Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 MagnetsSm2Fe17X3(

Tribhuwan Pandey

¹

,

Mao‐Hua Du

²

,

David Parker

³

Abstract

Designing a permanent magnet with reduced critical rare earth content is of paramount importance in the development of cost effective modern technologies. Here, by performing comprehensive first-principles calculations we investigate the potential avenues for reducing the critical rare earth content in Sm2Fe17N3 and Sm2Fe17C3 by La/Ce substitution at Sm site. The calculated magnetic properties of base compounds are in good agreement with the previous low temperature (4.2 K) experimental measurements, and show a large axial anisotropy. Although La/Ce substitution results in slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostly remain unchanged. In particular large axial anisotropies of 7.2, and 4.1 MJ/m 3 are obtained for SmCeFe17N3, and SmLaFe17N3, respectively. These values of anisotropies are comparable to the state of the art permanent magnet Nd2Fe14B. The foremost limitation of Sm2Fe17X3 magnets for practical application is the formation nitrogen/carbon vacancies at high temperatures. By calculating the N(C) vacancy formation energy we show that La/Ce substitution enhances the vacancy formation energy. This will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La/Ce-substituted Sm2Fe17C3, and Sm2Fe17N3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare earth content.

Borderline Magnetism: How Adding Mg to Paramagnetic CeCo3 Makes a 450-K Ferromagnet with Large Magnetic Anisotropy

“…As expected Ce atoms prefers to be anti-aligned with respect to Co with an average magnetic moment (including average orbital moment of 0.23 µ B ) of −0.28 µ B per Ce atom. This is similar to numerous other rare-earth magnet results [56,57]. The calculated total magnetic moment of 10.04 µ B per formula unit is in fair agreement with the 50 K experimental value of ∼ 8.0 µ B .…”

Additive Manufacturing of Anisotropic Sm-Fe-N Nylon Bonded Permanent Magnets

“…image4.emf available at https://authorea.com/users/437046/articles/538959-additivemanufacturing-of-anisotropic-sm-fe-n-nylon-bonded-permanent-magnets [26] , as a magnetic material that has not achieved its full potential of energy products rivalling that of Nd 2 Fe 14 B, due to its high-temperature stability difficulties impeding sintering. Recent first principles calculations [27] suggest substitutions such as La or Ce may enhance its high-temperature stability while maintaining relevant magnetic properties (in particular, sufficient magnetic anisotropy). Such effects, if experimentally confirmed, would presumably persist to additively manufactured magnets as considered here, and would offer the promise of an alternative family of permanent magnets with performance, for both sintered and bonded magnets, comparable to that of Nd 2 Fe 14 B.…”

3D printing of anisotropic Sm–Fe–N nylon bonded permanent magnets

“…Ultimately, this doping process decreases the overall energy product of the magnet. Recent first principles calculations 31 suggest substitutions such as La or Ce may enhance its high-temperature stability while maintaining relevant magnetic properties (in particular, sufficient magnetic anisotropy). Such effects, if experimentally confirmed, would presumably persist to additively manufactured magnets as considered here, and would offer the promise of an alternative family of permanent magnets with performance, for both sintered and bonded magnets, comparable to that of Nd 2 Fe 14 B.…”