Anisotropy of exchange stiffness based on atomic-scale magnetic properties in the rare-earth permanent magnet 
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Toga, Yuta; Nishino, Masamichi; Miyashita, Seiji; Miyake, Takashi; Sakuma, Atsushi

doi:10.1103/physrevb.98.054418

Cited by 41 publications

(31 citation statements)

References 56 publications

(102 reference statements)

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“…Figure C.6 shows the D a /D c ratio for bcc Fe, fcc Co, and fcc Ni with the tetragonal deformation. The D a /D c ratio in Fe and Ni tend to have a negative correlation with c/a, which is opposite to the cases of SmFe 12 (this work) and Nd 2 Fe 14 B [17]. In contrast, fcc Co has a positive correlation to c/a.…”

Section: Appendix B Spin-wave Stiffness In Bcc Fe Hcp Co Fcc Co Ancontrasting

confidence: 81%

See 1 more Smart Citation

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

Fukazawa

Akai

Harashima

et al. 2018

2018 IEEE International Magnetics Conference (INTERMAG)

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We present spin-wave dispersion in Sm(Fe 1−x Co x ) 12 calculated based on firstprinciples. Anisotropy in the lowest branch of the spin-wave dispersion around the Γ point is discussed. Spin-waves propagate more easily along a * -axis than along c * -axis, especially in SmFe 12 . We also compare values of the spin-wave stiffness with those obtained from an experiment. The calculated values are in good agreement with the experimental values.

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Section: Appendix B Spin-wave Stiffness In Bcc Fe Hcp Co Fcc Co Ancontrasting

confidence: 81%

“…(3). Toga et al [17] has recently reported the values of the exchange stiffness at finite temperatures in their Monte Carlo simulation for Nd 2 Fe 14 B, which is also an Fe-rich rare-earth compound. Though they did not present the value at zero temperature, the order of the exchange stiffness seem to agree with our results for SmFe 12 .…”

Section: Resultsmentioning

confidence: 99%

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

Fukazawa

Akai

Harashima

et al. 2018

2018 IEEE International Magnetics Conference (INTERMAG)

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“…The temperature-dependent A e of Nd 2 Fe 14 B is evaluated through ASM simulation by using VAMPIRE [36] based on the atomistic spin Hamiltonian which is proposed and parameterized previously [37][38][39][40][41]. Detailed formulations for the ASM of Nd 2 Fe 14 B are provided in the Supplemental Material.…”

Section: Methodsmentioning

confidence: 99%

Anisotropic exchange in Nd–Fe–B permanent magnets

Gong

Evans

Gutfleisch

et al. 2019

Materials Research Letters

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The exchange is critical for designing high-performance Nd-Fe-B permanent magnets. Here we demonstrate through multiscale simulations that the exchange in Nd-Fe-B magnets, including bulk exchange stiffness (A e) in Nd 2 Fe 14 B phase and interface exchange coupling strength (J int) between Nd 2 Fe 14 B and grain boundary (GB), is strongly anisotropic. A e is larger along crystallographic a/b axis than along c axis. Even when the GB Fe x Nd 1−x has the same composition, J int for (100) interface is much higher than that for (001) interface. The discovered anisotropic exchange is shown to have profound influence on the coercivity. These findings enable more freedom in designing Nd-Fe-B magnets by tuning exchange. IMPACT STATEMENT Bulk exchange stiffness in Nd 2 Fe 14 B and interface exchange coupling strength between Nd 2 Fe 14 B and grain boundary are found strongly anisotropic, which have profound influence on the coercivity of Nd-Fe-B magnets.

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“…We have not yet established a formal framework to extract the exchange stiffness constant A m from the DFT-DLM calculations. A similar challenge is encountered when performing calculations based on atomistic spin models [45].…”

Section: Deriving Parameters For Micromagnetics Simulationsmentioning

confidence: 97%

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFe
Patrick
¹
,
Matsumoto
²
,
Staunton
³

2019
Journal of Magnetism and Magnetic Materials
12
2
18
1
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We present a computational study of the compound Y(Co 1−x−y Fe x Cu y ) 5 for 0 ≤ x, y ≤ 0.2. This compound was chosen as a prototype for investigating the cell boundary phase believed to play a key role in establishing the high coercivity of commercial Sm-Co 2:17 magnets. Using density-functional theory, we have calculated the magnetization and magnetocrystalline anisotropy at zero temperature for a range of compositions, modeling the doped compounds within the coherent potential approximation. We have also performed finite temperature calculations for YCo 5 , Y(Co 0.838 Cu 0.162 ) 5 and Y(Co 0.838 Fe 0.081 Cu 0.081 ) 5 within the disordered local moment picture. Our calculations find that substituting Co with small amounts of either Fe or Cu boosts the magnetocrystalline anisotropy K, but the change in K depends strongly on the location of the dopants. Furthermore, the calculations do not show a particularly large difference between the magnetic properties of Cu-rich Y(Co 0.838 Cu 0.162 ) 5 and equal Fe-Cu Y(Co 0.838 Fe 0.081 Cu 0.081 ) 5 , despite these two compositions showing different coercivity behavior when found in the cell boundary phase of 2:17 magnets. Our study lays the groundwork for studying the rare earth contribution to the anisotropy of Sm(Co 1−x−y Fe x Cu y ) 5 , and also shows how a small amount of transition metal substitution can boost the anisotropy field of YCo 5 .

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Anisotropy of exchange stiffness based on atomic-scale magnetic properties in the rare-earth permanent magnet Nd2Fe14B

Cited by 41 publications

References 56 publications

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

Anisotropic exchange in Nd–Fe–B permanent magnets

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFe
Patrick
¹
,
Matsumoto
²
,
Staunton
³

2019
Journal of Magnetism and Magnetic Materials
12
2
18
1
View full text Add to dashboard Cite

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Anisotropy of exchange stiffness based on atomic-scale magnetic properties in the rare-earth permanent magnet Nd2Fe14B

Cited by 41 publications

References 56 publications

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)12

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)12

Anisotropic exchange in Nd–Fe–B permanent magnets

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFePatrick1, Matsumoto2, Staunton3 2019Journal of Magnetism and Magnetic Materials122181View full textAdd to dashboardCite

Contact Info

Product

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About

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

First-principles Study of Spin-Wave Dispersion in Sm(FeCo)₁₂

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFe
Patrick
¹
,
Matsumoto
²
,
Staunton
³

2019
Journal of Magnetism and Magnetic Materials
12
2
18
1
View full text Add to dashboard Cite