纳米囊
磁制冷
材料科学
纳米技术
化学工程
纳米颗粒
物理
磁化
工程类
磁场
量子力学
作者
X G Liu,Bing Li,Dongling Geng,Chunxiang Shi,Fang Yang,D. J. Kang,Z D Zhang
标识
DOI:10.1088/0022-3727/42/4/045008
摘要
HoAl2/Al2O3 nanocapsules with a core of HoAl2 and a shell of amorphous Al2O3 have been synthesized. The formation of the rare-earth compound nanocapsules can be ascribed to the different melting points and the optimal proportions of Ho and Al atoms during the arc-discharging process. Furthermore, the formation of the Al2O3 shell protects the rare-earth atoms from serious oxidation. The HoAl2/Al2O3 nanocapsules display superparamagnetic properties between the blocking temperature of 6 K and the Curie temperature of 26 K. The absolute value of the magnetic-entropy change in the HoAl2/Al2O3 nanocapsules rapidly increases with the decrease in temperature and reaches 14.7 J kg−1 K−1 at 3 K for a magnetic-field change from 0 to 70 kOe. As a result, this new type of nanocapsule may be applied, in the temperature range studied, in cryogenic magnetic-refrigerator devices.
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