Magnetic refrigeration

Magnetic refrigeration is a cooling technology based on the magnetocaloric effect. This technique can be used to attain extremely low temperatures (well below 1 kelvin), as well as the ranges used in common refrigerators, depending on the design of the system. The fundamental principle was suggested by Debye (1926) and Giauque (1927), and the first working magnetic refrigerators were constructed by several groups beginning in 1933. Magnetic refrigeration was the first method developed for cooling below about 0.3 kelvin (a temperature attainable by ³He/⁴He dilution refrigeration).
See more at Wikipedia.org...