Size-dependent magnetic parameters of fcc FePt nanoparticles: Applications to magnetic hyperthermia

M. S. Seehra, V. Singh, P. Dutta, S. Neeleshwar, Y. Y. Chen, C. L. Chen, S. W. Chou, C. C. Chen

研究成果: 雜誌貢獻期刊論文同行評審

64 引文 斯高帕斯(Scopus)


For nominal 3 and 9 nm FePt nanoparticles coated with oleylamine/oleic acid and having a face-centred-cubic (fcc) structure, temperature variations (5-300 K) of magnetization M, ac susceptibility χ′ and χ″ for the frequency range fm = 0.1-1000 Hz and electron magnetic resonance (EMR) spectra at 9.28 GHz are reported. X-ray diffraction of the samples shows fcc structure with a lattice constant a = 3.84 and TEM characterization yields log-normal distributions of the particle sizes with average D = 3.15(0.16) nm and D = 8.70(0.12) nm for the 3 nm and 9 nm samples, respectively. M versus T data for the zero-field-cooled and field-cooled modes yield a blocking temperature TB = 15 K (85 K) for the 3 nm (9 nm) samples whereas the hysteresis loops at 5 K yield a coercivity Hc = 0 Oe (1.4 kOe). Analysis of the data of TB at different fm determined from the peaks in χ″ in ac susceptibility and the temperature variation of the EMR spectra are used to determine the following parameters of the Vogel-Fulcher relaxation for the 3 nm (9 nm) samples respectively: the attempt frequency fo = 8 × 1010 Hz (2 × 10 12 Hz); inter-particle interaction temperature To = 3 K (33 K) and anisotropy Ka = 1.96 × 106 ergs cm -3 (4.3 × 105 ergs cm-3). The use of the above parameters for the calculations of the optimum size for magnetic hyperthermia is analysed and discussed.

期刊Journal of Physics D: Applied Physics
出版狀態已發佈 - 2010

ASJC Scopus subject areas

  • 電子、光磁材料
  • 凝聚態物理學
  • 聲學與超音波
  • 表面、塗料和薄膜


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