Substitutional and interstitial doping in LaCo5 system for the development of hard magnetic properties: A first principles study

Journal Article · 04 May 2020 · Journal of Alloys and Compounds

DOI: https://doi.org/10.1016/j.jallcom.2020.155263 · OSTI ID:1618181

Ucar, Huseyin ^[1]; Choudhary, Renu ^[2]; Paudyal, Durga ^[2]

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1. California State Polytechnic Univ., Pomona, CA, (United States)
2. Ames Lab., and Iowa State Univ., Ames, IA (United States)

We investigate here the changes in the electronic structure at the transition metal sites of the RE-TM5 structure (RE = Rare Earth, TM = Transition Metal) while doping the interstitial sites with nitrogen. LaCo₅ compound is taken as the baseline compound owing to its critically needed intrinsic magnetic properties such as magneto-crystalline anisotropy energy (MAE) of ≈5 meV/fu [1] due to the contributions from the cobalt network. In addition, because of the lack of 4f electrons in lanthanum, complications originating from the treatment of the 4f localized electrons are absent in this compound; making it an ideal reference material to all the isostructural RE-TM₅ compounds. Addition of nitrogen is shown to reduce the local spin moments of the nearest TM due to the hybridization present between N-2p states and the TM-3d states. More importantly, we showed here how a planar anisotropy becomes a strong uniaxial anisotropy after the addition of nitrogen into LaCo₂Fe₃ and LaCo₂Mn₃, and linked this transformation to the band structure changes after nitrogenation. Effect of nitrogen in Sm₂Fe₁₇ and NdFe₁₂ is already known, in that, it increases the Curie temperature, and induces a strong magnetic anisotropy for both compounds. In this study we show that similar trends can be observed in RM-TM₅ type compounds providing a challenge for experimentalists to realize these compositions through appropriate synthesis. Future studies will be conducted to understand whether the additions of nitrogen may induce a structural transformation from 1–5 into 2-12 or 2-17 type intermetallics.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: DE-AC02-07CH11358
• OSTI ID: 1618181
• Alternate ID(s): OSTI ID: 1630109
• Report Number(s): IS-J-10-217
• Journal Information: Journal of Alloys and Compounds, Vol. 836, Issue C; ISSN 0925-8388
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English