Magnetic refrigeration

Gadolinium alloy heats up inside the magnetic field and loses thermal energy to the environment, so it exits the field and becomes cooler than when it entered.

Magnetic refrigeration 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.[1][2][3][4]

A magnetocaloric material warms up when a magnetic field is applied. The warming is due to changes in the internal state of the material releasing heat. When the magnetic field is removed, the material returns to its original state, reabsorbing the heat, and returning to original temperature. To achieve refrigeration, the material is allowed to radiate away its heat while in the magnetized hot state. Removing the magnetism, the material then cools to below its original temperature.

The effect was first observed in 1881 by a German physicist Emil Warburg, followed by French physicist P. Weiss and Swiss physicist A. Piccard in 1917.[5] The fundamental principle was suggested by P. Debye (1926) and W. Giauque (1927).[6] 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 K (the lowest temperature attainable before magnetic refrigeration, by pumping on 3
He vapors).

  1. ^ França, E.L.T.; dos Santos, A.O.; Coelho, A.A. (2016). "Magnetocaloric effect of the ternary Dy, Ho and Er platinum gallides". Journal of Magnetism and Magnetic Materials. 401: 1088–1092. Bibcode:2016JMMM..401.1088F. doi:10.1016/j.jmmm.2015.10.138.
  2. ^ Brück, E. (2005). "Developments in magnetocaloric refrigeration". Journal of Physics D: Applied Physics. 38 (23): R381–R391. Bibcode:2005JPhD...38R.381B. doi:10.1088/0022-3727/38/23/R01. S2CID 122788079.
  3. ^ Khovaylo, V. V.; Rodionova, V. V.; Shevyrtalov, S. N.; Novosad, V. (2014). "Magnetocaloric effect in "reduced" dimensions: Thin films, ribbons, and microwires of Heusler alloys and related compounds". Physica Status Solidi B. 251 (10): 2104. Bibcode:2014PSSBR.251.2104K. doi:10.1002/pssb.201451217. S2CID 196706851.
  4. ^ Gschneidner, K. A.; Pecharsky, V. K. (2008). "Thirty years of near room temperature magnetic cooling: Where we are today and future prospects". International Journal of Refrigeration. 31 (6): 945. doi:10.1016/j.ijrefrig.2008.01.004.
  5. ^ Weiss, Pierre; Piccard, Auguste (1917). "Le phénomène magnétocalorique". J. Phys. (Paris). 5th Ser. (7): 103–109.
    Smith, Anders (2013). "Who discovered the magnetocaloric effect?". The European Physical Journal H. 38 (4): 507–517. Bibcode:2013EPJH...38..507S. doi:10.1140/epjh/e2013-40001-9. S2CID 18956148.
  6. ^ Zemansky, Mark W. (1981). Temperatures very low and very high. New York: Dover. p. 50. ISBN 0-486-24072-X.