National MagLab creates a miniature magnet producing the largest magnetic field yet

National High Magnetic Fieldac
Diagram of 45 Tesla hybrid magnet (Credits - Wikimedia Commons)

A magnet which is half the size of a cardboard tissue roll has now the title of “world’s strongest magnetic field“. But the makers say that this is just the beginning. By packing such a strong magnetic field in a coil which can be carried in pockets, engineers from MagLab have shown ways to build electromagnets which are powerful, smaller in size and thus portable. The study has been published in the Nature journal.
MagLab scientist, Seungyong Hahn who is the head behind this project and also a professor at the FAMU-FSU College of Engineering remarked that they are opening a new door to a limitless future of possibilities. This technology has the ability to change high-field applications in a way never known before due to its compact nature.
Director of National MagLab, Greg Boebinger remarked that this new magnet is a David to the conventional Goliaths which are made by MagLab. He further added it has the capacity to bring a revolution in magnets the way silicon brought to the world of electronics. This feat is a tribute to the quality of faculty and the nature of research in the laboratory.
So the magnetic field generated by the miniature magnet is a massive 45.5 Tesla. A regular MRI magnet at the hospital produces nearly 2 to 3 Tesla. Before this, the strongest and continuous magnetic field was produced by MagLab’s own 35-ton magnet since 1999, amounting to 45 Tesla. This magnet known as 45-T is still the strongest working magnet in the world. It makes high edge research possible in the field of materials science.
The new mini magnet invented by Hahn weighs 390 grams and it briefly surpassed the magnetic field of the giant magnet by half a Tesla. So the question arises, how can a magnet so small surpass the magnetic field that huge. The answer lies in the design and use of conductors.

The superconductors used in 45.5 T are niobium-based alloys which have been used for quite some time. In addition to it, a newer compound named REBCO( rare earth barium copper oxide) was used here. Its current density is twice that of a section of the niobium superconductor. The REBCO product which was used here, paper-thin wires that are tape-shaped was manufactured by SuperPower Inc. 
This magnet also does not contain insulation, which is present in many modern day electromagnets. Without insulation, the current flows different paths and avoid quenches. Quenches occur due to damages in the conductor which cause the magnet to heat up and thus lose superconducting properties.
The main problem in REBCO is that it is a single filament conductor which cannot be manufactured perfectly. So it will have a variety of defects whose impact cannot be understood properly now. This is the challenge which scientists have to resolve next.


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