Oct 18 2010
Scientists have captured the first direct images of magnetic monopoles which were theoretically conceived by the British-Swiss physicist Dirac in the early 1930s who showed that their existence is consistent with the ultimate theory of matter – quantum theory.
According to the findings published on 17 Oct 2010 in the leading scientific journal Nature Physics, the scientists were able to directly image the monopoles by using the highly intense x-ray radiation from the Swiss Light Source at the Paul Scherrer Institute.
“A magnetic monopole is a ‘hypothetical’ particle that is a magnet with only one single magnetic pole,” says Prof Hans-Benjamin Braun from the UCD School of Physics, University College Dublin one of the scientists involved in the discovery.
“Some of the most important theories explaining how quantum matter behaves in the universe are based on their existence, but they have eluded direct imaging since they were first theoretically conceived in the 1930s.”
“We have for the first time directly imaged monopoles inside an artificially created magnetic nano-metamaterial consisting of tiny magnets with a size of a couple of hundred nanometers,” says Professor Braun.
As Dirac predicted, the monopoles observed by the researchers come with `strings attached’ – the so called `Dirac strings’ which feed magnetic flux into the magnetic monopole in very much the same way a garden hose feeds water into a sprinkler.
The scientific team were able to capture the first direct images of the elusive monopoles together with their attached Dirac strings at room temperature.
“We also directly observed how north- and south pole separate from each other in an external field, creating the Dirac string in their wake,” says Dr Laura Heyderman from the Paul Scherrer Institute in Switzerland another of the scientists involved in the research. “In addition we have now demonstrated how to control the motion of these monopoles.”
When the researchers examined the way the monopoles moved, they realized that each time they increased the applied magnetic field they triggered an avalanche of magnetization reversal of adjacent islands, similar to a row of toppling dominoes. These types of avalanches are not simply restricted to magnetic systems, but apart from their snowy and icy counterparts, they also may manifest themselves in sand, in earthquakes, and in stockmarket crashes.
The research, funded by Science Foundation Ireland and the Swiss National Science Foundation, may ultimately assist scientists working to understand how monopoles might have interacted in the early universe.
But, they may also have far more immediate applications in data transfer and storage. So far, only electric charges have been used in information processing and the use of magnetic charges could provide significant advantage in power consumption and speed.
Current computer hard discs store data magnetically, and their next generation will most likely be built from tiny isolated magnets precisely of the type investigated in this research. Thus, with improved understanding of the behaviour of magnetic monopoles scientists would be able to develop hard discs with considerably higher density data storage and faster data transfer speeds.
Source: http://www.ucd.ie/