Thermal stability of MnBi magnetic materials

Cui, Jianying; Choi, Jung-Pyung; Li, G.; Polikarpov, Evgueni; Darsell, Jens T.; Overman, Nicole; Olszta, Matthew J.; Schreiber, D.; Bowden, Mark E.; Droubay, Timothy C.; Kramer, M. J.; Zarkevich, Nikolai A.; Wang, L L.; Johnson, Duane D.; Marinescu, M.; Takeuchi, Ichiro; Huang, Qingjie; Wu, Hui; Reeve, Hayden; Vuong, Nguyen Van; Liu, J P.

doi:10.1088/0953-8984/26/6/064212

Cited by 91 publications

(72 citation statements)

References 14 publications

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“…Recently, however, the availability (and thus price) of the rare-earth elements became rather volatile, calling for development of replacement materials which would use less or none of * Corresponding author: jan.rusz@physics.uu.se the rare-earth elements. Intense research efforts have started worldwide, revisiting previously known materials, such as Fe 2 P [5][6][7], FeNi [8], or Fe 16 N 2 [9], doing computational data mining among the large family of Heusler alloys [10], exploring the effects of strain [11][12][13][14][15][16][17] and doping by interstitial elements [18,19], multilayers such as Fe/W-Re [20] or, as a limiting case of multilayers, the L1 0 family of compounds [21], or promising Mn-based systems [22][23][24][25][26][27], among others.…”

Section: Introductionmentioning

confidence: 99%

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B

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We have explored, computationally and experimentally, the magnetic properties of (Fe 1−x Co x ) 2 B alloys. Calculations provide a good agreement with experiment in terms of the saturation magnetization and the magnetocrystalline anisotropy energy with some difficulty in describing Co 2 B, for which it is found that both full potential effects and electron correlations treated within dynamical mean field theory are of importance for a correct description. The material exhibits a uniaxial magnetic anisotropy for a range of cobalt concentrations between x = 0.1 and x = 0.5. A simple model for the temperature dependence of magnetic anisotropy suggests that the complicated nonmonotonic behavior is mainly due to variations in the band structure as the exchange splitting is reduced by temperature. Using density functional theory based calculations we have explored the effect of substitutionally doping the transition metal sublattice by the whole range of 5d transition metals and found that doping by Re or W elements should significantly enhance the magnetocrystalline anisotropy energy. Experimentally, W doping did not succeed in enhancing the magnetic anisotropy due to formation of other phases. On the other hand, doping by Ir and Re was successful and resulted in magnetic anisotropies that are in agreement with theoretical predictions. In particular, doping by 2.5 at. % of Re on the Fe/Co site shows a magnetocrystalline anisotropy energy which is increased by 50% compared to its parent (Fe 0.7 Co 0.3 ) 2 B compound, making this system interesting, for example, in the context of permanent magnet replacement materials or in other areas where a large magnetic anisotropy is of importance.

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Section: Introductionmentioning

confidence: 99%

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B

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“…The directionally-solidified LTP MnBi shows a remanent magnetic flux density (B r ) of 0.8 T and (BH) max of 17 MGOe at 290 K [7]. However, arc-melted and mechanically-milled LTP MnBi powder shows a low B r of 0.7 T and (BH) max of 11.00 MGOe [8] and B r of 0.7 T and (BH) max of 11.95 MGOe [9] at 300 K. Therefore, it is imperative to predict the theoretical limit of (BH) max for the LTP MnBi magnet.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure and Maximum Energy Product of MnBi

Park

Hong

Lee

et al. 2014

Metals

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Abstract:We have performed first-principles calculations to obtain magnetic moment, magnetocrystalline anisotropy energy (MAE), i.e., the magnetic crystalline anisotropy constant (K), and the Curie temperature (T c ) of low temperature phase (LTP) MnBi and also estimated the maximum energy product (BH) max at elevated temperatures. The full-potential linearized augmented plane wave (FPLAPW) method, based on density functional theory (DFT) within the local spin density approximation (LSDA), was used to calculate the electronic structure of LPM MnBi. The respectively. The (BH) max at the elevated temperatures was estimated by combining experimental coercivity (H ci ) and the temperature dependence of magnetization (M s (T)). The (BH) max is 17.7 MGOe at 300 K, which is in good agreement with the experimental result for directionally-solidified LTP MnBi (17 MGOe). In addition, a study of electron density maps and the lattice constant c/a ratio dependence of the magnetic moment suggested that doping of a third element into interstitial sites of LTP MnBi can increase the M s . OPEN ACCESSMetals 2014, 4 456

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“…The FORC diagrams were obtained at different temperatures ranging from 250 to 535 K. To avoid structural changes due to eutectic reaction [12] in the material, we restrict our measurements up to 535 K, despite the fact that thermal stability of LTP-MnBi up to 650 K has been reported [11]. Hence we resort to temperatures lower than 535 K during FORC analysis except for one sample (HC 1).…”

Section: B Forc Diagramsmentioning

confidence: 99%

“…Synthesis of highly ordered and pure nanocrystalline MnBi requires a well-defined milling and annealing treatment [10][11][12]. Employing the proper synthesis technique is important to obtain high-performance magnets with large coercive fields (H c ).…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependent first-order reversal curve measurements on unusually hard magnetic low-temperature phase of MnBi

et al. 2017

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We have performed first-order reversal curve (FORC) measurements to investigate the irreversible magnetization processes in the low-temperature phase of MnBi. Using temperature-dependent FORC analysis, we are able to provide a clear insight into the effects of microstructural parameters such as grain diameter, shape, and surface composition on the coercivity of nucleation hardened permanent magnet MnBi. FORC diagrams of MnBi show a unique broadening and narrowing of the coercive field distribution with increasing temperature. We were able to microscopically identify the reason for this behavior, based on the shift in the single domain critical diameter from nearly 1 to 2 μm, thereby changing the dependence of coercivity with particle size. This is based on a strong increase in the uniaxial anisotropy constant with increasing temperature. Furthermore, the results also give an additional confirmation that the magnetic hardening in low-temperature phase MnBi occurs due to nucleation mechanisms. In our case, we show that temperature-dependent FORC measurements provide a powerful tool for the microscopic understanding of high-performance permanent magnet systems.

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Thermal stability of MnBi magnetic materials

Cited by 91 publications

References 14 publications

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B

Electronic Structure and Maximum Energy Product of MnBi

Temperature-dependent first-order reversal curve measurements on unusually hard magnetic low-temperature phase of MnBi

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Thermal stability of MnBi magnetic materials

Cited by 91 publications

References 14 publications

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping byEdström1, Werwiński2, Iuşan3 et al. 2015Phys. Rev. B

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping byEdström1, Werwiński2, Iuşan3 et al. 2015Phys. Rev. B

Electronic Structure and Maximum Energy Product of MnBi

Temperature-dependent first-order reversal curve measurements on unusually hard magnetic low-temperature phase of MnBi

Contact Info

Product

Resources

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Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B

Magnetic properties of(Fe1−xCox)2Balloys and the effect of doping by
Edström¹,
Werwiński²,
Iuşan³
et al. 2015
Phys. Rev. B