Engineering perpendicular magnetic anisotropy in Fe via interstitial nitrogenation: N choose <i>K</i>

Zhang, Hongbin; Dirba, Imants; Helbig, Tim; Alff, Lambert; Gutfleisch, Oliver

doi:10.1063/1.4967285

Cited by 17 publications

(13 citation statements)

References 24 publications

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“…The change in crystallographic symmetry can affect the magnetic anisotropy in such regions. For instance, several studies have reported that an increase of tetragonality in Fe, supported by interstitial nitrogen atoms, can increase the magnetic anisotropy energy [50][51][52][53]. Theoretical studies explain that the tetragonality in Fe stabilizes orbital magnetic moments and enhances the magnetic anisotropy via spin-orbit coupling [53,54].…”

Section: Resultsmentioning

confidence: 99%

“…For instance, several studies have reported that an increase of tetragonality in Fe, supported by interstitial nitrogen atoms, can increase the magnetic anisotropy energy [50][51][52][53]. Theoretical studies explain that the tetragonality in Fe stabilizes orbital magnetic moments and enhances the magnetic anisotropy via spin-orbit coupling [53,54]. Although voids and impurity nanoparticles may be regarded as the pinning points with respect to the motion of the magnetic domain walls [55], no shoulder can be observed in the case of residual scattering at 10 T, indicating that HPT-Fe is likely to contain few such nanostructures.…”

Section: Resultsmentioning

confidence: 99%

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Anomalous magnetic anisotropy and magnetic nanostructure in pure Fe induced by high-pressure torsion straining

Oba

Adachi

Todaka

et al. 2020

Phys. Rev. Research

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The formation of nanosized spin misalignment can be observed in pure Fe processed via high-pressure torsion (HPT) straining. The magnetic field dependence of the small-angle neutron-scattering profiles indicates that spin misalignment is conserved in magnetic fields up to 10 T. This result demonstrates that HPT straining provides anomalous magnetic anisotropy in pure Fe due to the high densities of the grain boundaries and lattice defects.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Anomalous magnetic anisotropy and magnetic nanostructure in pure Fe induced by high-pressure torsion straining

Oba

Adachi

Todaka

et al. 2020

Phys. Rev. Research

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“…An interesting question is how such tetragonal distortions can be stabilized. We suspect that light interstitial atoms such as H, B, C, and N will lead to substantial tetragonal distortions, as recently investigated in Fe [61] and FeCo [62,63] alloys. Systematic calculations have been performed on compounds with the Cu 3 Au (as for Mn 3 Pt) and Heusler (as for Mn 2 RhPt and Fe 2 CoGa) structures with light interstitials, and the results will be reported elsewhere.…”

Section: Tetragonally Distortion Of Cubic Phasesmentioning

confidence: 79%

“…Finally, concerning the cubic phases in which a tetragonal distortion can induce a large MAE (see Section 4.2.2), we think that adding light interstitial atoms such as H, B, C, and N in these compounds might be a likely way to achieve it in practice [61,62,63]. Figure 18: Strategy to make use of Novamag database for tuning Fe 3 Sn phase.…”

Section: Possible Strategies To Exploit Promising Theoretical Novel Pmentioning

confidence: 99%

Database of novel magnetic materials for high-performance permanent magnet development

Nieves

Arapan

Maudes

et al. 2019

Computational Materials Science

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This paper describes the open Novamag database that has been developed for the design of novel Rare-Earth free/lean permanent magnets. The database software technologies, its friendly graphical user interface, advanced search tools and available data are explained in detail. Following the philosophy and standards of Materials Genome Initiative, it contains significant results of novel magnetic phases with high magnetocrystalline anisotropy obtained by three computational high-throughput screening approaches based on a crystal structure prediction method using an Adaptive Genetic Algorithm, tetragonally distortion of cubic phases and tuning known phases by doping. Additionally, it also includes theoretical and experimental data about fundamental magnetic material properties such as magnetic moments, magnetocrystalline anisotropy energy, exchange parameters, Curie temperature, domain wall width, exchange stiffness, coercivity and maximum energy product, that can be used in the study and design of new promising high-performance Rare-Earth free/lean permanent magnets. The results therein contained might provide some insights into the ongoing debate about the theoretical performance limits beyond Rare-Earth based magnets. Finally, some general strategies are discussed to design possible experimental routes for exploring most promising theoretical novel materials found in the database. NOVAMAG H c > M r /2 [5]. Extrinsic properties also depend on temperature, in fact they typically decrease as temperature increases, reducing the magnet's performance, especially close to the Curie temperature T C (i.e. ferromagnetic-paramagenetic transition). The macroscopic behavior is tightly linked to the microscopic properties called intrinsic. Main magnetic intrinsic properties are atomic magnetic moment µ at (the magnetic moment per volume gives the maximum theoretical M s ), exchange interactions J ij (which determine the magnetic order and T C )and magnetocrystalline anisotropy K 1 (that can enhance H c and it is indispensable in modern magnets to get H c > M r /2) [6]. PMs should have high atomic mangetic moments per volume (> 0.1µ B /Å 3 ), strong ferromangetic exchange interactions (able to give T C > 600 K) and high easy axis magnetocrystalline anisotropy (K 1 > 1 MJ/m 3 ) in order to exhibit good extrinsic properties suitable for PM applcations. In particular, magnetic materials with hardness parameter κ = K 1 /(µ 0 M 2 s ) > 1 (called "hard" magnets) are very valuable since can be used to make efficient magnets of any shape [6]. At mesoscopic scale, intergranular structure between the grains and crystallographic defects can strongly affect the performance of a magnet [7]. Therefore, the optimization of the material's microstructure is also very important in the design and devel-

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“…In recent years, major effort has been made to search for the RE-free PM materials [6]. The reason is a growing concern for the RE elements' (Nd, Sm, Dy) sustainability, together with growing demand from the industry for cheap and stable high-temperature PMs [2].…”

Section: Introductionmentioning

confidence: 99%

Large Uniaxial Magnetic Anisotropy of Hexagonal Fe-Hf-Sb Alloys

et al. 2020

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We theoretically investigate the electronic and magnetic structure of Fe 2 Hf. The density functional theory calculations are shown to produce the negative, easy-plane, magnetic anisotropy in the hexagonal Fe 2 Hf. Antimony substitution suppresses the planar magnetization direction and favors the uniaxial magnetic anisotropy, in agreement with experimental observations. Our study suggests the possibility of the chemical control of the magnetic anisotropy in Fe 2 Hf by Sb substitution, and illustrates the potential of (Fe,Sb) 2 + x Hf 1 − x Laves phase alloys for the permanent magnet applications.

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Engineering perpendicular magnetic anisotropy in Fe via interstitial nitrogenation: N choose K

Cited by 17 publications

References 24 publications

Anomalous magnetic anisotropy and magnetic nanostructure in pure Fe induced by high-pressure torsion straining

Anomalous magnetic anisotropy and magnetic nanostructure in pure Fe induced by high-pressure torsion straining

Database of novel magnetic materials for high-performance permanent magnet development

Large Uniaxial Magnetic Anisotropy of Hexagonal Fe-Hf-Sb Alloys

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