Review of the strategies for regulating working temperatures of rare-earth-based low temperature magnetic cooling materials

Magnetic refrigeration technology based on the magnetocaloric effect (MCE) shows great potential for application in low-temperature fields such as nitrogen, helium, and hydrogen liquefaction. Rare-earth-based compounds usually display outstanding magnetocaloric performance due to the vacant 4f shell and larger magnetic moments, so they have attracted much attention. The working temperature is one of the core parameters of low-temperature magnetic refrigeration materials, which needs to match specific application scenarios (∼ 4.2 K for liquid helium, ∼ 20 K for liquid hydrogen, ∼ 77 K for liquid nitrogen). This paper reviews the strategies for regulating the working temperatures of rare-earth-based low-temperature magnetic refrigeration materials and concentrates on low-spin rare-earth substitution, zero-spin rare-earth substitution, amorphous engineering, and non-rare-earth atom substitution methods. It provides references for designing low-temperature magnetic refrigeration materials with desired working temperatures.