Large cryogenic magnetocaloric effect in the blocking state of GdAl(2)/Al(2)O(3) nanocapsules
文献类型：期刊论文
| 作者 | S. Ma ; W. F. Li ; D. Li ; D. K. Xiong ; N. K. Sun ; D. Y. Geng ; W. Liu ; Z. D. Zhang |
| 刊名 | Physical Review B
 |
| 出版日期 | 2007 |
| 卷号 | 76期号:14 |
| 关键词 | magnetic entropy change fe-co(c) nanocapsules arc-discharge iron-oxide gdal2 nanoparticles particles nanocomposites refrigeration polarization |
| ISSN号 | 1098-0121 |
| 中文摘要 | The nanocapsules with crystalline cores of GdAl(2) compound and shells of amorphous Al(2)O(3) were prepared by evaporating Gd(x)Al(100-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 GdAl(2)/Al(2)O(3) 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 GdAl(2)/Al(2)O(3) 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 Gd(70)Al(30), Gd(80)Al(20), and Gd(90)Al(10) 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. |
| 原文出处 | |
| 公开日期 | 2012-04-13 |
| 源URL | [http://ir.imr.ac.cn/handle/321006/33752]  |
| 专题 | 金属研究所_中国科学院金属研究所 |
| 推荐引用方式 GB/T 7714 | S. Ma,W. F. Li,D. Li,et al. Large cryogenic magnetocaloric effect in the blocking state of GdAl(2)/Al(2)O(3) nanocapsules[J]. Physical Review B,2007,76(14). |
| APA | S. Ma.,W. F. Li.,D. Li.,D. K. Xiong.,N. K. Sun.,...&Z. D. Zhang.(2007).Large cryogenic magnetocaloric effect in the blocking state of GdAl(2)/Al(2)O(3) nanocapsules.Physical Review B,76(14). |
| MLA | S. Ma,et al."Large cryogenic magnetocaloric effect in the blocking state of GdAl(2)/Al(2)O(3) nanocapsules".Physical Review B 76.14(2007). |
入库方式： OAI收割
来源：金属研究所
浏览0
下载0
收藏0
其他版本
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。