Accurate Prediction of the Magnetic Ordering Temperature of Ultralow-Temperature Magnetic Refrigerants

• Published in: ACS applied materials & interfaces 2024-06, Vol.16 (25), p.32394-32401
• Main Authors: Xu, Qiao-Fei, Chen, Man-Ting, Ye, Ming-Yu, Liu, Bo-Liang, Zhuang, Gui-Lin, Long, La-Sheng, Zheng, Lan-Sun
• Format: Article
• Language: English
• Subjects: anisotropy; entropy; Functional Inorganic Materials and Devices; magnetism; prediction; refrigeration; temperature
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.4c04538

Adiabatic demagnetization refrigeration is known to be the only cryogenic refrigeration technology that can achieve ultralow temperatures (≪1 K) at gravity-free conditions. The key indexes to evaluate the performance of magnetic refrigerants are their magnetic entropy changes (−ΔS m) and magnetic ordering temperature (T 0). Although, based on the factors affecting the −ΔS m of magnetic refrigerants, one has been able to judge if a magnetic refrigerant has a large −ΔS m, how to accurately predict their T 0 remains a huge challenge due to the fact that the T 0 of magnetic refrigerants is related to not only magnetic exchange but also single-ion anisotropy and magnetic dipole interaction. Here, we, taking GdCO3F (1), Gd­(HCOO)­F2, Gd2(SO4)3·8H2O, GdF3, Gd­(HCOO)3 and Gd­(OH)3 as examples, demonstrate that the T 0 of magnetic refrigerants with very weak magnetic interactions and small anisotropy can be accurately predicted by integrating mean-field approximation with quantum Monte Carlo simulations, providing an effective method for predicting the T 0 of ultralow-temperature magnetic refrigerants. Thus, the present work lays a solid foundation for the rational design and preparation of ultralow-temperature magnetic refrigerants in the future.