News

New material could cut future energy losses

(19 March 2009)

The crystal structure
of the superconducting
material

Scientists have altered the structure of a previously resistant material to allow it to superconduct electricity.

This is a discovery which could eventually aid power transmission to homes and businesses, and help cut global energy loss. The team from Durham University and the University of Liverpool have produced a material from a football-shaped molecule, called carbon60, to demonstrate how a superconductor – an element, compound or alloy that does not oppose the steady passage of an electric current – works at temperatures suitable for commercial use in cities and towns. The research, published in Science magazine and supported by the Engineering and Physical Sciences Research Council (EPSRC), will allow scientists to search for materials with the right chemical and structural ingredients to develop superconductors that could help reduce global energy losses in the future. The scientists pressed the material, in powder form, with a piston cylinder, and found that the atoms within the material’s structure rearranged themselves. The material then changed from an insulator to a conductor. Professor Kosmas Prassides, from Durham University said: “At room pressure the electrons in the material were too far apart to super-conduct and so we ‘squeezed’ them together using equipment that increases the pressure inside the structure. We found that the change in the material was instantaneous – altering from a non-conductor to a superconductor. This allowed us to see the exact atomic structure at the point at which superconductivity occurred.” Superconductors are considered as one of the world’s greatest scientific discoveries and play an important role in medical technology.They are widely used as magnets in magnetic resonance imaging (MRI scanners) which help scientists visualise what is happening inside the human body. Electric generators made with superconducting wire are far more efficient than conventional generators wound with copper, their efficiency can more than 99% and superconductors could be a vital part of high-speed computers in the future. Superconductors have been developed to function at high temperatures, but the structure of the material is so complex that scientists have yet to understand how they might be used to provide power to homes and companies. Prof Matt Rosseinsky, from Liverpool University’s Department of Chemistry, explains: “Superconductivity is a phenomenon we are still trying to understand and particularly how it functions at high temperatures. Superconductors have a very complex atomic structure and are full of disorder. We made a material that was a non-conductor at room temperature and had a much simpler atomic structure, to allow us to control how freely electrons moved and test how we could manipulate the material to super-conduct.” Prof Kosmas Prassides added: "Our research shows how superconductors work at the simplest level yet, how the transition from one state to another, from insulator (non-conductor) to a superconductor, proceeds. It will help us: to understand the important factors behind superconductivity, to unravel the complexities of the process and to develop its potential in the future." Timeline of superconductor research: 1911: As part of an experiment with solid mercury, Dutch scientist, Heike Kamerlingh Onnes, discovered that when mercury was cooled to low temperatures, electricity could pass through it in a steady flow without meeting resistance and losing energy as heat. 1933: German researchers Walter Meissner and Robert Ochsenfeld discovered that a superconducting material will repel a magnetic field. 1957: American physicists John Bardeen, Leon Cooper, and John Schrieffer propose their Theories of Superconductivity. 1962: Scientists develop the first commercial superconducting wire, an alloy of niobium and titanium. 1986: Alex Müller and Georg Bednorz from the IBM Research Laboratory in Rüschlikon, Switzerland create a brittle ceramic compound that superconducted at the highest temperature then known. 2003: The prototype Japanese Yamanashi Maglev train reached a speed of 361 mph