Press Release, 23 November 2007
A technique for controlling the magnetic properties of a commonly used blue dye could revolutionise computer processing power, according to research published recently in Advanced Materials. Scientists have demonstrated that they can control the properties in a dye known as Metal Phthalocyanine, or MPc, with the use of magnetism. Though this technology is still in its infancy, the researchers claim that the ability to control the magnetic properties of MPc could have the potential to dramatically improve information processing in the future.
iPods, CD read/writers, and other electronic devices already use magnetism as a system for signalling to process and store information. Current technology, however, has limitations. According to Moore’s Law - a theory for describing the historical trend of computer hardware development – computer technology will eventually reach a ‘dead end’ as options for shrinking the size and increasing memory run out.
Image 1: Dr Sandrine Heutz
Dr Sandrine Heutz, from Imperial College London’s Department of Materials, and other scientists from the London Centre for Nanotechnology, believe results from recent experiments with MPc could provide the answer.
MPc include carbon, nitrogen and hydrogen and can also contain a wide range of atoms at its centre. In their work they used either a copper or manganese metal atom at its centre. Scientists first observed MPc in 1907 and it has been used ever since as a dye in textiles and paper and has even been investigated for use as an anti-cancer agent.
Dr Heutz made a scientific breakthrough when she experimented with clusters of MPc. She found that she could make the metal centres of MPc have tiny magnetic interactions with one another. Like placing two compasses together and controlling which way the arrows point, she found that she could control how the metal centres of MPc spin in relation to one another.
The secret to controlling this spin lies in the way Dr Heutz experimented with MPc. She grew stacks of MPc in crystal structures on plastic surfaces and then experimented with the preparation conditions. She grew them at room temperature; applied heat; chemically altered the plastic surfaces that the crystals grew on; and so changed the way the crystals grew. All these different elements altered the way the metal centres interacted with each other.
Image 2: The structure of stacks of MPc molecules
After three years of experimentation, the team can now control a set of microscopic interactions between the molecules.
Current information processing uses a switching process of zeros and ones to process and store ‘bits’ of information. Dr Heutz believes she could improve on this process to increase memory. So far the team can switch the interactions from ‘on/off’ and change the state of the interaction from ‘on’ to a different type of ‘on’. They are still experimenting with ways to turn the interaction ‘off/on’. When they find this switch Dr Heutz believes she will have a superior set of molecular signals for information processing and storage.
“Electronic devices already use magnetism as a system for processing and storing information. These experiments prove that we will be able to replace the current electro-magnetic process with a magnetic interaction between molecules of MPc,” said Dr Heutz.
Dr Heutz says it could take several more years to apply this technology practically. When the refinements are complete she believes exploiting MPc molecules will have enormous benefits in the development of ‘spintronics’ - a process which relies on the spin of atoms or molecules to store trillions of bits of information per square inch.
She also believes these molecular interactions have the potential to process ‘qubits’ of information in quantum computing. According to current theories, quantum computing is expected to harness the properties of quantum mechanics to perform tasks that classical computers cannot do in a reasonable time.
“We are still a long way off from applying this technology to the home PC. However, in five years time our experiments will demonstrate that we will have the power to unleash the vast potential of information processing at the molecular level,” she said.
Image 3: 60 nm thick MPc film (in blue-green) grown on a flexible substrate (kapton)
This research was published in Advanced Materials and was carried out by the London Centre for Nanotechnology - a joint enterprise between Imperial College London and University College London. It was funded by the Royal Society (Dorothy Hodgkin Fellowship and Wolfson Research Merit Award); Research Councils UK and the Engineering and Physical Sciences Research Council (EPSRC).
Note to editors:
 “Molecular Thin Films: A New Type of Magnetic Switch”, Advanced Materials, 19 (2007) 3618. [download PDF file]
S. Heutz 1 2, C. Mitra 2, W. Wu 2, A. J. Fisher 2, A. Kerridge 2 4,, M. Stoneham 2, A. H. Harker 2, J. Gardener 2, H.-H. Tseng 3, T. S. Jones 3 6, C. Renner 2 5, G. Aeppli 2
- Department of Materials and London Centre for Nanotechnology, Imperial College London
- Department of Physics and Astronomy and London Centre for Nanotechnology, University College London
- Department of Chemistry and London Centre for Nanotechnology, Imperial College London
- Department of Chemistry, University College London
- University of Geneva, Geneva, Switzerland
- Department of Chemistry, University of Warwick, Coventry
 “Magnetic Blue”, J. van den Brink and A. F. Morpurgo, Nature, 450 (2007) 177. [view online article]
2. About the London Centre for Nanotechnology
The London Centre for Nanotechnology is a joint enterprise between University College London and Imperial College London. In bringing together world-class infrastructure and leading nanotechnology research activities, the Centre aims to attain the critical mass to compete with the best facilities abroad. Furthermore by acting as a bridge between the biomedical, physical, chemical and engineering sciences the Centre will cross the 'chip-to-cell interface' - an essential step if the UK is to remain internationally competitive in biotechnology. Website: www.london-nano.com
3. About University College London
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. In the government's most recent Research Assessment Exercise, 59 UCL departments achieved top ratings of 5* and 5, indicating research quality of international excellence.
UCL is in the top ten world universities in the 2007 THES-QS World University Rankings, and the fourth-ranked UK university in the 2007 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Marie Stopes, Jonathan Dimbleby, Lord Woolf, Alexander Graham Bell, and members of the band Coldplay. Website: www.ucl.ac.uk
4. About Imperial College London
Rated as the world's fifth best university in the 2007 Times Higher Education Supplement University Rankings, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts over 12,000 students and 6,000 staff of the highest international quality.
Innovative research at the College explores the interface between science, medicine, engineering and management and delivers practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.
With 66 Fellows of the Royal Society among our current academic staff and distinguished past members of the College including 14 Nobel Laureates and two Fields Medallists, Imperial's contribution to society has been immense. Inventions and innovations include the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of our research for the benefit of all continues today with current focuses including interdisciplinary collaborations to tackle climate change and mathematical modelling to predict and control the spread of infectious diseases.
The College's 100 years of living science will be celebrated throughout 2007 with a range of events to mark the Centenary of the signing of Imperial's founding charter on 8 July 1907. Website: www.imperial.ac.uk