Josephson junction can be used as a photon [[detector]] or as a [[Electronic mixer|mixer]]. The large resistance change at the transition from the normal to the superconducting state is used to build thermometers in cryogenic [[Calorimeter|micro-calorimeter]] photon [[Detector|detectors]]. The same effect is used in ultrasensitive [[Bolometer|bolometers]] made from superconducting materials. [[Superconducting nanowire single-photon detector|Superconducting nanowire single-photon detectors]] offer high speed, low noise single-photon detection and have been employed widely in advanced [[Photon counting|photon-counting]] applications.<ref>{{Cite journal |last=Natarajan |first=C. M. |date=April 2012 |title=Superconducting nanowire single-photon detectors: physics and applications |url=https://iopscience.iop.org/article/10.1088/0953-2048/25/6/063001/meta |journal=Superconductor Science and Technology |language=en |volume=25 |issue=6 |pages=063001 |arxiv=1204.5560 |bibcode=2012SuScT..25f3001N |doi=10.1088/0953-2048/25/6/063001 |s2cid=4893642 |via=IOP Publishing}}</ref>

Other early markets are arising where the relative efficiency, size and weight advantages of devices based on [[high-temperature superconductivity]] outweigh the additional costs involved. For example, in [[Wind turbine|wind turbines]] the lower weight and volume of superconducting generators could lead to savings in construction and tower costs, offsetting the higher costs for the generator and lowering the total [[levelized cost of electricity]] (LCOE).<ref>{{cite journal |author=Islam |display-authors=etal |year=2014 |title=A review of offshore wind turbine nacelle: Technical challenges, and research and developmental trends. |url=http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2081&context=eispapers1 |journal=[[Renewable and Sustainable Energy Reviews]] |volume=33 |pages=161–176 |bibcode=2014RSERv..33..161I |doi=10.1016/j.rser.2014.01.085 |hdl-access=free |hdl=10453/33256}}</ref>

Promising future applications include high-performance [[smart grid]], [[electric power transmission]], [[Transformer|transformers]], [[SMES|power storage devices]], [[Fusion power|compact fusion power devices]], [[Electric motor|electric motors]] (e.g. for vehicle propulsion, as in [[Vactrain|vactrains]] or [[Maglev train|maglev trains]]), [[Magnetic levitation device|magnetic levitation devices]], [[Fault current limiter|fault current limiters]], enhancing spintronic devices with superconducting materials,<ref>{{cite journal |last1=Linder |first1=Jacob |last2=Robinson |first2=Jason W. A. |date=2 April 2015 |title=Superconducting spintronics |journal=Nature Physics |volume=11 |issue=4 |pages=307–315 |arxiv=1510.00713 |bibcode=2015NatPh..11..307L |doi=10.1038/nphys3242 |s2cid=31028550}}</ref> and superconducting [[magnetic refrigeration]]. However, superconductivity is sensitive to moving magnetic fields, so applications that use [[alternating current]] (e.g. transformers) will be more difficult to develop than those that rely upon [[direct current]]. Compared to traditional power lines, [[Superconducting transmission line|superconducting transmission lines]] are more efficient and require only a fraction of the space, which would not only lead to a better environmental performance but could also improve public acceptance for expansion of the electric grid.<ref>{{cite journal |author=Thomas |display-authors=etal |year=2016 |title=Superconducting transmission lines – Sustainable electric energy transfer with higher public acceptance? |url=http://cds.cern.ch/record/2267162/files/1-s2.0-S136403211501120X-main.pdf |journal=[[Renewable and Sustainable Energy Reviews]] |volume=55 |pages=59–72 |bibcode=2016RSERv..55...59T |doi=10.1016/j.rser.2015.10.041 |doi-access=free}}</ref> Another attractive industrial aspect is the ability for high power transmission at lower voltages.<ref>{{cite journal |author=Ren |first=Li |display-authors=etal |year=2009 |title=Technical and Economical Assessment of HTS Cables |journal=IEEE Transactions on Applied Superconductivity |volume=19 |issue=3 |pages=1774–1777 |doi=10.1109/TASC.2009.2019058 |s2cid=46117301 |doi-access=}}</ref> Advancements in the efficiency of cooling systems and use of cheap coolants such as liquid nitrogen have also significantly decreased cooling costs needed for superconductivity.