University of Leeds Develops Permanent Magnet without Rare Earth

The University of Leeds has made breakthroughs in seeking new, sustainable permanent magnet with no rare earth, according to foreign media reports. Most permanent magnets are made from rare earth alloys, but mining and processing such materials produce toxic by-products, leading to ecological challenges associated with rare-earth mines and refineries. Meantime, demand for the permanent magnet is increasing as they are a common component in renewable energy, consumer electronics, and electric-powered vehicles.

A team of scientists at the University of Leeds in the UK has made a breakthrough in a new advanced material, and this material may eventually be able to forego permanent magnet based on rare earth. The researchers developed a hybrid film made of a thin layer of cobalt, which is naturally magnetic and covered with molecules of Buckminsterfullerene, a form of carbon.

The presence of carbon dramatically boosted the magnetic energy product of cobalt, which can increase the magnetic energy product 5 times at low temperatures. The magnetic energy product is an indicator to measure the strength of the magnet.

The research team observed the increase in magnet strength at minus 195 degrees Celsius, hoping to manipulate the carbon molecules through chemical methods to obtain the same effect at room temperature.

Dr. Tim Moorsom, co-principal investigator of the School of Physics and Astronomy at the University of Leeds said: "This is the first indication I have seen that a rare-earth-free magnet could compare to something like samarium cobalt, a rare-earth-based permanent magnet. While we have only seen this effect at low temperatures thus far, I am hopeful that a hybrid magnetic material similar to this will one day replace rare earth permanent magnets, helping to mitigate the environmental damage they cause."

Although carbon is not magnetic, the bond of carbon molecules and the cobalt surface causes a magnetic pinning effect, preventing the magnetism in the cobalt from changing direction, even in strong opposing fields. This surface interaction is the key to the unusually high magnetic energy of the hybrid material.

Although it may take a long time to apply such a hybrid permanent magnet without rare earth to wind turbines or electric vehicles, there are other applications, which are closer at hand. Co-principal investigator Dr. Oscar Cespedes at University of Leeds said: "Although room temperature applications in bulk permanent magnetism may be a long way off, the use of molecular coupling to tune the magnetic properties of thin films, e.g. for magnetic memories, is a tantalizing prospect that is within easy reach."

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