Xu Qiao-Fei, Chen Man-Ting, Ye Ming-Yu, Liu Bo-Liang, Zhuang Gui-Lin, Long La-Sheng, Zheng Lan-Sun
Collaborative Innovation Center of Chemistry for Energy Materials, State Key Laboratory of Physical Chemistry of Solid Surface and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Key Laboratory of Functional Molecular Solids, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui 241002, China.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32394-32401. doi: 10.1021/acsami.4c04538. Epub 2024 Jun 14.
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 (-Δ) and magnetic ordering temperature (). Although, based on the factors affecting the -Δ of magnetic refrigerants, one has been able to judge if a magnetic refrigerant has a large -Δ, how to accurately predict their remains a huge challenge due to the fact that the of magnetic refrigerants is related to not only magnetic exchange but also single-ion anisotropy and magnetic dipole interaction. Here, we, taking GdCOF (), Gd(HCOO)F, Gd(SO)·8HO, GdF, Gd(HCOO) and Gd(OH) as examples, demonstrate that the 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 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.
已知绝热去磁制冷是唯一一种能够在无重力条件下实现超低温（≪1 K）的低温制冷技术。评估磁性制冷剂性能的关键指标是它们的磁熵变（-Δ）和磁有序温度（）。尽管基于影响磁性制冷剂-Δ的因素，人们已经能够判断一种磁性制冷剂是否具有较大的-Δ，但由于磁性制冷剂的 不仅与磁交换有关，还与单离子各向异性和磁偶极相互作用有关，因此如何准确预测它们的 仍然是一个巨大的挑战。在此，我们以GdCOF（）、Gd（HCOO）F、Gd（SO）·8HO、GdF、Gd（HCOO）和Gd（OH）为例，证明通过将平均场近似与量子蒙特卡罗模拟相结合，可以准确预测具有非常弱的磁相互作用和小各向异性的磁性制冷剂的 ，为预测超低温磁性制冷剂的 提供了一种有效方法。因此，本工作为未来超低温磁性制冷剂的合理设计和制备奠定了坚实的基础。
