{{Short description|Intermetallic chemical compound}} '''Niobium-germanium''' ('''Nb<sub>3</sub>Ge''') is an intermetallic chemical compound of niobium (Nb) and germanium (Ge). It has A15 phase structure.

<!-- Niobium–tin (Nb3Sn) ... is ... used industrially as a type II superconductor. .... It is more expensive than niobium-titanium (NbTi), but remains superconducting up to a magnetic flux density of 30 teslas [T] (300,000 G), compared to a limit of roughly 15 T for Nb3Ti. --> It is a superconductor with a critical temperature of 23.2 K.

Sputtered films have been reported to have an upper critical field of 37 teslas at 4.2 K.<ref>{{cite journal |title= Preparation of Nb<sub>3</sub>Ge films by chemical transport reaction and their critical properties |first= Gin-ichiro |last= Oya |author2=E. J. Saur |journal= Journal of Low Temperature Physics |volume= 34 |issue= 5–6 |year= 1979 |doi= 10.1007/BF00114941 |pages= 569&ndash;583 |url= https://dx.doi.org/10.1007%2FBF00114941 |bibcode=1979JLTP...34..569O|s2cid= 119846986 |url-access= subscription }}{{dead link|date=February 2020|bot=medic}}{{cbignore|bot=medic}}</ref>

==History== Nb<sub>3</sub>Ge was discovered to be a superconductor in 1973<ref>{{cite web |url= http://www.physicstoday.org/resource/1/phtoad/v26/i10/p17_s2?isAuthorized=no |archive-url= https://archive.today/20130415165724/http://www.physicstoday.org/resource/1/phtoad/v26/i10/p17_s2?isAuthorized=no |url-status= dead |archive-date= 2013-04-15 |title= Physics Today |date= October 1973 |publisher= American Institute of Physics }}</ref> and for 13 years (until the discovery in 1986 of the cuprate superconductors) it held the record as having the highest critical temperature.<ref>{{cite web |url= http://encyclopedia2.thefreedictionary.com/Superconducting+devices |publisher= TheFreeDictionary |accessdate= 2008-09-06 |title= Superconducting devices}}</ref>

It has not been as widely used for superconductive applications as niobium–tin or niobium–titanium.

==Related alloys== Niobium-germanium-aluminium has an upper critical field of about 10 teslas.<ref>{{cite book |title= Electromagnetic Suspension: Dynamics & Control |first= P. K. |last= Sinha |publisher= The Institution of Engineering and Technology |year= 1987 |isbn= 978-0-86341-063-5 |pages= 290 |url= https://books.google.com/books?id=DRdtKenSW1UC&q=niobium-germanium+superconductor&pg=PA9}}</ref>

==References== {{Reflist|30em}}

==External links== *[http://www.freepatentsonline.com/4336280.html US Patent 4336280: Method for continuous production of niobium-germanium layers]

{{Niobium compounds}}

Category:Germanium compounds Category:Intermetallics Category:Niobium compounds Category:Superconductors {{DEFAULTSORT:Niobium-germanium}}