This may be very important. We have here a way to test for
superconductivity over a wide range of materials and their multiple variations
and various temperatures.
It also suggests that it will be
possible to establish single layer materials that may have conductivity turned
on through a mask to provide a superconductive circuit board. If this is not neat, then what is?
There is obviously plenty of lab
work to conduct to see where this all goes but the possibility is now
confirmed.
Light touch transforms material into a superconductor
14 Jan 11
Professor Andrea Cavalleri used laser light to transform a material
into a superconductor
A non-superconducting material has been transformed into a
superconductor using light, Oxford
University
One hundred years after superconductivity was first observed in 1911,
the team from Oxford , Germany
and Japan
‘We have used light to turn a normal insulator into a superconductor,’
says Professor Andrea Cavalleri of the Department of Physics at Oxford
University and the Max Planck Department for Structural Dynamics, Hamburg.
‘That’s already exciting in terms of what it tells us about this class of
materials. But the question now is can we take a material to a much higher
temperature and make it a superconductor?’
The material the researchers used is closely related to
high-temperature copper oxide superconductors, but the arrangement of electrons
and atoms normally act to frustrate any electronic current.
In the journal Science, they describe how a strong infrared laser
pulse was used to perturb the positions of some of the atoms in the material.
The compound, held at a temperature just 20 degrees above absolute zero, almost
instantaneously became a superconductor for a fraction of a second, before
relaxing back to its normal state.
Superconductivity describes the phenomenon where an electric current is
able to travel through a material without any resistance – the material is a
perfect electrical conductor without any energy loss.
But the question now is can we take a material to a much higher
temperature and make it a superconductor?
Professor Andrea Cavalleri
High-temperature superconductors can be found among a class of
materials made up of layers of copper oxide, and typically superconduct up to a
temperature of around –170°C. They are complex materials where the right
interplay of the atoms and electrons is thought to ‘line up’ the electrons in a
state where they collectively move through the material with no resistance.
‘We have shown that the non-superconducting state and the
superconducting one are not that different in these materials, in that it takes
only a millionth of a millionth of a second to make the electrons “synch up”
and superconduct,’ says Professor Cavalleri. ‘This must mean that they were
essentially already synched in the non-superconductor, but something was
preventing them from sliding around with zero resistance. The precisely tuned
laser light removes the frustration, unlocking the superconductivity.’
The advance immediately offers a new way to probe with great control
how superconductivity arises in this class of materials, a puzzle ever since
high-temperature superconductors were first discovered in 1986.
But the researchers are hopeful it could also offer a new route to
obtaining superconductivity at higher temperatures. If superconductors that
work at room temperature could be achieved, it would open up many more
technological applications.
‘There is a school of thought that it should be possible to achieve
superconductivity at much higher temperatures, but that some competing type of
order in the material gets in the way,’ says Professor Cavalleri. ‘We should be
able to explore this idea and see if we can disrupt the competing order to
reveal superconductivity at higher temperatures. It’s certainly worth trying!’
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