Large cryogenic magnetocaloric effect in the blocking state of GdAl2/Al2O3 nanocapsules

doi:10.1103/PhysRevB.76.144404

IMR OpenIR

	Large cryogenic magnetocaloric effect in the blocking state of GdAl2/Al2O3 nanocapsules
	Ma, S.; Li, W. F.; Li, D.; Xiong, D. K.; Sun, N. K.; Geng, D. Y.; Liu, W.; Zhang, Z. D.
通讯作者	Ma, S.()
	2007-10-01
发表期刊	PHYSICAL REVIEW B
ISSN	1098-0121
卷号	76 期号:14 页码:9
摘要	The nanocapsules with crystalline cores of GdAl2 compound and shells of amorphous Al2O3 were prepared by evaporating GdxAl100-x (x=50, 60, 70, 80, and 90) alloys using a modified arc-discharge technique. The morphologies, average sizes, lattice constants, and surface characteristics of GdAl2/Al2O3 nanocapsules were studied in detail by means of x-ray diffraction, energy dispersive spectroscopy, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The formation mechanism of the nanocapsules was analyzed in detail. The differences in Curie temperatures and anisotropy constants of these nanocapsules were discussed with respect to their different structural characteristics. From 180 to 5 K, the magnetic entropy change of the GdAl2/Al2O3 nanocapsules continuously increases with decreasing temperature T and rapidly enhances when the temperature tends to 5 K. The largest entropy change -Delta S at 7.5 K can respectively reach 18.02, 18.71, and 31.01 J kg(-1) K-1 by varying the magnetic field from 7 to 1 T for the nanocapsules synthesized by arc-discharging Gd70Al30, Gd80Al20, and Gd90Al10 alloys. The appearance of a large entropy change at low temperatures was ascribed to a lower anisotropy energy barrier and a high magnetic-moment density of the nanocapsules. The linear relation between the magnetic entropy change and the reciprocal of the temperature (1/T) was discussed in terms of superparamagnetism and magnetocaloric theory.
DOI	10.1103/PhysRevB.76.144404
收录类别	SCI
语种	英语
WOS研究方向	Physics
WOS类目	Physics, Condensed Matter
WOS记录号	WOS:000250620300054
出版者	AMER PHYSICAL SOC
引用统计	被引频次：31[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/91792
专题	中国科学院金属研究所
通讯作者	Ma, S.
作者单位	Chinese Acad Sci, Int Ctr Mat Phys, Shenyang Natl Lab Mat Sci, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Ma, S.,Li, W. F.,Li, D.,et al. Large cryogenic magnetocaloric effect in the blocking state of GdAl2/Al2O3 nanocapsules[J]. PHYSICAL REVIEW B,2007,76(14):9.
APA	Ma, S..,Li, W. F..,Li, D..,Xiong, D. K..,Sun, N. K..,...&Zhang, Z. D..(2007).Large cryogenic magnetocaloric effect in the blocking state of GdAl2/Al2O3 nanocapsules.PHYSICAL REVIEW B,76(14),9.
MLA	Ma, S.,et al."Large cryogenic magnetocaloric effect in the blocking state of GdAl2/Al2O3 nanocapsules".PHYSICAL REVIEW B 76.14(2007):9.