Stripes 'play key role' in superconductivity

Mar 21, 2011
Neutron scattering intensity maps of the magnetic excitation spectrum of La5/3Sr1/3CoO4.

(PhysOrg.com) -- Fluctuating magnetic stripes could be the cause of the mysterious hourglass-shaped magnetic spectrum found in high temperature superconductors, according to new research.

Scientists at Oxford University and the Institut Laue-Langevin have used to probe the magnetic ‘glue’ thought to produce high temperature superconductivity and have identified stripes of magnetic moments and charge as the cause of a strange hourglass-shaped magnetic spectrum. Their findings, reported in Nature, are a step forward in the search for a model of high temperature superconductivity.

Current research into the origins of high temperature superconductivity found in a large class of copper oxide compounds centres on the motion of atomic magnetic moments. Fluctuations of these moments are believed to create an attractive force (a sort of magnetic ‘glue’) which binds electrons in pairs and allows them to move around unimpeded giving rise to superconductivity.

Recent debate has focused on the cause of an unusual hourglass shape found in the spectrum of these magnetic fluctuations. The origin of this pattern, which is found in many if not all high temperature , is thought to relate to an alternating pattern of spin and charge stripes found within the atomic layers but so far it has been hard to prove a link between the two phenomena.

The researchers instead turned their attention to an insulating cobalt oxide with a similar magnetic stripe pattern. Using neutron scattering at the ILL the scientists measured the atomic-scale fluctuations in its magnetism and uncovered the same hourglass pattern in the data. Their results provide strong evidence that magnetic stripes are the cause of the hourglass spectrum and play an important role in high temperature superconductivity.

‘Our cobalt oxide compound is a magnetic look-alike for the ,’ said Professor Andrew Boothroyd of Oxford University’s Department of Physics, who led the work at Oxford. ‘Its lack of mobile electrons prevents it from becoming superconductive, allowing us to use neutron scattering to look in detail at nano-scale fluctuations in the magnetic motion without the complicating effects of superconductivity. The experiment allows us to isolate the source of the much-debated hour-glass spectrum.’

A report of the research, ‘An hour-glass magnetic spectrum in an insulating, hole-doped antiferromagnet’, is published in this week’s Nature.

Explore further: Quantum mechanics to charge your laptop?

More information: Nature, Volume 471, Pages: 341–344, 17 March 2011. www.nature.com/nature/journal/… ull/nature09902.html

Related Stories

New property in warm superconductors discovered

Nov 17, 2010

(PhysOrg.com) -- Led by Simon Fraser University physicist Jeff Sonier, scientists at TRIUMF have discovered something that they think may severely hinder the creation of room-temperature (37 degrees Celsius) superconductors.

Many roads lead to superconductivity

Sep 10, 2010

Since their discovery in 2008, a new class of superconductors has precipitated a flood of research the world over. Unlike the previously familiar copper ceramics (cuprates), the basic structure of this new class consists ...

The Unusual Insulating Properties of a Superconductor

Mar 09, 2006

Since their discovery, high-temperature superconductors, a class of remarkable materials that conduct electricity with almost zero resistance, have perplexed scientists. Despite many, many studies, how these ...

Recommended for you

Quantum mechanics to charge your laptop?

18 hours ago

Top scientists from UC Berkeley and MIT found the expertise they lacked at FIU. They invited Sakhrat Khizroev, a professor with appointments in both medicine and engineering, to help them conduct research ...

User comments : 0