Phase stability and coercivity in La2Fe14B magnet

Critical rare-earth free La2Fe14B (2:14:1) has the potential to be a gap permanent magnet. However, La2Fe14B decomposes into La, α-Fe, and LaFe4B4 phases below 1067 K. The phase stability and coercivity have been studied in La2Fe14B magnet using first principles DFT (density functional theory) calcu...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:AIP advances 2023-02, Vol.13 (2), p.025211-025211-5
Hauptverfasser: Liu, X. B., Nlebedim, I. C.
Format: Artikel
Sprache:eng
Schlagworte:
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:Critical rare-earth free La2Fe14B (2:14:1) has the potential to be a gap permanent magnet. However, La2Fe14B decomposes into La, α-Fe, and LaFe4B4 phases below 1067 K. The phase stability and coercivity have been studied in La2Fe14B magnet using first principles DFT (density functional theory) calculation and micromagnetic simulation. For a perfect La2Fe14 B cube (edge length of 256 nm) without any structural defects and soft magnetic secondary phases, the coercivity (8.5 kOe) is reduced to ∼40% of its magnetocrystalline anisotropy field (HA = 20 kOe). Further, the coercivity sharply reduces to 3.2 kOe upon forming a thin layer (2 nm) of α-Fe on the surface of the La2Fe14B cube particle. The DFT calculations indicate that a partial replacement of La by other rare-earth (RE) elements can enhance the structural stability of 2:14:1. The gains in cohesive energy are 0.75, 0.10, and 0.33 eV per formula unit in (La0.5RE0.5)2Fe14B with RE = Ce, Pr, and Nd, respectively. Stabilizing the 2:14:1 structure and mitigating the formation of soft magnetic structural defects or impurity phases such as α-Fe is necessary to develop La2Fe14B based magnet, which can be moderately achieved via partial substitution of La by other rare earth elements such as Ce, Pr, and Nd.
ISSN:2158-3226
2158-3226
DOI:10.1063/9.0000403