›› 2014, Vol. 23 ›› Issue (7): 76105-076105.doi: 10.1088/1674-1056/23/7/076105

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Physical properties of FePt nanocomposite doped with Ag atoms：First-principles study

贾永飞a, 舒小林a, 谢勇b, 陈子瑜a   

  1. a Department of Physics, Beihang University, Beijing 100191, China;
    b National Center for Nanoscience and Technology, Beijing 100190, China
  • 收稿日期:2013-09-04 修回日期:2013-12-13 出版日期:2014-07-15 发布日期:2014-07-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11274033 and 61227902) and the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20131102130005).

Physical properties of FePt nanocomposite doped with Ag atoms：First-principles study

Jia Yong-Fei (贾永飞)a, Shu Xiao-Lin (舒小林)a, Xie Yong (谢勇)b, Chen Zi-Yu (陈子瑜)a   

  1. a Department of Physics, Beihang University, Beijing 100191, China;
    b National Center for Nanoscience and Technology, Beijing 100190, China
  • Received:2013-09-04 Revised:2013-12-13 Online:2014-07-15 Published:2014-07-15
  • Contact: Chen Zi-Yu E-mail:chenzy@buaa.edu.cn
  • About author:61.66.Dk; 71.15.Mb; 64.60.Cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11274033 and 61227902) and the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20131102130005).

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摘要： L10 FePt nanocomposite with high magnetocrystalline anisotropy energy has been extensively investigated in the fields of ultra-high density magnetic recording media. However, the order-disorder transition temperature of the nanocomposite is higher than 600 ℃, which is a disadvantage for the use of the material due to the sustained growth of FePt grain under the temperature. To address the problem, addition of Ag atoms has been proposed, but the magnetic properties of the doped system are still unclear so far. Here in this paper, we use first-principles method to study the lattice parameters, formation energy, electronic structure, atomic magnetic moment and order-disorder transition temperature of L10 FePt with Ag atom doping. The results show that the formation energy of a Ag atom substituting for a Pt site is 1.309 eV, which is lower than that of substituting for an Fe site 1.346 eV. The formation energy of substituting for the two nearest Pt sites is 2.560 eV lower than that of substituting for the further sites 2.621 eV, which indicates that Ag dopants tend to segregate L10 FePt. The special quasirandom structures (SQSs) for the pure FePt and the FePt doped with two Ag atoms at the stable Pt sites show that the order-disorder transition temperatures are 1377 ℃ and 600 ℃, respectively, suggesting that the transition temperature can be reduced with Ag atom, and therefore the FePt grain growth is suppressed. The saturation magnetizations of the pure FePt and the two Ag atoms doped FePt are 1083 emu/cc and 1062 emu/cc, respectively, indicating that the magnetic property of the doped system is almost unchanged.

关键词: FePt, Ag, density functional theory (DFT), order-disorder transition

Abstract: L10 FePt nanocomposite with high magnetocrystalline anisotropy energy has been extensively investigated in the fields of ultra-high density magnetic recording media. However, the order-disorder transition temperature of the nanocomposite is higher than 600 ℃, which is a disadvantage for the use of the material due to the sustained growth of FePt grain under the temperature. To address the problem, addition of Ag atoms has been proposed, but the magnetic properties of the doped system are still unclear so far. Here in this paper, we use first-principles method to study the lattice parameters, formation energy, electronic structure, atomic magnetic moment and order-disorder transition temperature of L10 FePt with Ag atom doping. The results show that the formation energy of a Ag atom substituting for a Pt site is 1.309 eV, which is lower than that of substituting for an Fe site 1.346 eV. The formation energy of substituting for the two nearest Pt sites is 2.560 eV lower than that of substituting for the further sites 2.621 eV, which indicates that Ag dopants tend to segregate L10 FePt. The special quasirandom structures (SQSs) for the pure FePt and the FePt doped with two Ag atoms at the stable Pt sites show that the order-disorder transition temperatures are 1377 ℃ and 600 ℃, respectively, suggesting that the transition temperature can be reduced with Ag atom, and therefore the FePt grain growth is suppressed. The saturation magnetizations of the pure FePt and the two Ag atoms doped FePt are 1083 emu/cc and 1062 emu/cc, respectively, indicating that the magnetic property of the doped system is almost unchanged.

Key words: FePt, Ag, density functional theory (DFT), order-disorder transition

中图分类号:  (Alloys )

  • 61.66.Dk
71.15.Mb (Density functional theory, local density approximation, gradient and other corrections) 64.60.Cn (Order-disorder transformations)