Stabilization of the tetragonal distortion of Fe<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow /><mml:mi>x</mml:mi></mml:msub></mml:math>Co<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow /><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:math>alloys by C impurities: A potential new permanent magnet

Delczeg‐Czirjak, Erna K.; Edström, Alexander; Werwiński, Mirosław; Rusz, Ján; Skorodumova, Natalia V.; Vitos, Levente; Eriksson, Olle

doi:10.1103/physrevb.89.144403

Cited by 68 publications

(60 citation statements)

References 38 publications

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“…The qualitative shape of the MAE curve as function of Co concentration agrees with experiment for fullpotential calculations in the VCA. However, the quantitative discrepancy is severe as commonly observed when studying the MAE in the VCA [16][17][18]. Calculations in the atomic sphere approximation, treating disorder in the CPA, solve the problem of the quantitative disagreement with experiment on the Fe-rich side of the alloy but instead yield a qualitatively incorrect behavior on the Co-rich side.…”

Section: Discussionmentioning

confidence: 81%

“…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%

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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
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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: Discussionmentioning

confidence: 81%

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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“…As already discussed in the introduction, the tetragonal distortion was predicted by Delczeg-Czirjak et al 13 for Fe-Co alloyed with carbon. The present study proves these findings also for lower C contents of only 2 at%.…”

Section: Magnetic Properties Of the Strained Filmsmentioning

confidence: 68%

“…In a recent study, Delczeg-Czirjak et al 13 calculated that small atoms like carbon may stabilize the strain in Fe-Co. Their DFT calculations identify the preferential positions of the C atoms being interstitials along the c axis of the Fe-Co lattice ( Fig. 1 Our study presents the first results on Fe-Co thin films alloyed with small amounts of carbon.…”

Section: Introductionmentioning

confidence: 99%

Increased magnetocrystalline anisotropy in epitaxial Fe-Co-C thin films with spontaneous strain

Reichel

Giannopoulos

Kauffmann-Weiss

et al. 2014

Journal of Applied Physics

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Rare earth free alloys are in focus of permanent magnet research since the accessibility of the elements needed for nowadays conventional magnets is limited. Tetragonally strained iron-cobalt (Fe-Co) has attracted large interest as promising candidate due to theoretical calculations. In experiments, however, the applied strain quickly relaxes with increasing film thickness and hampers stabilization of a strong magnetocrystalline anisotropy. In our study we show that already 2 at% of carbon substantially reduce the lattice relaxation leading to the formation of a spontaneously strained phase with 3 % tetragonal distortion. In these strained (Fe 0.4 Co 0.6 ) 0.98 C 0.02 films, a magnetocrystalline anisotropy above 0.4 MJ/m 3 is observed while the large polarization of 2.1 T is maintained. Compared to binary Fe-Co this is a remarkable improvement of the intrinsic magnetic properties. In this paper, we relate our experimental work to theoretical studies of strained Fe-Co-C and find a very good agreement.

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“…7 In Fe 30 Co 70 nanowires, a naturally formed hard-magnetic oxide layer with a thickness of 3-4 nm, exchange coupled to a FeCo phase of dimension 40 nm, yields a 20% coercivity increase compared to shape-only anisotropy. 8 It is well-known that carbon doping yields a martensitic distortion of bcc Fe-Co. [9][10][11] Recently, it has been found that Mo doping induced the formation of the tetragonal structure for FeCo alloys, resulting in a magnetocrystalline anisotropy constant of 3.6 Mergs/cm 3 and a coercivity of 1.2 kOe for the Fe 8 CoMo alloy. 12 The challenge is to realize such changes in an alnico-like microstructure.…”

Section: Introductionmentioning

confidence: 99%

Coercivity and nanostructure of melt-spun Ti-Fe-Co-B-based alloys

et al. 2016

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Nanocrystalline Ti-Fe-Co-B-based alloys, prepared by melt spinning and subsequent annealing, have been characterized structurally and magnetically. X-ray diffraction and thermomagnetic measurements show that the ribbons consist of tetragonal Ti3(Fe,Co)5B2, FeCo-rich bcc, and NiAl-rich L21 phases; Ti3(Fe,Co)5B2, is a new substitutional alloy series whose end members Ti3Co5B2 and Ti3Fe5B2 have never been investigated magnetically and may not even exist, respectively. Two compositions are considered, namely Ti11+xFe37.5-0.5xCo37.5−0.5xB14 (x = 0, 4) and alnico-like Ti11Fe26Co26Ni10Al11Cu2B14, the latter also containing an L21-type alloy. The volume fraction of the Ti3(Fe,Co)5B2 phase increases with x, which leads to a coercivity increase from 221 Oe for x = 0 to 452 Oe for x = 4. Since the grains are nearly equiaxed, there is little or no shape anisotropy, and the coercivity is largely due to the magnetocrystalline anisotropy of the tetragonal Ti3(Fe,Co)5B2 phase. The alloy containing Ni, Al, and Cu exhibits a magnetization of 10.6 kG and a remanence ratio of 0.59. Our results indicate that magnetocrystalline anisotropy can be introduced in alnico-like magnets, adding to shape anisotropy that may be induced by field annealing.

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Stabilization of the tetragonal distortion of FexCo1−xalloys by C impurities: A potential new permanent magnet

Cited by 68 publications

References 38 publications

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

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

Increased magnetocrystalline anisotropy in epitaxial Fe-Co-C thin films with spontaneous strain

Coercivity and nanostructure of melt-spun Ti-Fe-Co-B-based alloys

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Stabilization of the tetragonal distortion of FexCo1−xalloys by C impurities: A potential new permanent magnet

Cited by 68 publications

References 38 publications

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

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

Increased magnetocrystalline anisotropy in epitaxial Fe-Co-C thin films with spontaneous strain

Coercivity and nanostructure of melt-spun Ti-Fe-Co-B-based alloys

Contact Info

Product

Resources

About

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

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