Structural and Magnetic Properties of CoPt@Au Core-shell Nanoparticles Prepared under Ambient Pressure

T. H. Meen ； H. M. Liu ； C. J. Huang ； T. H. Fang ； L. W. Ji ； W. R. Chen ； W. Water ； J. K. Tsai

《Journal of Science and Innovation》 1卷2期 (2011/04) Pp. 1-6

https://doi.org/10.6654/JSI.201104_1(2).0001

並列摘要

In this study, cobalt platinum alloy-core/gold-shell (CoPt@Au) nanoparticles are prepared by reverse micelle method under ambient pressure, and investigated by X-ray diffraction, transmission electron microscopy (TEM), ultraviolet-visible absorption spectra, and superconducting quantum interference device (SQUID) analyses. Cobalt platinum alloy (CoPt) nanoparticles are synthesized via chemical assembly, and achieved by reducing 0.1M aqueous metal salts confined in the polar portions of inverse micelles of cetyltrimethylammonium bromide (CTAB) with borohydride. Gold-coated nanocomposites are prevented CoPt oxidation and allowed the samples to be manipulated without additional precautions to prevent oxidation. X-ray diffraction shows that the pattern of CoPt is hidden under the pattern of gold. TEM image reveals that the core-shell structure is obviously observed and the average size of CoPt@Au nanoparticles is about 6~7nm. The absorption band of CoPt@Au nanoparticles shifts to a longer wavelength and broadens relative to that of the pure gold. The results of magnetization for CoPt@Au nanoparticles reveal that they are super-paramagnetic, and the blocking temperatures is 75K. In addition, there is an weak ferromagnetism observed in the results of magnetization for CoPt@Au nanoparticles under-1000 Oe~1000 Oe at 5K, and the coercive fields is 20 Oe.

並列關鍵字

CoPt@Au ； Core-shell ； Nanoparticles ； Reverse Micelle Method