Magnets are central to much modern technology and firms are racing to make them more efficient
At present, China massively dominates global permanent magnet production, with more than 90% market share.
Matthew Swallow says magnets have become much more powerful over the past 10 years.
Higher grade magnets mean motors that run more efficiently and cars that weigh slightly less overall.
One reason why China dominates global production of these magnets is financial incentives, says Ross Embleton, senior analyst for metals & mining - rare earths at Wood Mackenzie.
US firm Niron Magnetics says it has managed to make good quality magnets without rare earths.
Mr Rowntree says it should be possible to make significantly more powerful magnets, up to 2.4 teslas, with iron nitride.
Recycling magnets would also be much better for the environment compared with making new rare earth magnets from scratch.
The whole process is about 40% more efficient than traditional virgin magnet production.
Mr Swallow cites other emerging applications that sound quite sci-fi - including magnets mounted on satellites to scoop up space debris orbiting Earth.
Dr Kroh says he is looking forward to even more sophisticated magnets that will make other surgeries less invasive than before.