Enhanced Cryogenic Magnetocaloric Effect Induced by Small Size GdNi5 Nanoparticles
Enhanced Cryogenic Magnetocaloric Effect Induced by Small Size GdNi5 Nanoparticles
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DOI：
10.1016/j.jmst.2014.01.009
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发表时间：
2014-10-01
影响因子：
10.9
通讯作者：
Zhang, Zhidong
中科院分区：
文献类型：
--
作者：
Li, Jun;Ma, Song;Zhang, Zhidong
采用电弧放电法在不同氢分压下制备了GdNi 5纳米粒子和GdNi 5/Gd 2 O3纳米胶囊（GdNi 5核Gd 2 O3壳）。GdNi 5纳米颗粒呈不规则球形，粒径分布在10-50 nm之间，平均粒径为15 nm。相比之下，GdNi 5/Gd 2 O3纳米胶囊呈现球形形貌，显示出10-100 nm的平均直径为60 nm的尺寸分布。在50 kOe的磁场变化下，GdNi 5纳米粒子的最大磁熵变在5 K时为13.5 J/（kg K），而GdNi 5/Gd 2 O3纳米胶囊的最大磁熵变在31 K时仅为5.7 J/（kg K）。GdNi 5纳米颗粒的大磁熵变的原因是由于其小的颗粒尺寸引起的高原子磁矩和小的各向异性能垒。
GdNi5 nanoparticles and GdNi5/Gd2O3 nanocapsules (with GdNi5 core and Gd2O3 shell) were prepared by arc-discharge technique under different hydrogen partial pressure. The GdNi5 nanoparticles show irregular spherical shape and have a size distribution of 10-50 nm with an average diameter of 15 nm. In comparison, the GdNi5/Gd2O3 nanocapsules present spherical morphology and show a size distribution of 10-100 nm with an average diameter of 60 nm. Under a magnetic field change of 50 kOe, the maximum magnetic entropy change of GdNi5 nanoparticles is 13.5 J/(kg K) at 5 K, while the corresponding value of the GdNi5/Gd2O3 nanocapsuels is only 5.7 J/(kg K) at 31 K. The origin of the large magnetic entropy change of GdNi5 nanoparticles is ascribed to its high atomic moments and small anisotropy energy barrier induced by its small particle size.