Brilliant cryogenic magnetic refrigerant with excellent magnetocaloric effect and refrigeration performances

There is an urgent demand for the development of new resource-saving and high-efficiency cryogenic refrigeration technologies against the historical backdrop of increasing scarcity of resources and energy. Magnetic refrigeration technology based on the magnetocaloric effect (MCE) of magnetic materials is a promising approach to address helium resource constraints and improve energy efficiency. Here, a brilliant cryogenic magnetic refrigerant with a large low-field MCE and excellent refrigeration performance is presented. Benefiting from the enhanced ferromagnetism and low saturation magnetic field, the peaks of magnetic entropy change, refrigeration capacity, and adiabatic temperature change of Eu(Ti,Nb,Zr)O₃ compounds reach 19.6 J·kg⁻¹·K⁻¹, 87.6 J·kg⁻¹, and 5.5 K, respectively, for a field change of 0−1 T. Magnetic refrigeration experiments on a Gifford‒McMahon (GM)/magnetic hybrid refrigerator further demonstrated that EuTi_0.8375Nb_0.0625Zr_0.1O₃ is an excellent magnetic refrigerant operating near the liquid helium temperature. An appropriate amount of this magnetic refrigerant can significantly improve the refrigeration performance of the hybrid refrigerator. The cooling power in hybrid refrigeration mode is improved by a maximum of 52% over that in pure GM/HoCu₂ mode at 4.2 K and 0.5 Hz. In addition, the cooling efficiency at 4.2 K is more than 40% greater than that of the pure GM/HoCu₂ refrigerator.