Anisotropy of mechanical properties in sintered Nd–Fe–B magnets

Wang, H.J.; Guo, Zhaohui; Li, A.H.; Li, X.M.; Li, W.

doi:10.1016/j.jmmm.2006.01.169

Cited by 20 publications

(2 citation statements)

References 12 publications

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“…However, on increasing the Si content above y > 1.8, a change in the nature of the FM phase transition from first-order to second-order takes place that results in a considerable reduction of the useful MCE. A firstprinciples calculation by Wang et al [26] indicated that hybridization between the Fe-d and Si-p states is linked to the reduction of Fe magnetic moment as well as to the smearing of the first-order type transition for alloys with high Si-content.…”

Section: Introductionmentioning

confidence: 99%

Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂

Gercsi

Fuller

Sandeman

et al. 2017

J. Phys. D: Appl. Phys.

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We present a systematic investigation of the effect of H, B, C, and N interstitials on the electronic, lattice and magnetic properties of La(Fe,Si) 13 using density functional theory. The parent LaSiFe 12 alloy has a shallow, double-well free energy function that is the basis of itinerant metamagnetism. On increasing the dopant concentration, the resulting lattice expansion causes an initial increase in magnetisation for all interstitials that is only maintained at higher levels of doping in the case of hydrogen. Strong s-p band hybridisation occurs at high B,C and N concentrations. We thus find that the electronic effects of hydrogen doping are much less pronounced than those of other interstitials, and result in the double-well structure of the free energy function being least sensitive to the amount of hydrogen. This microscopic picture accounts for the vanishing first order nature of the transition by B,C, and N dopants as observed experimentally. We use our calculated electronic density of states for LaSiFe 12 and the hydrogenated alloy to infer changes in magneto-elastic coupling and in phonon entropy on heating through T C by calculating the fermionic entropy arXiv:1407.7975v2 [cond-mat.mtrl-sci] 13 Dec 2017Electronic structure, metamagnetism and thermopower of LaSiFe 12 and interstitially doped LaSiFe 12 2 due to the itinerant electrons. Lastly, we predict the electron thermopower in a spinmixing, high temperature limit and compare our findings to recent literature data.

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Section: Introductionmentioning

confidence: 99%

Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂

Gercsi

Fuller

Sandeman

et al. 2017

J. Phys. D: Appl. Phys.

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“…Hence the production and application of Nd-Fe-B magnets have been increased enormously. [1][2][3] To take full advantage of rich resources, the effort to reduce the amount of neodymium in Nd-Fe-B magnet by substituting partial Nd with cerium has been made in recent years. For economic and environmental pressures arising from the large-scale consumption of neodymium, [4][5][6][7][8][9][10] some work has been done to apply cerium to magnets.…”

Section: Introductionmentioning

confidence: 99%

Effects of spacer layers on magnetic properties and exchange couplings of Nd–Fe–B/Nd–Ce–Fe–B multilayer films

Sun¹,

Zhu²,

Liu³

et al. 2017

Chinese Phys. B

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The influences of the spacer-layer Ta on the structures and magnetic properties of NdFeB/NdCeFeB multilayer films are investigated via DC sputtering under an Ar pressure of 1.2 Pa. An obvious (00l) texture of the hard phase is observed in each of the films, which indicates that the main phase of the film does not significantly change with Ta spacer-layer thickness. As a result, both the remanence and the saturation magnetization of the magnet first increase and then decrease, and the maximum values of 4πM r and H cj are 10.4 kGs (1 Gs = 10 −4 T) and 15.0 kOe (1 Oe = 79.5775 A•m −1 ) for the film with a 2-nm-thick Ta spacer-layer, respectively, where the crystalline structures are columnar shape particles. The measured relationship between irreversible portion D(H) = −∆M irr /2M r and H indicates that the nucleation field of the film decreases with spacer layer thickness increasing, owing to slightly disordered grains near the interface between different magnetic layers.

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Effects of thermal stress induced by cyclic heat treatment on sintered (Nd, Dy)-Fe-B magnets

Kim

Lee

et al. 2010

Met. Mater. Int.

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We investigated the mechanisms of coercive force enhancement on Nd 11 Dy 4 Fe 76.5 TM 2.5 B 6 (TM = Co, Cu, Al) induced by a number of cyclic heat treatments (CHT) at temperatures from 350°C to 450°C. The difference in thermal expansion coefficients between Nd-rich and Nd 2 Fe 14 B phases induced penetration of the Nd-rich phase into the Nd 2 Fe 14 B grain boundary through capillary force and compress pressure by CHT. Also, dislocations in the Nd 2 Fe 14 B grain were formed by thermal stresses from thermal expansion and contraction, which caused the domain wall pinning effect. Consequently, coercivity was enhanced from 2,303 kA/m before CHT to 2,480 kA/m after CHT, and a remanence of 1.18 T was maintained after two cycles.

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Anisotropy of mechanical properties in sintered Nd–Fe–B magnets

Cited by 20 publications

References 12 publications

Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂

Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂

Effects of spacer layers on magnetic properties and exchange couplings of Nd–Fe–B/Nd–Ce–Fe–B multilayer films

Effects of thermal stress induced by cyclic heat treatment on sintered (Nd, Dy)-Fe-B magnets

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Anisotropy of mechanical properties in sintered Nd–Fe–B magnets

Cited by 20 publications

References 12 publications

Electronic structure, metamagnetism and thermopower of LaSiFe12and interstitially doped LaSiFe12

Electronic structure, metamagnetism and thermopower of LaSiFe12and interstitially doped LaSiFe12

Effects of spacer layers on magnetic properties and exchange couplings of Nd–Fe–B/Nd–Ce–Fe–B multilayer films

Effects of thermal stress induced by cyclic heat treatment on sintered (Nd, Dy)-Fe-B magnets

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Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂

Electronic structure, metamagnetism and thermopower of LaSiFe₁₂and interstitially doped LaSiFe₁₂