News

Durham and Oxford join forces in new approach to Synthesising Superconductors

(1 November 2012)

A team of scientists from Oxford and Durham Universities, in collaboration with researcher at the ISIS facility, Oxfordshire
have demonstrated that a new approach to 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, below some critical temperature, to a state of matter which cannot be penetrated by magnetic fields
and which has no electrical resistance. Superconductors even contain particles whose physics is described by the famous Higgs mechanism
that was recently demonstrated at the LHC. This 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, 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."

Article: Enhancement of superconducting transition temperature of FeSe by intercalation of a molecular spacer layer

Authors: Matthew Burrard‐Lucas, David G. Free, Stefan J Sedlmaier, Jack D Wright, Simon J Cassidy,
Yoshiaki Hara, Alex J Corkett, Tom Lancaster, Peter J Baker, Stephen J Blundellb and Simon J Clarke

Journal:Nature Materials

DOI: 10.1038/NMAT3464