Researchers in Chicago and London have developed a method for controlling the properties of magnets that could be used to improve the storage capacity of next-generation computer hard drives.
Magnets that can readily switch their polarity are widely used in the computer industry for data storage, but they present an engineering challenge: A magnet's polarity must be easily switched when writing data to memory, but be difficult to switch when storing or reading it.
These conflicting requirements are typically met by heating and softening the magnet for saving data, then cooling and hardening the magnet for storage and reading. But now the University of Chicago's Daniel Silevitch and Thomas Rosenbaum and Gabriel Aeppli of the London Centre for Nanotechnology (a joint enterprise of University and Imperial Colleges London) have filed a patent on a method that avoids this complex heating operation. As the trio report in the Proceedings of the National Academy of Sciences, they can tune the softness of the magnet with the application of a small external magnetic field, which allows writing, storage and readout at a fixed temperature.
Citation: "Switchable hardening of a ferromagnet at fixed temperature," by D.M. Silevitch, G. Aeppli and T.F. Rosenbaum, Proceedings of the National Academy of Sciences, Early Edition, Jan. 29, 2010. www.pnas.org/cgi/doi/10.1073/pnas.0910575107
Funding: US Department of Energy and the United Kingdom Engineering and Physical Sciences Research Council.
About the London Centre for Nanotechnology
The London Centre for Nanotechnology is a UK-based, multidisciplinary research center forming the bridge between the physical and biomedical sciences. It was conceived from the outset with a management structure allowing for a clear focus on scientific excellence, exploitation and commercialization. It brings together two world leaders in nanotechnology, namely UCL and Imperial College London, in a unique operating model that accesses the combined skills of multiple departments, including medicine, chemistry, physics, electrical and electronic engineering, biochemical engineering, materials and earth sciences, and two leading technology transfer offices. Website: www.london-nano.com
Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. UCL is the fourth-ranked university in the 2009 THES-QS World University Rankings. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band Coldplay. UCL currently has more than 12,000 undergraduate and 8,000 postgraduate students. Its annual income is over £600 million. Website: www.ucl.ac.uk