First-principles study on electronic structure, magnetic and dielectric properties of Cr-doped Fe₃C

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• 作者：Jian-ping Yang 杨建平 ; Jin Chen 陈津 ; Wei Li 李伟…
• 关键词：Key wordsCr ; doped Fe3C ; electronic structure ; magnetic properties ; dielectric properties
• 刊名：Journal of Central South University
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：23
• 期：9
• 页码：2173-2181
• 全文大小：1,157 KB
• 刊物类别：Engineering
• 刊物主题：Engineering, general
  Metallic Materials
  Chinese Library of Science
  
• 出版者：Central South University, co-published with Springer
• ISSN：2227-5223
• 卷排序：23

文摘

The first-principles calculations were performed to investigate the electronic structure, magnetic and dielectric properties of Cr-doped Fe₃C, in comparison to those of pure Fe₃C and Cr₃C. The obtained results show that the thermodynamic stability of Cr-doped Fe₃C becomes weaker in terms of the larger formation enthalpy, on the contrary, the metallicity and covalency are found to strengthen to some extent. The magnetic moments of Fe₃C, Fe₁₁CrC₄(g), and Fe₁₁CrC₄(s) are respectively 21.36 μ_B/cell, 16.92 μ_B/cell, and 17.62 μ_B/cell, and in Fe₁₁CrC₄(g) and Fe₁₁CrC₄(s), the Fe of Wyckoff positions of 8d and 4c is substituted by Cr. The local magnetic moment of Cr at 8d site is larger than that at 4c site in the doped structure, which is opposite to that of Fe. In low frequency band, the permittivity follows the ranking of Fe₁₁CrC₄(s)>Cr₃C>Fe₁₁CrC₄(g)>Fe₃C. Once exceeding a certain frequency, the sequence will be broken. Besides the electron transition, the polarization of atoms also makes a contribution to the dielectric properties.