Levitation experiments with radical high field superconducting magnet helps scientists bend the rules of gravity
A new type of high field superconducting magnet from Oxford Instruments has enabled physicists at the University of Nottingham to balance the force of gravity and levitate heavy and dense materials such as lead, gold and diamonds.
The patented minimum condensed volume (MCV) Cryofree superconducting magnet, developed and manufactured by Oxford Instruments in collaboration with the University of Nottingham, is the first of its kind in the world.
Unlike conventional superconducting magnets, the MCV magnet never needs to be refilled with liquid helium and yet can generate a field over 300,000 times stronger than the Earth's magnetic field.
The magnet is also designed with a much shorter bore than standard versions that is maintained at room temperature.
"This makes the magnet very easy to use and ideal to study the effects of simulated zero-gravity conditions on growing seedlings, for example - research which has relevance to future manned space exploration," said Laurence Eaves, Nottingham.
The Nottingham team has published its findings in the latest issue of Nature.
The experiment is based on the magneto-Archimedes effect, using cold (100K) oxygen gas in the magnetic field to levitate objects, such as diamonds, that are dense enough to sink in water.
Magnetised liquid oxygen provides even greater buoyancy, up to 340 times that of water, enabling even heavy metals such as gold and platinum to be levitated. Professor Eaves explained, "We are currently exploring the potential applications of this technology with our colleagues at the university.
It may prove to be valuable in the separation of precious metals and minerals from non-precious substances, which could have implications in mining.
Simulating zero-gravity in the lab on Earth to study how seeds grow and germinate under these conditions is also much less costly than performing these experiments on space missions." As the MCV Cryofree magnet never needs to be refilled with liquid helium, scientists could theoretically levitate objects indefinitely in order to research the long-term effects of simulated zero gravity conditions.
The magnet technology, however, may have much wider applications.
Jim Hutchins, sales director at Oxford Instruments, commented, "Helium is a limited natural resource and by never needing refills, the compact MCV superconducting magnets are helping to preserve the world's valuable and dwindling supplies. Additionally, the magnet is easier to use, as it requires less experience with cryogens.
MCV technology has the potential to be used for a wide range of magnet designs, supporting applications in materials studies and biochemical analysis." Conventional superconducting magnets used for this kind of research, work by using liquid helium to cool the superconducting magnetic coil so that the current flows without resistance.
The helium usually boils off and needs to be re-filled.
In addition to its minimal requirements for liquid helium, through innovative design the MCV has a very small footprint and, operating at 4.2K with a room temperature bore, can generate highly stable magnetic fields up to 16 Tesla.
The MCV holds the world record for strength and uniformity of magnetic field generated by a Cryofree magnet.
