Researchers in Cambridge have successfully trapped a magnetic field with a strength of 17.6 Tesla, beating the 17,2 Tesla of the previous record which stood strong for 11 years. They used a high temperature gadolinium barium copper oxide superconductor, which in comparison to a normal fridge magnet, has around 100 times the strength.
[Image Source: University of Cambridge]
The research shows off potential of high-temperature superconductors when it comes to applications in numerous fields. This includes flywheels for energy storage along with magnetic separators which could be used in the refinement of minerals and control of pollution. Oh and not to forget MagLev trains, levitating monorail trains which travel at high speeds.
Superconductors carry electrical currents that have little or no resistance at all when they are cooled down to a certain temperature. Typically, they have to be cooled close to around absolute zero before super conduction occurs; the high temperature superconductors conduct at above the boiling point of liquid nitrogen, which is -196 degree centigrade.
Typically superconductors are used for medical applications, this includes equipment such as MRI scanners. In the future it could be possible for superconductors to be used as a way of increasing energy efficiency along with protecting the national grid. This is due to the fact that they carry electrical current at high efficiency.
The current of the superconductor is able to generate a magnetic field, with the more field strength it possesses, the more current it is able to carry. The latest superconductors are able to manage a current that is around 100 times more than copper and as such, they have a lot more performance advantages than the permanent magnets or the conventional conductors.
Researchers were able to achieve the record thanks to using samples of GdBCO of 25 mm in diameter, high temperature superconductors by way of a large single grain and using a melt process method that is established. The previous record was set in 2003 at 17.2 Tesla by Professor Masato Murakami from the Shibaura Institute of Technology in Japan. The team used a specialised superconductor which had subtle differences to the structure and composition.
“The fact that this record has stood for so long shows just how demanding this field really is,” said Professor David Cardwell of Cambridge’s Department of Engineering, leader of the research, in collaboration with Boeing and the National High Field Magnet Laboratory at the Florida State University. “There are real potential gains to be had with even small increases in field.”
The team has to use materials which are known as cuprates, in order to contain a large field that was so large, these are thin copper and oxygen sheets. These had been the earliest high temperature superconductors to have been discovered. They also have the potential to be able to be used in more widely when it comes to medical and scientific applications.
They do have superb potential for practical applications; however the downside is that they are brittle. They can be compared to dry pasta, which snaps when bent. Researchers needed to modify the GdBCO microstructure so as to increase the current it is carrying along with thermal performance, reinforcing it with a stainless steel ring and shrink wrapping the single grains. Dr John Durrell said that this had been a very important step in getting the results.
“This work could herald the arrival of superconductors in real-world applications,” said Professor Cardwell, Head of the Department of Engineering. “In order to see bulk superconductors applied for everyday use, we need large grains of superconducting material with the required properties that can be manufactured by relatively standard processes.”
It was said that many niche applications are at the moment being developed by the team and widespread commercial application of the superconductors may be seen in the next five years.
“This record could not have been achieved without the support of our academic and industrial colleagues and partners,” said Cardwell. “It was a real team effort, and one which we hope will bring these materials a significant step closer to practical applications.”
“Boeing continues to see practical applications for this superconducting material research and we are excited about the possibilities being enabled by the recent advances achieved by the Cambridge team,” said Patrick Stokes, leader of the Boeing-funded research portfolio with Cambridge University.