Magnetocaloric Materials for Cryogenic Liquification

The liquification of light gasses (i.e., H2 and He) remains challenging today, as it requires expensive, large, and energetically costly equipment to produce liquid cryogens.  Materials exhibiting a large 'magnetocaloric' effect can be used to remove heat from a system when connected adiabatically.  When the maximum of this effect (which is typically temperature dependent) coincides with the boiling temperature of one of these cryogens, the material can be used to reliquify the gas when appropriately adiabatically connected to the gas and placed in an oscillatory magnetic field.   This disclosure describes materials that have a maximum magnetocaloric cooling effect at the temperature required for helium reliquification.

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