Crystal electric field level scheme leading to giant magnetocaloric effect for hydrogen liquefaction
Crystal electric field level scheme leading to giant magnetocaloric effect for hydrogen liquefaction
复制标题
导致氢液化巨磁热效应的晶体电场级方案
DOI：
10.1038/s43246-023-00340-z
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发表时间：
2023
影响因子：
7.8
通讯作者：
and Hideaki Kitazawa
中科院分区：
文献类型：
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作者：
Noriki Terada;Hiroaki Mamiya;Hiraku Saito;Taro Nakajima;Takafumi D. Yamamoto;Kensei Terashima;Hiroyuki Takeya;Osamu Sakai;Shinichi Itoh;Yoshihiko Takano;Masashi Hase;and Hideaki Kitazawa
近年来，磁制冷在氢液化方面引起了广泛的关注。大多数用于磁制冷的材料含有重稀土离子，具有复杂的晶体电场能量分裂，其对磁熵变化的影响ΔSMhas尚未系统研究。特别是，对于一般重土情况，理论上限ΔSM∣是未知的。在这里，我们证明了晶体电场能级方案导致了一个大ΔSMfor一般重稀土的情况。利用非弹性中子散射实验，结合晶体场分裂和交换相互作用的平均场计算，给出了磁致冷材料hob2的具体例子。本研究中提出的ΔSMand晶体场参数之间的关系可用于开发具有大∣ΔSM∣的化合物和推进磁制冷材料的设计。
In recent years, magnetic refrigeration has attracted considerable attention for hydrogen liquefaction. Most materials used for magnetic refrigeration contain heavy rare earth ions with complex crystalline electric field energy splittings, whose effect on the magnetic entropy change ΔSMhas not been systematically studied. In particular, the theoretical upper limits of ∣ΔSM∣ for general heavy earth cases are unknown. Here, we show that the crystalline electric field level schemes result in a large ΔSMfor general heavy rare earth cases. We provide a specific example of the magnetic refrigeration material HoB2using inelastic neutron scattering experiments combined with mean-field calculations with crystal field splitting and exchange interactions. The relationship between ΔSMand crystal field parameters presented in this study can be useful for developing compounds with a large ∣ΔSM∣ and advancing the design of magnetic refrigeration materials.