J. Mater. Sci. Technol. ›› 2021, Vol. 68: 124-131.DOI: 10.1016/j.jmst.2020.06.040

• Research Article • Previous Articles     Next Articles

Magnetic transformation of Mn from anti-ferromagnetism to ferromagnetism in FeCoNiZMnx (Z = Si, Al, Sn, Ge) high entropy alloys

Bin Zhanga, Yuping Duana,*(), Haifeng Zhangb, Shuo Huangc, Guojia Mad, Tongmin Wanga,*(), Xinglong Donge, b   

  1. a Key Laboratory of Solidification Control and Digital Preparation Technology (Liaoning Province), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116085, China
    b Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering, Northeastern University, Shenyang, 110819, China
    c Applied Materials Physics, Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm, SE-100 44, Sweden
    d Beijing Aeronautical Manufacturing Technology Research Institute, Beijing, 100024, China
    e Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Liaoning, 116024, China
  • Received:2020-02-09 Revised:2020-06-08 Accepted:2020-06-09 Published:2021-03-30 Online:2021-05-01
  • Contact: Yuping Duan,Tongmin Wang
  • About author:tmwang@dlut.edu.cn(T. Wang).
    *E-mail addresses: duanyp@dlut.edu.cn (Y. Duan),

Abstract:

We design high entropy alloys (HEAs) with different induction elements (Si/Al/Sn). In order to keep the crystal structure invariant and to investigate how the increment in saturation magnetization (Ms) is caused only by the change of electron spin state, each set of HEAs contains a different amount of Mn. Synergistic effects among induction elements that induce the magnetic transformation of Mn from anti-ferromagnetism to ferromagnetism are found. Ms of added Mn reduces when a particular induction element (Si0.4/Al0.4/Sn0.4) exists, while a larger increment of Ms appears when two induction elements coexist, Si0.4Al0.4 (25.79 emu/g) and Sn0.4Al0.4 (15.43 emu/g). This is reflected in the microcosmic magnetic structure for the emergence of closed domains due to large demagnetization energy, which is confirmed by the Lorentz transmission electron microscope (LTEM) data. The calculated magnetic moments and the exchange integral constants from density functional theory based on the Exact Muffin-Tin Orbits formalism reveal that the magnetic state and the strength of ferromagnetic and anti-ferromagnetic coupling determine the variation of Ms in different chemical environments. The difference in energy levels of coexisting multiple induction elements also leads to a larger increment of Ms, Si0.4Al0.4Sn0.4 (29.78 emu/g), and Si0.4Al0.4Ge0.4Sn0.4 (31.00 emu/g).

Key words: High entropy alloy, Magnetic transformation, Density functional theory, Magnetic moment, Exchange integral constants