High-temperature superconductors: The mystery is being unravelled

Posted by Rick C. Hodgin

Chicago (IL) - Scientists from Queen Mary, University of London, and the University of Fribourg in Switzerland, have reportedly discovered that magnetism is involved behind the scenes in high temperature superconductors. The team has been studying two different types of materials used for relatively high temperature superconductors. They believe with continued study the precise mechanisms in place can be identified and applied to an even higher temperature class of materials, now making the ultimate dream of room-temperature superconductors now more possible than ever.





Dr. Alan Drew of Queen Mary's Physics department published his work in Nature Materials. Dr. Drew states that a new class of oxypnictides, high-temperature superconductors, exhibit "some striking similarities with the previously known copper-oxide high temperature superconductors - in both cases superconductivity emerges from a magnetic state."



Superconducting states allow materials to conduct electricity with no electrical resistance. In addition, they reflect magnetic fields applied to them. The materials are able to wield huge numbers of electrons, thereby creating extremely powerful electromagnet applications, but without melting down as happens in non-superconductive materials, like copper.



The reason we have to use a certain gauge wire for our homes, or car batteries, or speakers, or for any conventional application is because that much semi-conductive mass is required to allow all electrons to flow through without heating up the wire, increasing resistance, diminishing signal strength and ultimately melting. Were room-temperature superconducting wires available, nuclear power stations could be connected to wires the size of fiber-optics strands, with zero electrical loss over thousand-mile runs. It would literally change the face of our world.



Dr. Drew said:

"Last year, a new class of high-temperature superconductor was discovered that has a completely different make-up to the ones previously known - containing layers of Arsenic and Iron instead of layers of Copper and Oxygen. Our hope is that by studying them both together, we may be able to resolve the underlying physics behind both types of superconductor and design new superconducting materials, which may eventually lead to even higher temperature superconductors."



Professor Bernhard, a colleague from the University of Fribourg, said:
"Despite the mysteries of high-temperature superconductivity, their applications are wide-ranging. One exciting applications is using superconducting wire to provide lossless power transmission from power stations to cities. Superconducting wire can hold a much higher current density than existing copper wire and is lossless and therefore energy saving."



Still difficult and prone to error, but useful

Though obtaining superconducting material is somewhat difficult, as is using them in commercial applications, superconducting magnets have operated in modern society at very low temperatures for years in devices like MRIs and MagLev trains (and the Caterpillar Drive system in The Hunt for Red October's Russian submarine). They were also supposed to operate correctly on the Large Hadron Collider (LHC) at CERN. However, a failure in the liquid helium system (cooling the superconductors to a temperature of about 3 degrees Kelvin), caused a magnet to exceed its superconducting temperature resulting in a meltdown and a variation in the LHC's magnetic field along its 27km particle path. This failure resulted in a high-energy stream of particles colliding with the device's innards, instantly eroding it away to nothing and ultimately causing a very expensive and costly (in time) repair.



It will now reportedly be late Fall, 2009 before LHC goes back online with scientific collisions at full energy.