Recent progresses of the rare earth based intermetallics and alloys for hydrogen liquefaction.

Magnetic refrigeration (MR), utilizing the magnetocaloric effect (MCE) in magnetic solids, was considered as a high efficiency cooling technology which can be available in a wide temperature range from cryogenic to room temperature. However, large-scale MR applications are still in their early stages due to the lack of suitable candidate materials with prominent magnetocaloric performance. This article briefly reviews the research development of rare earth-based magnetocaloric materials that with potential applications for hydrogen liquefaction over the past five years. The magnetic and magnetocaloric properties as well as the origin of MCE in these updated magnetocaloric materials are summarized, which are expected to enhance understanding and further explore the magnetocaloric materials in hydrogen liquefaction temperature regimes. Structural and compositional modifications, including elemental substitution and composite design, can tune phase transition temperatures and enhanced refrigerant capacity, however the underlying reasons still need to be further explored.