Magnet Cooling

A study published in the Physical Review Letters states that researchers from the Massachusetts Institute of Technology have formulated a new theory which states that magnets could be used as wireless cooling agents to cool laptops and refrigerators in the near future. The theory describes the motion of magnons – quasi particles in magnets that are collective rotations of magnetic moments which are also known as ‘spins’.

Magnons are known to conduct heat and when exposed to a magnetic field gradient, they are driven from one end of the magnet to another. During this movement they carry heat with them subsequently producing a cooling effect. The theory is formulated by Bolin Liao, Jiawei Zhou and Department of Mechanical Engineering head Gang Chen. They have termed this theory as ‘magnon cooling effect’ which is similar to ‘thermoelectric cooling effect’. Liao said that wireless cooling could be enabled by applying a magnetic field to a magnet one or two metres away to cool the laptop, In theory, a magnetically driven refrigerator would require no moving parts, unlike conventional iceboxes that pump fluid through a set of pipes to keep things cool.

To study the effect of magnon cooling, scientists used the properties of a magnetic insulator. It was found that at low temperatures the magnetic force was stronger while at high temperature the magnetic force was weaker. In both the cases, the material was able to generate a cooling effect.