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Physics World Digest: January 2002 edition

December 20, 2001

Special issue: New frontiers in superconductivity
When physicists announced a year ago this month that a humble black powder called magnesium diboride is a "superconductor" - in other words, it loses all electrical resistance below a certain temperature - the news sparked a world-wide race to uncover the basic properties of this material, which had been sitting on chemists` shelves for decades. It was also the latest in a string of materials - including iron, single crystals of carbon-60 and even DNA - that physicists now realise can superconduct. The renaissance in superconductivity research is celebrated in this issue of Physics World.

Magnesium diboride in the spotlight
The big advantage of magnesium diboride over other "high-temperature" superconductors is that it is cheap to make and easy to process into wires. And because it superconducts at a relatively balmy -233ºC - a higher temperature than most superconductors, it can carry current without resistance using straightforward electrical refrigeration. Paul Canfield and Sergey Bud`ko describe how the materials could, for example, be used as a lightweight superconducting magnet for magnetic-resonance imaging (MRI) systems in hospitals. Meanwhile, Physics World finds out how one US company - Hyper Tech - is already making magnesium-diboride wires that could slash the cost of superconducting cables. (p. 29 & 8)
Contact: Paul Canfield, Department of Physics and Astronomy, Iowa State University, US (tel. +1 515 294 6270; fax +1 515 294 0689; e-mail canfield@ameslab.gov)
Contact: Mike Tomsic, Hyper Tech, Troy, Ohio, US (tel. +1 937 332 0348; fax +1 937 332 0989; e-mail tomsic@voyager.net)

Superconductors go organic
Most superconductors - including magnesium diboride - can be described by a theory that dates back to the 1950s. Known as BCS theory - after its inventors John Bardeen, Leon Cooper and Robert Schrieffer - it has proved to be one of the outstanding achievements of theoretical physics. Physicists have recently discovered however, that certain crystals made from carbon-based molecules show "exotic" forms of superconductivity that cannot be described by BCS. In particular, it turns out that superconductivity in these molecules can be induced - rather than destroyed - by magnetic fields. Meanwhile, Physics World finds out what the theory`s two surviving inventors are up to now. (p. 27 & 9)
Contact: John Singleton, Clarendon Laboratory, Oxford University, UK (tel. +44 (0)1865 272236; fax +44 (0)1865 272400; e-mail j.singleton1@physics.ox.ac.uk)

Magnetic superconductors
Superconductivity and magnetism do not make good bedfellows. Expose a superconductor to a high magnetic field and you can kill the superconducting current in its tracks. Jacques Flouquet and Alexandre Buzdin describe the recent stunning discovery of three materials that are both magnetic and superconducting. These strange materials have revealed problems with existing theories of magnetism and superconductivity that are likely to keep researchers busy for years to come. (p. 41)
Contact: Jacques Flouquet, CEA Gernoble, France (tel. +33 4 76 88 54 23; fax +33 4 76 88 50 98; e-mail flouquet@drfmc.ceng.cea.fr)

An enterprising role with Star Trek
Science advisor to Star Trek - it sounds like the ideal job for a physicist with an interest in science fiction. Physics World speaks to Andre Bormanis, who describes how he aims to keep the show as scientifically honest as possible. In one episode of the new series Enterprise, captain Jonathan Archer - played by actor Scott Bakula - is trapped in a vacuum for several minutes. Bormanis looked up air-force research and found that the best way to survive such conditions is not to hold your breath - but to breathe normally. "That helped Scott to play the scene and made it more believable," explains Chris Black, supervising producer for Enterprise. (p. 12)
Contact: Andre Bormanis (tel. +1 323 956 5973; e-mail bormanis@loop.com)

When off-the-bone means just that
There`s nothing worse than tucking into your "off-the-bone" chicken curry and biting on a nasty bone. Now, however, one company has developed an X-ray system that can automatically detect fragments of bone in fish and poultry fillets on a production line. The "Bonescan" system, developed by Birmingham-based Spectral Fusion Technologies, records the X-ray image of the fillets over a range of energies. It then analyses the images at high and low energy with a neural network - a computer program that has previously been "trained" using thousands of images to distinguish between good fillets and ones that need to be de-boned again by hand. (p. 21)
Contact: Mark Graves, Spectral Fusion Technologies, Birmingham, UK (tel. +44 (0)1675 466111; fax +44 (0)1675 467111; e-mail mark@spectralft.com)

Aristotle: the first physicist?
Ever since Galileo attacked Aristotle`s view of the world, the Greek philosopher`s ideas have been regarded as a barrier to scientific progress. Aristotle mistakenly thought, for example, that the Earth was the centre of the solar system and misunderstood various aspects of how bodies move. But Michael Rowan-Robinson now thinks it is time to restore Aristotle`s reputation. Crowning him the world`s first physicist, he argues that many of Aristotle`s scientific ideas still hold true and explains how his idea of uniform, ever-flowing time - which Einstein`s relativity dismissed - actually reappears in certain views of the universe. As Rowan-Robinson says: "We can surely not fail to take seriously someone whose scientific ideas are still alive after more than 2000 years." (p. 15)
Contact: Michael Rowan-Robinson, Department of Physics, Imperial College, London, UK (tel. +44 (0)20 7954 7530; fax +44 (0)20 7594 7541; e-mail mrr@ic.ac.uk)

Also in this issue:
Fusion company comes in from the cold (p. 6); US invests in nanotechnology (p. 10); Compromising peer review (p. 17); New vision of magnetic tunnelling (p. 22); Classical Wigner crystals move on (p. 24); Experimental attophysics comes of age (p. 25); Sensors fit for the road (p. 26)

Institute of Physics