Durham scientists contribute to Superconductivity breakthrough
(29 October 2012)
A team of researchers including scientists from Durham University have made a breakthrough in superconductivity, the phenomenon which involves the transformation of certain materials, below a critical temperature, into a state which cannot be penetrated by magnetic fields and has no electrical resistance.
The team, a collaboration with colleagues from Oxford University and the ISIS facility, a leading centre for research in the physical and life sciences based in Oxfordshire, has shown that a new technique for synthesising superconductors results in a dramatic improvement in their useful properties.
Superconductivity is one of the most fascinating phenomena that occurs in nature and involves the transformation of a material to a state of matter similar to that of the Universe shortly after the Big Bang. Superconductors even contain particles whose physics is described by the famous Higgs mechanism that was recently demonstrated at the Large Hadron Collider in Geneva. The critical temperature below which superconducting properties switch on is usually very low, typically only ten or twenty degrees above absolute zero. The team's breakthrough, reported this week in the journal Nature Materials, involves taking the superconductor iron selenide (FeSe) which is formed from layers of iron and selenium and putting molecules between these layers. This results in a four-fold increase in the critical temperature.
Using a range of experimental techniques, the team have revealed the magnetic and superconducting properties of the new superconductor. This has included the use of neutrons to investigate the structure of the material, and subatomic particles called muons to probe the superconducting state.
Dr Tom Lancaster of Durham University's Department of Physics, who carried out the muon measurements, explained that "muons allow us to measure some of the key magnetic features of a superconductor which may provide a clue as to what causes superconductivity in these unusual materials."
It is hoped that the new paradigm for producing superconductors utilised in this work will lead to a further increase in the critical temperature.
Dr Lancaster said: "Although, at forty-three Kelvin, the critical temperature of our new material is still well below room temperature, there is an exciting possibility of raising the temperature still further by using this principle of incorporating molecules into layered superconducting materials."
Superconductors have many potential technological applications and may be used to make powerful electromagnets for maglev trains, loss-free power cables and sensitive electronic components such as the elements required to make a quantum computer.