It is a cooling technology based on the magnetocaloric effect. This technique can be used to attain extremely low temperatures, as well as the ranges used in common refrigerators. Compared to traditional gas-compression refrigeration, magnetic refrigeration is safer, quieter, more compact, has a higher cooling efficiency, and is more environmentally friendly because it does not use harmful, ozone-depleting coolant gases.
The effect was first observed by French physicist P. Weiss and Swiss physicist A. Piccard in 1917. The fundamental principle was suggested by P. Debye (1926) and W. Giauque (1927).
The first working magnetic refrigerators were constructed by several groups beginning in 1933. Magnetic refrigeration was the first method developed for cooling below about 0.3K (a temperature attainable by 3He refrigeration. (That is pumping on the 3He vapours).