Prepared and Magnetic Properties of B₄C/C Coated Co Nanocapsules

Abstract:

B4C/C coated Co nanocapsules were prepared by arc-discharging a Co-B amorphous alloy. The structure, morphology and surface composition as well as magnetic properties were investigated by X-Ray diffraction, High Resolution Transmission Electron Microscopy and XPS photoelectron spectrum as well as Vibrating Sample Magnetometer, respectively. The results show the as-prepared nanoparticles form in a core¬¬¬-shell structure with the size of nanoparticles in range of 20-100nm, the thickness of the shell is about 3-10nm. The core is Co grains, while the shell is B4C/C compound. That B4C coated Co nanoparticles form in a core¬¬¬-shell structure ascribed to Co as catalysts accelerating reaction between B with C ionize in the arc-discharge course. This structure can prevent Co nanoparticles from oxidation and agglomeration. A saturation magnetization of Ms=75.6 Am2/kg and a coercive force of Hc=20.1 kA/m are achieved for as-prepared nanocapsules by VSM. For as–prepared nanocapsules, the saturation magnetization is reduced and coercive force of is enhanced while Comparing with Co block. The increase coercive force for as-prepared nanoparticles can be mainly ascribed to size of particles diminished and the domain-wall depinned in the multi-domain particles.

• Periodical: Materials Science Forum (Volume 694)
• Pages: 328-331
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.694.328
• Online since: July 2011
• Authors: Da Wei Yu, Jin Bing Zhang, Gui Mei Shi
• Keywords: Arc-Discharge, Co(B₄C/C), Core-Shell Structure, Magnetic Property

References

[1] C.P. Gibson, K.J. Putzer: Science Vol. 267 (1995), pp.1338-1340.

[2] D.Y. Geng, Z.D. Zhang, W.S. Zhang, etc:. Scripta Materialia Vol. 48(3)(2003), pp.593-598.

[3] W. Kratschmer, L.D. Lamb, K. Fostiropoulos, D.R. Huffman: Nature Vol. 347 (1990), p.354.

[4] R.D. Shull, L.H. Bennett: Nanostruct. Mater Vol. 1 (1992), pp.83-88.

[5] X.L. Dong, Z.D. Zhang, Y.C. Chuang, S.R. Jin: Phys. Rev. B Vol. 60 (1999), pp.3017-3024.

[6] Z.D. Zhang, J.L. Yu, J.G. Zheng, I. Skorvanek, J. Korvac, X.L. Dong, Z.J. Li, S.R. Jin, H.C. Yang, Z.J. Guo, W. Liu, X.G. Zhao: Phys. Rev. B Vol. 64 (2001) , p.024404024408.

[7] C. Radloff, N.J.J. Halas: Appl Phys Lett Vol. 79(2001), pp.674-676.

[8] G.M. Shi,Y. Dong, Y. Huang：Chinese Journal of materials research, Vol. 22(2008), pp.379-382.

[9] D.N. Hendrickson., J.M. Hollander, W.L. Jolly: Inorg. Chem. Vol. 9 (1970), pp.612-616.

[10] J.F. Moulder, W.F. Stickle, P.E. Sobol, and K.D. Bomben: Handbook of X-ray Photoelectron Spectroscopy, edited by Jill Chastain(Perkin-Elmer Corporation, Physical Electronics Division, Eden Prairie, MN, 1992), p.25, 55, 81, 83, 85.

[11] D.G. Tong, W. Chu, Y.Y. Luo. etc: Molecular Catalysis A: Chemical Vol. 265(2007), pp.195-204.

[12] Z.X. Zhang: Handbook of Physical Constants, Beijing Science Press, 1979, p.84 (in Chinese).

[13] B. Bokhonov, M . Korchagin, Y. Borisova: Journal of Alloys and Compounds Vol. 372 (2004), pp.141-147.

[14] Z.D. Zhang, J.G. Zheng, I. Skorvanek, G.H. Wen, J. Kovac, F.W. Wang, J.L. Yu, Z.J. Li, X.L. Dong, S.R. Jin, W. Liu, X.X. Zhang:J. Phys. Cond. Matter Vol. 13 (2001), p.1921-(1929).

[15] J. Jiao, S. Seraphin, X. Wang, J.C. Withers: J. Appl. Phys Vol. 80 (1996), pp.2097-2104.

[16] X.L. Dong, Z.D. Zhang, X.G. Zhao, Y.C. Chuang, S.R. Jin and W.M. Sun, J. Mater. Res. Vol. 14 (1999), pp.1782-1790.