Super Conduction

A study published in the journal Superconductor Science and Technology states that University of Cambridge engineers have harnessed the equivalent of three tonnes of force inside a golf ball-sized sample of material to set a new world record in super conduction. The earlier record of 17.2 Tesla, set in 2003 by a team led by Professor Masato Murakami from the Shibaura Institute of Technology in Japan, used a highly specialised type of superconductor of a similar, but subtly different, composition and structure.

Cambridge researchers managed to trap a magnetic field with a strength of 17.6 Tesla exceeding the previous record by 0.4 Tesla. The team used gadolinium barium copper oxide (GdBaCuO) to trap the magnetic field that is around 100 times stronger than the field generated by a fridge magnet. It has applications in a range of fields including flywheels for energy storage, 'magnetic separators', which can be used in mineral refinement and pollution control, and in high-speed levitating monorail trains. Superconductors are currently used in MRI scanners and in future could be used to protect the national grid and increase energy efficiency due to the amount of electrical current they can carry without losing energy. Superconductors are materials that carry electrical current with little or no resistance when cooled below a certain temperature. The current carried by a superconductor also generates a magnetic field, and the more field strength that can be contained within the superconductor, the more current it can carry. State of the art, practical superconductors can carry currents that are typically 100 times powerful than copper.

Researchers made use of 25 mm diameter samples of GdBaCuO high temperature superconductor to trap three tonnes of force inside the material, which is usually as brittle as fine china. To contain the large field, scientists made use of cuprates, i.e. thin sheets of copper and oxygen separated by more complex types of atoms, which are the earliest high temperature superconductors to be discovered. In spite of the high conductivity, they are brittle as dried pasta, which causes them to explode when containing a strong magnetic field. In order to hold in, or trap the magnetic field, researchers modified both the microstructure of GdBaCuO by reinforcing it with a stainless steel ring to increase its current carrying capacity and thermal performance.