Scientists believe they are now within sight of seeing superconductivity - the elusive phenomenon of electricity flowing without resistance - at room temperatures, a feat that would revolutionise practically every sphere of modern technology, from underground cables to satellites.
New research promises the prospect of electricity transmission with virtually no loss of energy; of more sensitive medical instruments; of super- efficient trains that ride on frictionless magnetic tracks; and of far cheaper satellite communications.
Researchers at France's National Centre for Scientific Research near Paris say in the journal Science they appear to have achieved superconductivity at 250 degrees Kelvin (-23C), which is 117 degrees warmer than the previous record and a stone's throw in scientific terms from the goal of room-temperature superconductivity.
Ever since 'high temperature' superconductivity was discovered in 1986, scientists have achieved progressive improvements in superconducting temperatures, from 30K (- 243C) in 1986 to 93K (-180C) in 1987 and 127K (-146C) in 1988.
Some believed superconductivity research had reached an impasse as the previous best temperature recorded early this year was just 133K (-140C).
The latest breakthrough - if corroborated by other researchers - smashes this previous best dramatically. An editorial in Science says the work may have brought the prospect of room-temperature superconductivity much closer.
This would bypass the difficulty posed by needing to super-chill the electrical devices to well below freezing point. 'The dreamed of room-temperature superconductor could dodge that problem, helping to unlock a cornucopia of applications,' Science says.
One of the world's foremost experts on the phenomenon, Ted Geballe, of Stanford University in California, said room-temperature superconductivity was like hunting for a needle in a haystack.
'Before this work we didn't know there was a needle there. It's nice to know that there is a needle.'
The French team, led by Michel Lagues, achieved its breakthrough with a conducting material made of eight copper-oxygen layers sandwiched between layers of bismuth, strontium, calcium and oxygen atoms. They found electrical resistance was 100,000 times smaller.
Professor Gordon Donaldson, head of applied physics at the University of Strathclyde, said: 'If this is real, people will be very excited. The expectation of superconductors operating at room temperature is virtually certain.'
Professor Colin Gough, director of the superconducting centre at Birmingham University, said the benefits would be more efficient power generation, transmission and storage. 'If this research proves to be true, it would be absolutely amazing.'