Shao Yanyan, Cheng Siyu, Zhang Mingxiao, Miao Xuefei, Zhang Yujing, Chen Haifeng, Han Zhida, Xu Feng
School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
CISRI & NIMTE Joint Innovation Center for Rare Earth Permanent Magnets, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
ACS Appl Mater Interfaces. 2025 Jan 8;17(1):1654-1661. doi: 10.1021/acsami.4c18839. Epub 2024 Dec 28.
Magnetocaloric high-entropy alloys (HEAs) have recently garnered significant interest owing to their potential applications in magnetic refrigeration, offering a wide working temperature range and large refrigerant capacity. In this study, we thoroughly investigated the structural, magnetic, and magnetocaloric properties of equiatomic GdDyHoErTm HEAs. The as-cast alloy exhibits a single hexagonal phase, a randomly distributed grain orientation, and complex magnetism. In particular, multiple magnetic phase transitions occur over a wide temperature range in this rare-earth HEA, which is attributed to the diverse magnetic properties of the constituent rare-earth elements. Accordingly, a table-like magnetocaloric effect (the maximum magnetic entropy change of 7.5 J/kg K at 5 T) is achieved in the temperature range of 27-175 K, leading to a giant refrigerant capacity of 923 J/kg and relative cooling power of 1110 J/kg. Our findings in the rare-earth HEAs with multiple magnetic phase transitions open up a pathway to further develop high-performance magnetocaloric materials in the field of cryogenic magnetic refrigeration.
磁热高熵合金（HEAs）因其在磁制冷中的潜在应用最近引起了极大关注，它具有宽工作温度范围和大制冷量。在本研究中，我们深入研究了等原子GdDyHoErTm高熵合金的结构、磁性和磁热性能。铸态合金呈现单一六方相、随机分布的晶粒取向和复杂磁性。特别是，在这种稀土高熵合金中，在很宽的温度范围内发生多次磁相变，这归因于组成稀土元素的不同磁性。因此，在27 - 175 K温度范围内实现了类似表格的磁热效应（在5 T时最大磁熵变为7.5 J/kg K），导致巨大的制冷量923 J/kg和相对制冷功率1110 J/kg。我们在具有多次磁相变的稀土高熵合金中的发现为低温磁制冷领域进一步开发高性能磁热材料开辟了一条途径。
