New Class of Swelling Magnets May Change the Future of Energy

A new class of magnets that expand their volume when placed in a magnetic field and generate negligible amounts of wasteful heat during energy harvesting could be the future of new actuators. The magnets have the potential to not only displace existing technologies, but also create new applications.

In the 1840s, a physicist discovered that iron-based magnet materials changed their shape but not their volume when placed in a magnetic field. This phenomenon was dubbed "Joule Magnetostriction." Since this discovery, all magnets have been characterized on this basis.

"Our findings fundamentally change the way we think about a certain type of magnetism that has been in place since 1841, said Harsh Deep Chopra, one of the researchers, in a news release.

In this case, the scientists discovered a new class of magnets, called "Non-Joulian Magnets," which show a large volume change in magnetic fields. These non-Joulian magnets also possess the remarkable ability to harvest or convert energy with minimal heat loss.

The new magnets were discovered when scientists treated certain iron-based alloys by heating them in a furnace at about 760 degrees Celsius for 30 minutes. Then, the researchers rapidly cooled them to room temperature. This caused the materials to exhibit non-Joulian behavior.

Since non-Jourlian magnets spontaneously expand in all direction, this means that compact omnidirectional actuators can now be created. In fact, the magnets can be used to create a new generation of sensors and actuators with very small heat signatures. They could be used for aerospace, automobile, biomedical, space and robotics applications.

The findings could be huge for future technologies and applications. The fact that these magnets exist means that new possibilities are opened for research and development.

The findings are published in the journal Nature.

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