First Superconducting Transistor Created

holy_calamity writes "New Scientist reports that the first working superconducting transistor has been created, by researchers at the University of Geneva. Field effect transistors with zero electrical resistance would allow much faster operations. Only drawback is they need to be supercooled, something that may be addressed by improving the materials used."

Comments

Gift for understatement

[Raul654]

"Only drawback is they need to be supercooled, something that may be addressed by improving the materials used." - that last part is a bit of an understatement. We're still decades (centuries?) away from room temperature superconductors.

Re:Gift for understatement

[Sunthalazar]

Sure, but you don't have to do it at room temperature, either. There are superconductors at Liquid Nitrogen temps. Certainly most MRI machines use Liquid Helium temperature superconductors. They, of course, cost millions of dollars, but they are still used quite frequently.

IIRC, LN costs about the same as milk (~$3/gallon). If the rate of evaporation wasn't too great, it would just be an on-going charge. Say it was 1 gallon/month, would only cost you about $36/year.

Obviously LN distribution isn't up to par with electricity, but in the "closer" term it certainly would be feasible for "industrial" applications. Like running the Internet backbone routers.

Re:Gift for understatement

[Anonymous Coward]

so they are not used for very large magnets.

The wire drawing issue doesn't exactly help, but the main reason is Type I vs. Type II superconductors - the low-temperature metallic superconductors have a kind of superconductivity (Type I) that doesn't break down even in quite strong magnetic fields. However, the liquid-nitrogen (relatively-)high-temperature ceramic superconductors lose superconductivity (Type II) beyond a certain field strength. Which is very bad if you're using them for magnetic resonance imaging or particle acceleration (note how the LHC failure involved liquid helium cooling) which depend on generating and switching really strong magnetic fields generated by superconducting supermagnets, but doesn't matter so much if you're using them for computing or power transmission (with due care and attention to the strength of magnetic fields to avoid sudden catastrophic breakdown...).

Re:Gift for understatement

[Baron Eekman]

You're half right.

Two facts:
1) all superconductors superconduct better at lower temperatures
2) all superconductors superconduct better at lower magnetic fields

Basically, you can think of it as both temperature and magnetic field introducing a kind of disorder (causing Cooper pairs to break up, destroying superconductivity).

Type I superconductors don't allow any magnetic fields, Type II allow up to certain field strengths, depending on the material and also on temperature. (This is a 'competition' between the two important length scales in a superconductor: the coherence length--size of a Cooper pair; and the penetration depth--up to which distance a magnetic field still penetrates into the material).

In fact, the most important drawback of the high-temperature superconductors (up to about 140K), is that at those higher temperatures they don't allow for high magnetic field nor high current. Also, they're hard to produce on a large scale. Still it's commercially viable these days to use superconductors for current transport at liquid nitrogen temperatures.

Re:Liquid cooling?

[Anonymous Coward]

Hear that "whooshing" sound? It's not a fan.

Re:Liquid cooling?

[p0tat03]

Yes they do.