1. Accurate Prediction of the Magnetic Ordering Temperature of Ultralow-Temperature Magnetic Refrigerants.
- Author
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Xu QF, Chen MT, Ye MY, Liu BL, Zhuang GL, Long LS, and Zheng LS
- Abstract
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 S
m ) and magnetic ordering temperature ( T0 ). Although, based on the factors affecting the -Δ Sm of magnetic refrigerants, one has been able to judge if a magnetic refrigerant has a large -Δ Sm , how to accurately predict their T0 remains a huge challenge due to the fact that the T0 of magnetic refrigerants is related to not only magnetic exchange but also single-ion anisotropy and magnetic dipole interaction. Here, we, taking GdCO3 F ( 1 ), Gd(HCOO)F2 , Gd2 (SO4 )3 ·8H2 O, GdF3 , Gd(HCOO)3 and Gd(OH)3 as examples, demonstrate that the T0 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 T0 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.- Published
- 2024
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