Magnets May Be Used To Cool Laptops & Refrigerators In The Future

Researchers from Massachusetts Institute of Technology have formulated a new theory that proves that magnets are capable of acting as wireless cooling agents and may be used in the future to cool laptops and refrigerators.

The theory describes the motion of magnons. Magnons are quasi-particles in magnets that are collective rotations of magnetic moments, also known as 'spins'. These magnons are also known to conduct heat. Scientists revealed that when these magnons come in contact with a magnetic field gradient, they tend to move from one end of a magnet to another, while carrying heat with them and subsequently producing a cooling effect.

Bolin Liao, a graduate student in MIT's Department of Mechanical Engineering, said that heat can be pumped from one side to another, therefore allowing one to use the magnet as a refrigerator. This opens up the doors for the possibility of wireless cooling, where a magnetic field is applied to a magnet a few meters away in order to cool a laptop or a refrigerator. Unlike conventional refrigerators that keep cool by pumping fluid through a set of pipes, a magnetically driven refrigerator would require no moving parts whatsoever.

Liao and his colleagues devised two new equations to describe magnon transport. Using these equations, the scientists predicted a new magnon cooling effect, which was similar in nature to the thermoelectric cooling effect. In the thermoelectric cooling effect, magnons may carry heat from one end of a magnet to the other when they were exposed to a magnetic field gradient.

The properties of a common magnetic insulator were used to model the manner in which this magnon cooling effect would work in existing magnetic materials. While this effect was found to be small, a cooling effect was generated by the material in response to a moderate magnetic field gradient. At cryogenic temperatures, this effect was found to be more significant.